Catnip immunity and alternatives

Estimation of catnip immunity rates by country with meta-analysis and surveys, and discussion of catnip alternatives.
statistics, psychology, meta-analysis, R, power-analysis, survey, Bayes, genetics, experiments, cats, bibliography
2015-11-072019-06-19 in progress certainty: likely importance: 5

Not all cats re­spond to the cat­nip stim­u­lant; the rate of re­spon­ders is gen­er­ally es­ti­mated at ~70% of cats. A meta-analy­sis of cat­nip re­sponse ex­per­i­ments since the 1940s in­di­cates the true value is ~62%. The low qual­ity of stud­ies and the re­port­ing of their data makes ex­am­i­na­tion of pos­si­ble mod­er­a­tors like age, sex, and coun­try diffi­cult. Cat­nip re­sponses have been recorded for a num­ber of species both in­side and out­side the Fe­l­i­dae fam­i­ly; of them, there is ev­i­dence for a cat­nip re­sponse in the Fe­l­i­dae, and, more un­cer­tain­ly, the Para­dox­uri­nae, and Her­pesti­nae.

To ex­tend the analy­sis, I run large-s­cale on­line sur­veys mea­sur­ing cat­nip re­sponse rates glob­ally in do­mes­tic cats, find­ing high het­ero­gene­ity but con­sid­er­able rates of cat­nip im­mu­nity world­wide.

As a piece of prac­ti­cal ad­vice for cat-hal­lu­cino­gen som­me­liers, I treat cat­nip re­sponse & find­ing cat­nip sub­sti­tutes as a de­ci­sion prob­lem, mod­el­ing it as a Markov de­ci­sion process where one wishes to find a work­ing psy­choac­tive at min­i­mum cost. Bol et al 2017 mea­sured mul­ti­ple psy­choac­tives si­mul­ta­ne­ously in a large sam­ple of cats, per­mit­ting pre­dic­tion of re­sponses con­di­tional on not re­spond­ing to oth­ers. (The so­lu­tion to the spe­cific prob­lem is to test in the se­quence cat­nip → hon­ey­suckle → sil­vervine → Va­ler­ian.)

For dis­cus­sion of cat psy­chol­ogy in gen­er­al, see my re­view.

(Nepeta cataria) is a plant which causes stim­u­lated and ex­citable be­hav­ior in many do­mes­tic cats, which is fun to play with. It is the best known of at least a dozen plants with psy­choac­tive effects on cats, and far more pop­u­lar, cheap­er, and eas­ily pur­chased than al­ter­na­tives like , , or . How­ev­er, a large frac­tion of cats do not re­spond (non-re­sponse may be a ge­netic trait given Neil Bow­man Todd 1962’s pedi­gree chart) but may re­spond to one of the al­ter­na­tives. For ex­am­ple, of my fam­i­ly’s two cats, nei­ther re­sponds to cat­nip but one re­sponds to va­le­ri­an, one to hon­ey­suck­le, and both to sil­vervine.

This raises sev­eral ques­tions:

  1. what frac­tion of cats, ex­act­ly, are cat­nip-im­mune?
  2. how often do the cat­nip al­ter­na­tives work?
  3. does im­mu­nity to one al­ter­na­tive pre­dict im­mu­nity to oth­ers?
  4. since some al­ter­na­tives can be hard to find and ex­pen­sive, what is the op­ti­mal or­der of al­ter­na­tives a cat owner should try to find one that works?

Population frequency of catnip response

Literature review

Cat­nip is fre­quently dis­cussed in the pop­u­lar & sec­ondary lit­er­a­ture with­out ci­ta­tion, and after track­ing down claims, the pri­mary lit­er­a­ture on cat­nip effects & re­sponse is rel­a­tively small1, with most re­search fo­cused on the chem­i­cal syn­the­sis of the ac­tive in­gre­di­ents, botan­i­cal stud­ies, or in­ves­ti­gat­ing the pos­si­ble com­mer­cial ap­pli­ca­tions as in­sec­ti­cide & in­sect re­pel­lent; the best lit­er­a­ture re­view re­mains Tucker & Tucker 1987. Key pa­pers:

  • McEl­vain et al 1942, “The con­stituents of the volatile oil of cat­nip. II. The neu­tral com­po­nents. Nepetalic an­hy­dride”:

    tested ex­tracted nepeta­lac­tone and caryophyl­lene on 10 li­ons of un­spec­i­fied but mixed genders/ages; the 7 adults all re­sponded to the nepeta­lac­tone and not the caryophyl­lene (the 3 cubs re­sponded to noth­ing).

  • Todd 1962,

    14 re­spon­ders, 12 non-re­spon­ders in a Siamese breed­ing colony so 46% im­mu­nity rate in this sam­ple. (8 male re­spon­ders, 6 fe­male re­spon­ders, 2 male non-re­spon­ders, 10 fe­male non-re­spon­der­s.) Todd also sur­veyed cats in lo­cal an­i­mal shelters/hospitals, find­ing 26 of 84 sam­pled were non-re­spon­ders or a ~31% im­mu­ni­ty. Todd con­sid­ers the ge­netic pat­tern most con­sis­tent with a fairly com­mon ge­netic vari­ant (by : ; , then ) which is au­to­so­mal dom­i­nant; this would im­ply that breed­ing cats for cat­nip re­sponse is highly fea­si­ble.

  • Todd 1963, “The cat­nip re­sponse”

    • In sur­vey­ing the 26 breed­ing colony & 84 lo­cal cats, Todd found no large cor­re­la­tions with sex, breed type (Manx/Siamese/tabby/Agouti), white spot­ting, blue di­lu­tion, poly­dacty­ly, long hair, or cas­tra­tion. (32 male re­spon­ders, 11 male non-re­spon­ders, 26 fe­male re­spon­ders, 15 fe­male non-re­spon­der­s.) Ex­cept the usual ob­ser­va­tion that young kit­tens rarely dis­play a cat­nip re­spon­se: of 39 un­der 12 weeks of age, 4 re­spond­ed.

    • Cross-species re­sults:

      1. Viver­rids (pg42/73), un­spec­i­fied gender/age/species:

        Ta­ble 3. Re­sults of test­ing Viver­rids with cat­nip. Fig­ure in paren­the­ses in­di­cates num­ber of in­di­vid­u­als test­ed. + = pos­i­tive, ?+ = pos­si­bly pos­i­tive, ?- = prob­a­bly neg­a­tive, - = neg­a­tive, I = in­de­ter­mi­nate, an­i­mal would not or did not in­ves­ti­gate leaves.
        Sub­-fam­i­lies Gen­era N + ?+ ?- - I
        Viver­ri­nae Genetta 3 0 0 0 2 1
        Viver­ri­nae Viverra 1 0 0 1 0 0
        Viver­ri­nae Civet­tic­tis 2 0 0 0 1 1
        Para­dox­uri­nae Nan­dinia 5 0 0 3 2 0
        Para­dox­uri­nae Paguma 2 0 0 1 0 1
        Para­dox­uri­nae Arc­tic­tis 3 1 1 0 0 1
        Her­pesti­nae Her­pestes 1 0 0 0 1 0
        Her­pesti­nae Ati­lax 3 0 1 1 1 0
        Her­pesti­nae Ich­neu­mia 1 0 0 0 0 1
        Cryp­to­procti­nae Cryp­to­procta 1 0 0 1 0 0
      2. Hye­nas (Hyenidae): 0⁄3 re­spon­ders of 2 males/1 fe­male (pg41/72), un­spec­i­fied age, genus, or species, pre­sum­ably ei­ther spot­ted or striped hye­nas.

      3. Fe­l­i­dae: (pg42/74). Tod­d’s ta­ble and re­sults have been sum­ma­rized as thus by Tucker & Tuck­er:

        Within the sub­fam­ily Pan­theri­nae of the Fe­l­i­dae, Todd (1963) found the typ­i­cal cat­nip re­sponse in 16 li­ons (Pan­thera leo) (14 pos­i­tive re­spon­ders, 2 neg­a­tive re­spon­der­s), 23 tigers (Pan­thera tigris) (8 in­com­plete re­spon­ders, 13 neg­a­tive re­spon­ders, 2 in­con­clu­sive re­spon­der­s), 18 leop­ards (Pan­thera par­dus) (14 pos­i­tive re­spon­ders, 4 neg­a­tive re­spon­der­s), 8 jaguars (Pan­thera on­ca) (7 pos­i­tive re­spon­ders, 1 neg­a­tive re­spon­der), 4 snow leop­ards (Pan­thera un­cia) (4 pos­i­tive re­spon­der­s), and 1 clouded leop­ard (Ne­ofe­lis [Pan­thera] neb­u­losa). Within the sub­fam­ily Acynonychi­nae of the Fe­l­i­dae, he found that 3 chee­tahs (A­ci­nonyx ju­ba­tus) did not re­spond to cat­nip. Within the sub­fam­ily Fe­li­nae of the Fe­l­i­dae, he found the typ­i­cal cat­nip re­sponse in the 2 bob­cats (Fe­lis [L­ynx] ru­fus) (1 pos­i­tive re­spon­der, 1 neg­a­tive re­spon­der), 1 Eu­ro­pean lynx (Fe­lis [L­ynx] lynx), 5 pumas (Fe­lis [Puma] con­col­or) (2 pos­i­tive re­spon­ders, 2 neg­a­tive re­spon­ders, 1 in­con­clu­sive re­spon­der), 1 Asi­atic golden cat (Fe­lis [Pro­fe­lis] tem­minck­i), 5 ocelots (Fe­lis [Leop­ar­dus] pardal­is) (4 pos­i­tive re­spon­ders, 1 neg­a­tive re­spon­der), and 6 mar­gay cats (Fe­lis [Leop­ar­dus] wiedii) (4 pos­i­tive re­spon­ders, 2 neg­a­tive re­spon­der­s); no cat­nip re­sponse was ob­served in 2 ser­vals (Fe­lis [Lep­tail­u­rus] ser­val), 1 swamp cat or jun­gle cat (Fe­lis chaus), 1 Pal­las’ cat (Fe­lis [Oc­to­colobus] man­ul), 1 leop­ard cat (Fe­lis [Pri­on­ail­u­rus] ben­galen­sis), 1 African golden cat (Fe­lis [Pro­fe­lis] au­rata), 2 fish­ing cats (Fe­lis [Pri­on­ail­u­rus] viver­ri­na), 4 jaguarundis (Fe­lis [Herpailurus/Puma] yagouaroundi), and 1 pam­pas cat (Fe­lis [Lyn­chail­u­rus] pa­jeros).

        The sum­mary of Tod­d’s Fe­l­i­dae re­sults is cor­rect but omits that Todd also used a ques­tion­naire to es­ti­mate 4 re­spon­ders & 13 non-re­spon­ders among the ocelots in ad­di­tion to his per­sonal test­ing of the 5 ocelots but Todd notes he “has reser­va­tions about the va­lid­ity of the data gath­ered by this method” (pos­si­bly be­cause the re­sponse fre­quency 4⁄17 is so differ­ent from his per­sonal 4⁄5 re­sponse fre­quen­cy) so that data is prob­a­bly best ex­clud­ed. Todd also men­tions a re­port of a “” (fe­male hy­brid of a male lion & ti­gress) from de Bary of the Utah Hogle Zo­o­log­i­cal Gar­den who is a cat­nip non-re­spon­der. For the meta-analy­sis, I code the ‘ques­tion­able’ positive/negative re­sponses as con­firmed re­spons­es. Sex is usu­ally un­spec­i­fied, but in­di­vid­u­al-level data is pro­vided on the li­ons, tigers, & leop­ards. I ex­cluded the pam­pas cat and ad­di­tional ques­tion­naire data in line with Tod­d’s notes that the data were highly un­re­li­able.

  • Bates & Siegel 1963, “Ter­penoids. Cis-trans- and tran­s-cis- nepeta­lac­tones”

    They chem­i­cally sep­a­rated the two ; the ex­tracted iso­mer I was mostly in­ac­tive when pre­sented to 8 cats with just 1 more in­ter­ested in I than II (though they cau­tion there might still have been con­t­a­m­i­nat­ing II in the I ex­trac­t), but “three were strongly at­tracted” and “two showed slight pref­er­ence” for iso­mer II (_­tran­s-cis-_nepeta­lac­tone), so ar­guably 5 out of 8 were re­spon­ders. (Breed and sexes un­spec­i­fied.)

  • Konecny 1936, “Be­hav­ioral Ecol­ogy of Feral House Cats in the Gala­pa­gos Is­lands, Ecuador”: wild sur­vey of cats; notes suc­cess­ful use of traps baited with tuna fish & cat­nip.

  • Palen & God­dard 1966, “Cat­nip and oe­strous be­hav­ior in the cat”

    Re­ac­tions: 23 re­spon­ders, 20 non-re­spon­ders, so 47% im­mu­nity rate. (37 male, 28 fe­male, mixed breeds: 6 male re­spon­ders, 6 male non-re­spon­ders, 9 cas­trated male re­spon­ders, 5 cas­trated male non-re­spon­ders, 5 fe­male re­spon­ders, 5 fe­male non-re­spon­ders, 3 spayed fe­male re­spon­ders, 4 spayed fe­male non-re­spon­der­s.)

  • Hayashi 1968a, “Pseudo-Affec­tive Re­flexes of Cats pro­duced by Ex­tracts from the Plant Ac­tini­dia polygama claims to have found no re­sponses in an un­spec­i­fied but prob­a­bly >4 num­ber of cats (as he used “young and old cats of both sexes”) when test­ing nepeta­lac­tone (cat­nip) and ac­tini­dine so­lu­tions, aside from two ac­tini­dine re­ac­tions

  • Hayashi 1968b, “Mo­tor re­flexes of cats to Ac­tini­dia polygama (Japan) and to cat­nip (USA)”

    A 1966 con­fer­ence talk pub­lished in the 1968 pro­ceed­ings, Hayashi 1968 is light on de­tails. Tucker & Tucker sum­ma­rize it as “Hayashi (1968), who tested a wide range of an­i­mals (dogs, rab­bits, mice, rats, guinea pigs, fowls, and cats) with pow­ders of Ac­tini­dia polygama and N. cataria, found that the cat­nip re­sponse is in­duced in cats alone.”, which tells one about as much as the orig­i­nal re­port does:

    …ac­tini­dine (1) and cat­nip…have al­ways been the source of much in­ter­est…When pow­der of these plants was pre­sented to cats, they dis­played a pe­cu­liar be­hav­ior…The re­flex be­hav­ior is in­duced by the smell, not by taste and not via the cir­cu­la­tion. The cat must be tamed by the ex­per­i­menters and must be adult: male or fe­male are quite the same…Once I tried with Eng­lish cats in Lon­don, and with Amer­i­can cats in New York, each time tak­ing ad­van­tage of vis­it­ing my friend’s lab­o­ra­to­ries, but Eng­lish as well as Amer­i­can cats were rather cold…We tried ex­per­i­ments with dogs, rab­bits, mice, rats, guinea pigs and also with fowls but they had no such re­flexes to the plant pow­der…From these re­sults, we pre­sume that the re­flex abil­ity is re­stricted to cats and fe­line species in ver­te­brates, and its re­flex cen­tre would be sit­u­ated in the sub­cor­ti­cal, pre­sum­ably lim­bic, struc­tures…That the phe­nom­e­non is re­stricted to the cat fam­ily is said also in Japan.

    • Q [J.W. John­son Jr]: This is a sim­ple ques­tion that might be rel­e­vant to your point, Doc­tor. In North­ern Vir­ginia, where I live, there are stands or clumps of cat­nip. I’m not aware of house cats vis­it­ing the cat­nip stands while in the liv­ing state. Do you know whether this has been re­port­ed.
    • A [T. Hayashi]: No, I don’t think so. We have nat­ural growths of bushes of ac­ti­dinia polygama in sev­eral parts of Japan, but no­body no­ticed that these bushes at­tracted cats from the vil­lages….In the cen­tral part of Japan we have many ac­ti­dinia dis­trib­uted from north to south. But I have not heard that cats gather in the stands of the plant. Maybe the dry­ing of the plants or burn­ing of them is the most effec­tive.

    From this I gather that Hayashi must have tested at least 2 cats in the USA, 2 in the UK, and 2 in Japan (be­cause he al­ways uses the plural “cats”, and he com­pares the US/UK cats to Japan­ese cat­s). Hayashi 1968a im­plies >=4 cats were used but not their na­tional dis­tri­b­u­tion. To be con­ser­v­a­tive in lieu of more pre­cise data, one would have to code the Hayashi data as 2 cats per coun­try. He does men­tion that the USA/UK cats were “rather cold”, which im­plies an in­ter­me­di­ate but ex­is­tent re­sponse much less than the Japan­ese cats. (It is also in­trigu­ing given Saku­rai et al 1988’s later pos­si­ble im­pli­ca­tion that 16 of 16 cats in Japan re­acted to cat­nip but not for­eign breed­s.) If we as­sume the n of each group of cats is 2, then the re­sponse rate must be 1/1/2 re­spec­tive­ly, as oth­er­wise Hayashi would ei­ther have de­scribed it as no re­sponse like the other species or as the same re­sponse as the Japan­ese cats. The other species are also plu­ral­ized, so at least 2 of each, and all re­sponses must have all been 0 re­spon­ders since “they had no such re­flexes” and it is “re­stricted to cats and fe­line species”. Spe­cific species (pre­sum­ably the other an­i­mals are ei­ther do­mes­tic or lab species), sex­es, breeds, and ages are not giv­en.

  • Waller et al 1969, “Fe­line At­trac­tant, cis,­tran­s-Nepeta­lac­tone: Me­tab­o­lism in the Do­mes­tic Cat”

    In a meta­bolic study, pu­ri­fied nepeta­lac­tone was force-fed to 6 cats in gel cap­sules; as ex­pected due to the ol­fac­tory re­quire­ment (pre­vi­ously demon­strated by Todd with sur­gi­cal ma­nip­u­la­tions of ol­fac­tion), none of the cats ex­hib­ited the cat­nip re­sponse and the re­sult is ir­rel­e­vant.

  • Hatch 1972, “Effect of drugs on cat­nip (Nepeta cataria) in­duced plea­sure be­hav­ior in cats”

    Tested 17 cats ini­tial­ly; 14 re­spon­ders. (Mixed breed, both gen­ders; break­downs of re­sponse not giv­en.) Hatch’s main effort was to­wards us­ing drug ad­min­is­tra­tions to block the cat­nip effects and un­der­mine the sex­ual hor­mone hy­poth­e­sis.

  • Todd as quoted in R.F. Ewer 1973, The Car­ni­vores (pg244):

    Differ­en­tial as­pects of the same scent on differ­ent species are il­lus­trated in some un­pub­lished work by Dr N.B. Todd, which he has kindly al­lowed me to quote. He tested the re­sponses of var­i­ous species to cat­nip and found that a num­ber of viver­rids, al­though clearly able to smell the cat­nip, showed lit­tle in­ter­est: for them it car­ried no mes­sage and had no par­tic­u­lar sig­nifi­cance. I have found the same to be true of and [African dwarf mon­goose]. In the Fe­l­i­dae, the cat-type sex­ual re­sponse was wide­spread but not uni­ver­sal. Amongst the large cats, li­on, leop­ard, jaguar and snow leop­ard re­sponded sex­u­ally but adult tigers did not. The be­hav­ior of im­ma­ture tigers was in­ter­est­ing: they were not sex­u­ally ex­cited but in­stead showed vi­o­lent alarm and re­treated prompt­ly. In view of the propen­sity of the larger species of fe­lids to kill each oth­er’s young and of the fact that un­til quite re­cently the ranges of tiger and lion over­lapped very con­sid­er­ably, both the ab­sence of sex­ual re­sponse in the adult tiger and the fear gen­er­ated in the young may be adap­tive: the for­mer may re­flect a sex­ual iso­lat­ing mech­a­nism; the lat­ter may be pro­tec­tive. Apart from il­lus­trat­ing differ­en­tial re­sponses to the same odour, these ob­ser­va­tions also demon­strate the psy­cho­log­i­cal effects of odours. A piece of ma­te­r­ial im­preg­nated with cat­nip is nei­ther a mate nor an en­emy but it can evoke sex­ual re­sponses or flight: to do so it must act on the cen­tral ner­vous sys­tem so as to change the an­i­mal’s mood - in short, it “makes him sexy” or it “makes him afraid”.

    Tod­d’s re­sults here re­fer to his PhD the­sis, but I have not found any Ewer pub­li­ca­tion on cat­nip thus far.

  • Har­ney et al 1974, “Be­hav­ioral ac­tiv­ity of cat­nip and its con­stituents: nepetalic acid and nepeta­lac­tone”/Harney et al 1978, “Be­hav­ioral and tox­i­co­log­i­cal stud­ies of cy­clopen­tanoid monoter­penes from Nepeta cataria

    Con­sid­ers only in­jec­tions of cat­nip oil into mice/rats.

  • Hill et al 1976, “Species-char­ac­ter­is­tic Re­sponses to Cat­nip by Un­do­mes­ti­cated Fe­lids”; Tucker & Tucker sum­mary (ap­par­ently based on count­ing the de­scrip­tions in Ta­ble 3 or Ta­ble 4):

    Hill et al. (1976) found that li­ons (5 pos­i­tive re­spon­ders, 6 par­tial re­spon­ders, 1 neg­a­tive re­spon­der) and jaguars (3 pos­i­tive re­spon­ders) are ex­tremely sen­si­tive to cat­nip, while tigers (5 neg­a­tive re­spon­der­s), pumas (4 neg­a­tive re­spon­der­s), leop­ards (4 par­tial re­spon­ders, 4 neg­a­tive re­spon­der­s), and bob­cats (2 neg­a­tive re­spon­ders) gave lit­tle or no re­sponse. They also found that both males and fe­males of the same species test alike, while re­pro­duc­tive-age adults are more sen­si­tive than ei­ther aged or im­ma­ture an­i­mals.

  • Hart 1977, “Ol­fac­tion and fe­line be­hav­ior”: short pop­u­lar sum­mary of some as­pects of cat ol­fac­tory ca­pa­bil­i­ties; briefly men­tions cat­nip.

  • Rau­zon 1985, “Feral Cats on Jarvis Is­land: Their Effects and Erad­i­ca­tion”:

    Ac­count of a Pa­cific Is­land; men­tions use of cat­nip in traps, with­out suc­cess, and notes that van Aarde told Rau­zon of “pre­vi­ous low suc­cess rates” us­ing cat­nip as well; pre­sum­ably van Aarde was re­fer­ring to efforts on the South African Mar­ion Is­land (of the ), since while the two cited van Aarde pa­pers do not men­tion cat­nip, a 2002 fol­lowup on suc­cess cites one of the au­thors’ mas­ter the­ses as re­port­ing fail­ure in use of cat­nip oil (suc­cess ul­ti­mately com­ing from dis­ease fol­lowed by in­ten­sive hunting/trapping/poisoning):

  • Saku­rai et al 1988, “Both (4a_S_, 7_S_, 7a_R_) -(+)-Nepeta­lac­tone and Its An­tipode Are Pow­er­ful At­trac­tants for Cats”

    An­other in­ves­ti­ga­tion of which isomers/enantiomers of nepeta­lac­tone are ac­tive, the iso­lated ver­sions were tested in 9 cats with vials of the liq­uid; 7 re­sponded (while the two 6-month olds did­n’t and Saku­rai et al 1988 at­trib­utes the non-re­sponse to their be­ing ‘im­ma­ture’, 6 months sounds old enough for re­ac­tions to have de­vel­ope­d). The cat breeds are spec­i­fied as 4 Japan­ese, 3 Abyssini­an, and 2 Amer­i­can short­-hairs, but not sexes (although Saku­rai used a mix, given their com­ments that “the fe­males showed more emo­tional be­hav­ior than the males…the fe­males were quite re­ac­tive, while the males were not…both of them [i­so­mers] were ex­tremely at­trac­tive to ma­ture cats, es­pe­cially to fe­males”). Pos­si­bly con­tra­dict­ing Bates & Siegel 1963’s re­sults where only 1 iso­mer worked, Saku­rai finds both iso­mers work equally well.

    Con­fus­ing­ly, Saku­rai also men­tions a sec­ond ex­per­i­ment in im­preg­nat­ing fil­ter pa­per with the iso­mers, not­ing that “six­teen Japan­ese cats re­acted to the 0.01mg dose”; it’s un­clear where these cats came from when only 9 cats (4 Japan­ese) were men­tioned for the first ex­per­i­ment, and whether they were se­lected out of a larger group of cats or if it’s im­plied that it was 16 out of 16 re­spon­ders - inas­much as with cat­nip re­sponse rates ~70%, it would be highly im­prob­a­ble for all of a group of 16 cats to be cat­nip re­spon­ders (0.716=0.3%). One pos­si­ble ex­pla­na­tion is that Japan­ese cats, be­ing a his­tor­i­cally iso­lated pop­u­la­tion (eg the ) after their in­tro­duc­tion ~500AD from Ko­rea, may have much higher pop­u­la­tion fre­quen­cies or even fixed the cat­nip mu­ta­tion due to or a 2; on the other hand, if Japan­ese cats were al­most all cat­nip re­spon­ders, you would think some­one would have no­ticed by now. My GS sur­vey finds a ~28% im­mu­nity rate, which is not un­usual at all, sug­gest­ing that Hayashi/Sakurai is some sort of sam­pling er­ror or re­port­ing effect.

  • DeLuca & Kranda 1992, “En­vi­ron­men­tal en­rich­ment in a large an­i­mal fa­cil­ity”:

    TABLE 1. Num­ber of an­i­mals, species-wide, that showed in­ter­est in var­i­ous toys. Key: 0 = none, 1 = 25%, 2 = 50%, 3 = the ma­jor­ity of the an­i­mals. We de­fine in­ter­est as the amount of toy de­struc­tion and/or move­ment that we noted in daily ob­ser­va­tions.

    • …balls: cat­nip: 3
    • balls: punch: 3
    • Cat-a-Comb: NA
    • Purrsuit: 3

    …8-12 cat­s…The cats’ fa­vorite toys - like the 12 in. gi­ant sheep­skin mice (Pe­tra­port, Ana­heim, CA) - con­tained cat­nip. We hung fresh cat­nip in stock­inette bags which the cats quickly pulled down and ul­ti­mately bat­ted into the wa­ter bowls. We gave them cat­nip-treated punch­ball toys (Pe­tra­port, Ana­heim, CA- Fig. 7)-2 in. puffs mounted by a spring to a 6 in. x 6 in. base. The cats al­ways played with these toys, and they lasted longer than the cat­nip bags. The cats also had “Mr. Spats’ Cat-a-combs” groomer (Tarel Seven De­signs, Se­cau­cus, NJ) mounted on the walls. They usu­ally knocked these off [of] the wall and used them as play-things (they man­aged to open the com­part­ment and dig out the cat­nip) rather than as groom­ing tools. Most of the cats spent time play­ing “Purrsuit” (Tarel Seven De­signs, Se­cau­cus, NJ)-ev­ery morn­ing, we placed toys in­side a maze and the cats chased them and tried, with a great deal of suc­cess, to get the smaller ones out. The cats had a pref­er­ence for balls or bells with cat­nip in them, and for golf balls. They ig­nored the Squish balls (Eth­i­cal In­c., Newark, NJ).

    So based on the re­ported data, we can guess that at least 5-7 cats re­sponded to cat­nip of the 8-12 sam­ple, for a best guess of 6 re­spon­ders out of 10 cats. (Mixed breeds, un­spec­i­fied sex.)

  • Ea­son et al 1992, “Toxic Bait and Bait­ing Strate­gies for Feral Cats”/Clapperton et al 1992, “Ex­per­i­men­tal Erad­i­ca­tion of Feral Cats (Fe­lis Catus) from Matakohe (Lime­stone) Is­land, Whangarei Har­bour”: New Zealand, a mix of wild sur­vey and ex­per­i­ment, em­ploy­ing a va­ri­ety of baits & scents in­clud­ing cat­nip. Cat­nip per­formed well among the NZ feral cats: for ex­am­ple, 6 cats ob­served at dusk spent a mean ~200s in­ves­ti­gat­ing a cat­nip odor as op­posed to <50s or ~0s for 3 urine scents (Fig­ure 1), and counts of vis­its to cat­nip odor sta­tions were far higher than for urine, fish oil, or wa­ter con­trols (Table 1: 25 vs 13/12/11). Catnip/catmint only per­formed poorly when used as a food fla­vor­ing in a com­mer­cial cat food (Fig­ure 3), but then per­form­ing well alone & com­bined with in bait (Fig­ure 5/6). They then de­ployed their cat­nip & other baits to poi­son ~5 cats on Matakohe Is­land; the cat­nip bait did not lead to no­tice­ably more bait con­sump­tion, but from the de­scrip­tion, cat­nip re­sponse might not have been no­tice­able or just sam­pling er­ror.

  • Clap­per­ton et al 1994, “De­vel­op­ment and Test­ing of At­trac­tants for Feral Cats, Fe­lis catus L.

    Wild sur­vey and ex­per­i­ment in New Zealand. Cat­nip & sil­vervine were tested as cat lures for trap­ping; si­mul­ta­ne­ous test­ing over mul­ti­ple en­vi­ron­ments showed that cat­nip, sil­vervine, and urine all gar­nered sub­stan­tial at­ten­tion from cats. Clap­per­ton notes that 4⁄4 do­mes­tics and 8⁄20 feral cats re­sponded (pg7). (Sex not spec­i­fied, but breeds were clearly mixed as feral cats are never sin­gle breed­s.)

  • Har­ri­son 1997, “Chem­i­cal at­trac­tants for Cen­tral Amer­i­can fe­lids”: ex­per­i­men­tal test­ing of jaguars, jaguarundi, lit­tle spot­ted cats, mar­gays, ocelots, & pumas of cat­nip and other lures; Har­ri­son re­ports the data in terms of time spent in­ves­ti­gat­ing and “be­hav­ior scores” (the num­ber of ob­served be­hav­iors such as sniffing/vocalizing/rubbing/rolling), and not in terms of in­di­vid­ual re­spon­ders. The re­ported data sug­gests some level of re­sponse in jaguars/jaguarundi/ocelots.

  • Ed­wards et al 1997, “Field eval­u­a­tion of ol­fac­tory lures for feral cats (Fe­lis catus L.) in cen­tral Aus­tralia”: wild sur­vey in Aus­tralia; 15 kinds of lures were test­ed, pit­ting a cat­nip lure (#12) against var­i­ous seafood, blood­-bone mix, male/female cat urine/anal gland se­cre­tions; the 3 best ol­fac­tory lures were sun-dried prawns (#8) & male (#13)/female (#14) urine-se­cre­tions, but not cat­nip - cat­nip re­ceived 2 cat vis­its while the best 3 re­ceived 17/14/7 re­spec­tive­ly. Ed­wards notes their sur­prise at the in­effi­cacy of the cat­nip com­pared to the urine-se­cre­tions, as Clap­per­ton et al 1994 had found cat­nip much su­pe­rior in their NZ ex­per­i­ment and ask, “do cats from differ­ent ar­eas re­spond differ­ently to differ­ent ol­fac­tory stim­uli?”

  • Mc­Daniel et al 2000, “Effi­cacy of lures and hair snares to de­tect lynx”

    Used cat­nip and other com­mer­cial prod­ucts in scent sta­tions to look for ac­tiv­ity of wild lynx. Todd 1963 had al­ready found re­sponses in lynx/puma/bobcats, so un­sur­pris­ingly Mc­Daniel does too, but with wild lynx, it is im­pos­si­ble to know how many to­tal lynx were ex­posed and how many re­act­ed.

  • Mol­sher 2001, “Trap­ping and de­mo­graph­ics of feral cats (Fe­lis catus) in cen­tral New South Wales”: Aus­tralian live trap­ping study us­ing var­ied baits; a bait com­bi­na­tion of catnip/tuna oil/“syn­thetic fer­mented eggs” (SFE); while a small sam­ple, the suc­cess in terms of cats trapped per 100 trap-nights var­ied from 0.5 (fish) to 3.8 (“PUSSON” baits + alu­minum toys on string), with the cat­nip mix at 1.1, sug­gest­ing lit­tle or no ad­van­tage over other baits like rab­bit.

  • Short et al 2002, “Con­trol of feral cats for na­ture con­ser­va­tion. III. Trap­ping”: Aus­tralian trap­ping study, vary­ing bait and tim­ing. Fresh cat­nip bait ranked roughly me­di­an, be­low rabbit/mice/2 com­mer­cial mix­es; cat­nip worked well in the first trap­ping and then poorly after­wards, the au­thors spec­u­lat­ing that the de­cline is “per­haps due to re­mov­ing the pool of sus­cep­ti­ble in­di­vid­u­als.” (To­tal catch­ing: 8 cats out of 118; in a head to head test of 2 traps, one cat­nip and a com­mer­cial mix, the cat­nip trap caught 8 vs 7.)

  • Wells & Egli 2004, “The in­flu­ence of ol­fac­tory en­rich­ment on the be­hav­iour of cap­tive black­-footed cats, Fe­lis ni­gripes:

    6 (Fe­lis ni­gripes), cat­nip did in­ter­est them and cause in­creases in ac­tiv­i­ty, but pa­per does­n’t break down by cat. Not use­ful un­less want to con­tact au­thors for in­di­vid­u­al-level da­ta.

  • Weaver et al 2005, “Use of scented hair snares to de­tect ocelots”: tested 32 ocelots avail­able in 9 fa­cil­i­ties, as well as a wild sur­vey; 27 of the 32 re­sponded to their bait, which was a com­bi­na­tion of a mix “Weaver’s Cat Call” and dried cat­nip; Weaver re­ports that the com­bi­na­tion was ear­lier es­tab­lished in bob­cats & lynx to be much more effec­tive than cat­nip alone, so 84% rep­re­sents an over­es­ti­mate of cat­nip’s effect on ocelots.

  • El­lis 2007, “Sen­sory en­rich­ment for cats (Fe­lis sil­vestris catus) housed in an an­i­mal res­cue shel­ter”; ap­par­ently re­pub­lished as El­lis & Wells 2010, “The in­flu­ence of ol­fac­tory stim­u­la­tion on the be­hav­iour of cats housed in a res­cue shel­ter”

    Shel­ter an­i­mals were given cat­nip-in­fused clothes to play with; El­lis notes that the cat­nip toys were played with more than other scents on av­er­age in the cat­nip group, but made no effort to as­cer­tain how many were cat­nip re­spon­ders.

  • Mas­soco et al 1995, “Be­hav­ioral effects of acute and long-term ad­min­is­tra­tion of cat­nip (Nepeta cataria) in mice”; Bernardi et al 2010, “An­ti­de­pres­san­t-like effects of an ap­o­lar ex­tract and chow en­riched with Nepeta cataria (cat­nip) in mice”

    There is ap­par­ently a vein of stud­ies try­ing cat­nip in hu­mans for an­ti­de­pres­sant effects (rather than the more tra­di­tional painkiller and psy­che­delic effect­s), lead­ing to this ex­per­i­ment in chronic feed­ing cat­nip to mice (ironic as that might sound), find­ing one an­ti­de­pres­san­t-like effect. These can’t be con­sid­ered a cat­nip re­spon­se, though.

  • Schmidt & Kowal­czyk 2006, “Us­ing Scen­t-Mark­ing Sta­tions to Col­lect Hair Sam­ples to Mon­i­tor Eurasian Lynx Pop­u­la­tions” / Davoli et al 2013, “Hair snar­ing and mol­e­c­u­lar ge­netic iden­ti­fi­ca­tion for re­con­struct­ing the spa­tial struc­ture of Eurasian lynx pop­u­la­tions”: wild sur­vey us­ing cat­nip oil and beaver oil; 29 unique in­di­vid­u­als geno­typed

  • Downey et al 2007, “Hair Snares for Non­in­va­sive Sam­pling of Fe­lids in North Amer­i­ca: Do Gray Foxes Affect Suc­cess?”: wild sam­pling in Mex­i­co; cat­nip oil did not at­tract any of the tar­get wild cats, but did at­tract many gray foxes & 14 do­mes­tic cats.

  • Long et al 2007, “Com­par­ing Scat De­tec­tion Dogs, Cam­eras, and Hair Snares for Sur­vey­ing Car­ni­vores”: wild sur­vey, used dried cat­nip; no de­tec­tion of bob­cats

  • Cas­tro-Arel­lano et al 2008, “Hair-Trap Effi­cacy for De­tect­ing Mam­malian Car­ni­vores in the Trop­ics”: wild sur­vey in Mex­i­co, com­par­ing per­fume & cat­nip oil, find­ing cat­nip oil in­fe­rior

  • Re­sende et al 2011, “In­flu­ence of Cin­na­mon and Cat­nip on the Stereo­typ­i­cal Pac­ing of On­cilla Cats (Leop­ar­dus tigri­nus) in Cap­tiv­ity”

    The 8 on­cilla cats’ ac­tiv­ity were mea­sured over sev­eral days after each dose was in­tro­duced into their en­clo­sures. While the doses were small (1g), the cin­na­mon pro­duced sta­tis­ti­cal­ly-sig­nifi­cant over­all av­er­age differ­ence while cat­nip did not, sug­gest­ing none of the on­cilla cats re­sponded to the cat­nip. Nev­er­the­less, like Wells & Egli 2004, can­not be meta-an­a­lyzed.

  • Comer et al 2011, “Bob­cats Do Not Ex­hibit Rub Re­sponse De­spite Pres­ence at Hair Col­lec­tion Sta­tions”: wild sur­vey us­ing cat­nip oil; no near-zero rub­bing

  • Matthew 2012, “A Com­par­i­son of Non­in­va­sive Sur­vey Meth­ods for Mon­i­tor­ing Meso­car­ni­vore Pop­u­la­tions in Ken­tucky”: wild sur­vey; did not break down de­tec­tion rates by lure type

  • Hanke & Dick­man 2013, “Sniffing out the stakes: hair-snares for wild cats in arid en­vi­ron­ments”: Aus­tralian wild sur­vey; cat­nip & va­ler­ian proved in­effec­tive in at­tract­ing cats to the stakes, and they sug­gest that (ap­par­ently de­scended from do­mes­ti­cated cats) may sim­ply be cat­nip im­mune, not­ing their re­sults par­al­lel Mol­sher 2001 & Short et al 2002. (This may be con­nected to Aus­trali­a’s im­port reg­u­la­tions which de­ter bring­ing new cats into the coun­try: a num­ber of hy­brid breeds are banned as well as ori­gin coun­tries; and le­gal cats must be: per­mit­ted, mi­crochipped, ra­bies-vac­ci­nated at least 180 days in ad­vance & tested to con­firm im­mu­ni­ty, not be too preg­nant, treated for in­ter­nal par­a­sites, treated for ex­ter­nal par­a­sites, clin­i­cally ex­am­ined by a Aus­tralian-gov­ern­men­t-ap­proved vet­eri­nar­i­an, and quar­an­tined for at least 10 days.)

  • Portella et al 2013, “As­sess­ing the effi­cacy of hair snares as a method for non­in­va­sive sam­pling of Neotrop­i­cal fe­lids” (Ta­ble 1): wild sur­vey and ex­per­i­ment of cinnamon/vanilla/catnip scent lures on 5 jaguars (Pan­thera onca)/10 ocelots (Leop­ar­dus pardalis)/6 on­cilla cats (Leop­ar­dus tigri­nus)/7 mar­gay cats (Leop­ar­dus wiedii)/6 pumas (Puma con­color)/5 jaguarundis (Puma yagouaroundi). The wild sur­vey yielded no re­sults, while the cap­tive ex­per­i­ment in­di­cated that the puma did not in­ter­act with any lures and at least some of the ocelot/margay/oncilla did, with the strongest effect be­ing vanil­la.

    As Portella et al 2013 mea­sures be­hav­ior in length of time in­ter­act­ing with the scent lures and re­ports only species-level differ­ences, it is im­pos­si­ble to say what frac­tion of the cats were re­spon­ders, other than the to­tal lack of re­sponse of the 6 pumas to any scents show­ing that 0⁄6 of them re­spond­ed.

  • Scaffidi et al 2016, “Iden­ti­fi­ca­tion of the Cat At­trac­tants Isodi­hy­dronepeta­lac­tone and Isoiridomyrmecin from Aca­lypha in­dica”, re­port­ing on Aca­lypha in­di­ca, men­tions in pass­ing (with­out num­bers, and ap­par­ently not re­ported else­where) that

    Christ­mas Is­land is a small is­land off the north-west coast of Aus­tralia that is well known for its unique flora and fau­na…One par­tic­u­lar project has been at­tempt­ing to re­duce the large num­ber of feral cats on the is­land [4] and dur­ing this pro­ject, the re­search team be­came aware of a plant that sev­eral lo­cal res­i­dents sug­gested had a pe­cu­liar effect on cats when the roots of the plant were ex­posed…There are plants such as cat­nip (Nepeta cataria) which have sim­i­lar effects on cats due to the pres­ence of nepeta­lac­tone. [9] How­ev­er, in­ves­ti­ga­tion of cat­nip by the Christ­mas Is­land re­search team found that this plant had no effect on the Christ­mas Is­land cats.

    Founder effect?

  • Pod­dar-Sarkar & Brah­machary 2014, “Chap­ter 15: Pheromones of Tiger and Other Big Cats” note an un­re­ported at­tempt at mea­sur­ing cat­nip re­sponse rates in wild African li­ons:

    Cer­tain per­sons brought cat­nip from Eng­land to George Adamson’s lion camp in Ko­ra, Kenya, and tried to study the effect of this plant on the African lion but no con­clu­sive re­sults were ob­tained (Adam­son 1988, per­sonal com­mu­ni­ca­tion).

  • Patkó et al 2015, “Sneaky fe­lids, smelly scents: a small scale sur­vey for at­tract­ing cat”: wild sur­vey in Hun­gary, com­par­ing cat­nip with salmon oil/valerian/commercial-scent; 1 & 3 cats rubbed the cat­nip, 4 va­le­ri­an, none oth­er­wise.

  • Patkó et al 2016, “More Hair than Wit: A Re­view on Car­ni­vore Re­lated Hair Col­lect­ing Meth­ods”: lit­er­a­ture re­view on wild sur­vey­ing; no par­tic­u­lar con­clu­sions drawn on cat­nip.

  • Crow­ley & Hod­der 2017, “An as­sess­ment of the effi­cacy of rub sta­tions for de­tec­tion and abun­dance sur­veys of Canada lynx (Lynx canaden­sis)”: a wild sur­vey; the lynx did use both the beaver cas­tor & cat­nip oil rub sta­tions but, like Mc­Daniel et al 2000, the method does not per­mit any quan­tifi­ca­tion of re­sponse rates in the Canada lynx al­though the au­thors in­fer it was <100% since the cat­nip oil rub sta­tions did not work as well as the stan­dard .

  • Shreve et al 2017, “So­cial in­ter­ac­tion, food, scent or toys? A for­mal as­sess­ment of do­mes­tic pet and shel­ter cat (Fe­lis sil­vestris catus) pref­er­ences”: ex­per­i­men­tal test of 25 pet & 25 an­i­mal shel­ter cats’ pref­er­ences by offer­ing the stim­uli si­mul­ta­ne­ously and mea­sur­ing pro­por­tion of time on each to ex­tract a “choice”; for ex­am­ple, in the ol­fac­tory cat­e­go­ry, of the 38 cats, 6 ‘chose’ the ger­bil, 6 the cloth rubbed on an­other cat’s scent glands (“con­spe­cific”), and 22 the cat­nip. How­ev­er, while may look like a plau­si­ble es­ti­mate of cat­nip re­sponse in this sam­ple, that would be mak­ing some strong as­sump­tions, as Shreve et al do not men­tion try­ing to clas­sify cat­nip re­spon­se, and the choice is am­bigu­ous: 22 of 38 cats find­ing cat­nip the most in­ter­est­ing smell does not mean 22 had a cat­nip re­sponse - as any of the 22 might not have had a re­sponse but sim­ply found the cat­nip a more pleas­ing or novel smell, and vice versa for the oth­er.

  • Bol et al 2017, : one of the most thor­ough stud­ies, us­ing both a large num­ber of cats (n = 100) and the 4 ma­jor cat stim­u­lants, Bol et al 2017 is an im­pres­sive ex­per­i­ment. It’s worth high­light­ing that the 4 stim­u­lants were offered to the same set of cats, al­low­ing mea­sure­ment of in­ter­cor­re­la­tions, cats were ex­posed at least twice with at­ten­tion given to a low-stress ad­min­is­tra­tion (re­duc­ing mea­sure­ment er­ror, as em­pha­sized by Vil­lani 2011), gas chro­matog­ra­phy was used for a chem­i­cal analy­sis, the sam­ple size is one of the largest ever (ex­ceeded only by Vil­lani 2011/Lyons 2013 and my sur­veys), the part­ner­ship with Big Cat Res­cue ex­tends the re­sults to sev­eral other in­ter­est­ing species (bob­cats & tiger­s), and the full dataset is in­cluded with the pa­per.

    I ex­tract 2 CSVs from the raw data, for cats & bobcats/tigers. Code re­sponses of “5” or “10” (mild vs in­tense) are con­sid­ered re­spon­ders; Bol states that “Be­cause most (80–90%) of the cats stud­ied were (blends of) do­mes­tic short­-haired breeds, we did not study as­so­ci­a­tions be­tween breed and re­spon­sive­ness to the ma­te­ri­als tested”, so the cats are all coded as “Amer­i­can short­-hair” breeds. Test­ing was done in the USA. Tigers/bobcats were like­wise coded as re­spon­ders if they had “5”/“10” codes for cat­nip. Sum­ma­ry:

    • 22⁄34 male cats re­sponded
    • 38⁄55 fe­male cats re­sponded
    • 2 male tigers, both non-re­spon­ders
    • 7 fe­male tigers, 1 re­spon­der
    • 1 fe­male bob­cat, 1 re­spon­der
  • Es­pín-I­turbe et al 2017, “Ac­tive and pas­sive re­sponses to cat­nip (Nepeta cataria) are affected by age, sex and early go­nadec­tomy in male and fe­male cats”

    Es­pín-I­turbe et al 2017 ar­gues (fol­low­ing Hill et al 1976) that cat­nip re­sponse has been wrongly con­ceived as an ac­tive or non-re­spon­der (base­line) bi­na­ry, and “non-re­spon­ders” are in fact re­spond­ing in a differ­ent way by mov­ing much less & adopt­ing the “sphinx” pos­ture (based on com­put­er­ized scor­ing of video­tape in a cylin­dri­cal cham­ber after ex­po­sure to cat­nip). Their re­sults also sug­gest that old­er, male, and ear­ly-neutered cats are more pas­sive re­spon­ders. This would sug­gest cat­nip is a drug ca­pa­ble of both stim­u­lant and de­pres­sive effects, like nico­tine or mar­i­juana or al­co­hol (although cat­nip would not seem to de­pend on dose, only in­di­vid­ual differ­ences).

  • Beck et al 2018, “Effect of a Syn­thetic Fe­line Pheromone for Man­ag­ing Un­wanted Scratch­ing”: com­mer­cial study which in­cluded 0.1% cat­nip in an­ti-scratch­ing so­lu­tion prod­uct with re­port­edly good re­sults, but effect is con­founded and can’t in­fer in­di­vid­ual cat re­sponse rates

  • Can­nas et al 2018, “Effect of a Nepeta cataria oil diffu­sor on cat be­hav­iour”: pa­per in Ital­ian; Eng­lish ab­stract in­di­cates it was a n = 20 (10/10) be­tween-group study of a cat­nip es­sen­tial oil aro­matic diffuser; re­sults:

    Based on owner an­swers, 90% [9⁄10] of cats of the ther­apy group and 40% [4⁄10] of cats of the con­trol group showed an im­prove­ment (p≤0.05). Play be­hav­iour in­creased in the ther­apy group and de­crease in the con­trol one (p = 0.06). The per­cent­age of cats show­ing hiss­ing or bit­ing at­tempts to­ward other cats and scratch­ing doors de­creased sig­nifi­cantly in the ther­apy group (p≤0.05) and in­creased in the con­trol one. Sim­i­lar trend was seen for cats chang­ing room to go away from other an­i­mals and we found a sta­tis­ti­cal differ­ence be­tween the two groups be­fore (p≤0.05) and post-treat­ment (p = 0.081).

    Given the con­sid­er­able im­prove­ment in the con­trol group, the 9⁄10 can’t be in­ter­preted as a re­sponse rate. If we sub­tract the con­trol group’s 4⁄10 as a base­line for re­gres­sion to the mean or own­er-place­bo-effect, the 5⁄10 is a plau­si­ble re­sult for cat­nip re­spon­se, but is in­di­rect enough that I think it’s prob­a­bly bet­ter to leave it out of the meta-analy­sis.

  • Bir­kett et al 2011, “Re­pel­lent ac­tiv­ity of cat­mint, Nepeta cataria, and iri­doid nepeta­lac­tone iso­mers against Afro-trop­i­cal mos­qui­toes, ixo­did ticks and red poul­try mites”; al­though this is not de­scribed any­where in the text of Bir­kett et al 2011, ac­cord­ing to Sharma et al 2019:

    Bir­kett et al. (2011) syn­the­sized the un­nat­ural (4aR,7R,7aS)-nepeta­lac­tone and enan­tiomer of (4aS,7S,7aR)-nepeta­lac­tone. These two mol­e­cules have been bioas­sayed against two Amer­i­can short­-hair, three Abyssini­an, and four Japan­ese cats. Al­most all cats re­acted strongly es­pe­cially the fe­male ones to­wards both the enan­tiomers. Fe­male cats have been found to be ex­tremely at­trac­tive even at the dose of 0.01 mg.

    Sharma et al 2019 seems to have ei­ther omit­ted a ci­ta­tion or con­fused Bir­kett et al 2011 with Saku­rai et al 1988.

  • Jean-Louis 2019, “Effect of sen­sory en­rich­ments on the be­hav­iour of cap­tive North­ern lynx (Lynx lynx lynx) and as­sess­ment of au­to­mated be­hav­iour mon­i­tor­ing tech­nolo­gies”:

    Tested catnip/valerian/cinnamon on 3 lynx­es. Cat­nip re­sulted in sub­stan­tially more in­ter­ac­tion, but Jean-Louis 2019 an­a­lyzes & vi­su­al­izes only by to­tals, not break­ing it down by lynx, so no es­ti­mate of whether it’s 1/2/3 re­spon­ders is pos­si­ble.


Po­ten­tially rel­e­vant but cur­rently un­avail­able:

  • Lyons 2013, “Genome-Wide As­so­ci­a­tion Study for Cat­nip Re­sponse in Do­mes­tic Cats”: un­pub­lished re­search, but ab­stract of re­sults; TODO: email Leslie Lyons and ask if pub­lished any­where or if the dataset can be made pub­lic; the cat­nip re­sponse rate would be in­for­ma­tive, there may be other ge­netic analy­ses, and would boost any fu­ture GWAS:

    Re­sults: No Sig­nifi­cant Ge­netic Re­gion Iden­ti­fied for Cat­nip Re­sponse in Cats. About 50% of cats re­spond to cat­nip. Funded by the Cat Health Net­work, re­searchers from the Uni­ver­sity of Cal­i­for­ni­a–­Davis tested 192 shel­ter cats for cat­nip re­sponse in con­trolled set­tings. DNA was col­lected from cats re­spond­ing to cat­nip and com­pared to DNA of non­re­spond­ing cats. Ge­netic analy­sis of these sam­ples did not re­veal a causative gene as­so­ci­ated with cat­nip re­sponse. Iden­ti­fi­ca­tion of genes re­spon­si­ble for cat­nip re­sponse may pro­vide clues to the mech­a­nisms in­volved in ol­fac­tory re­sponses to drugs and chem­i­cals in cats.

Over­all, study qual­ity is low and at high risk of bias. Key vari­ables like sex/age/breed is al­most al­ways never re­ported and some­times even n or species is not re­port­ed; placebo con­trols are not used; the ex­per­i­menters are never blind to the sub­stance be­ing used; im­por­tant stud­ies are not avail­able in Eng­lish; the cat­nip used is not stan­dard­ized; and the an­i­mals are not nec­es­sar­ily fa­mil­iar­ized & com­fort­able with the ex­per­i­menter de­spite the need for them to be re­laxed and will­ing to play in or­der to gauge the pres­ence or ab­sence of a re­sponse. Prob­a­bly any es­ti­mate is some­thing of a lower bound as most of these bi­ases would tend to mask a cat­nip re­sponse (like us­ing old cat­nip or an an­i­mal feel­ing stressed), and it will be diffi­cult to prove or dis­prove any sex or breed effects.


catnip <- read.csv(stdin(), header=TRUE)
Family,Genus,Species,Name,Study, Year, Responders, N, Country, Sex, Breed
Felidae,Panthera,leo,African lion,McElvain et al 1942,1942,7,7,USA,mixed,NA
Viverrinae,Civettictis,NA,NA,Todd 1962,1962,0,3,USA,mixed,NA
Viverrinae,Viverra,NA,NA,Todd 1962,1962,0,1,USA,mixed,NA
Viverrinae,Civettictis,NA,NA,Todd 1962,1962,0,2,USA,mixed,NA
Paradoxurinae,Nandinia,NA,NA,Todd 1962,1962,0,5,USA,mixed,NA
Paradoxurinae,Paguma,NA,NA,Todd 1962,1962,0,2,USA,mixed,NA
Paradoxurinae,Arctictis,NA,NA,Todd 1962,1962,2,3,USA,mixed,NA
Herpestinae,Herpestes,NA,NA,Todd 1962,1962,0,1,USA,mixed,NA
Herpestinae,Atilax,NA,NA,Todd 1962,1962,1,3,USA,mixed,NA
Herpestinae,Ichneumia,NA,NA,Todd 1962,1962,0,1,USA,mixed,NA
Cryptoproctinae,Cryptoprocta,NA,NA,Todd 1962,1962,0,1,USA,mixed,NA
Hyaenidae,NA,NA,hyena,Todd 1962,1962,0,1,USA,F,NA
Hyaenidae,NA,NA,hyena,Todd 1962,1962,0,2,USA,M,NA
Felidae,Panthera,leo,African lion,Todd 1962,1962,6,6,USA,M,NA
Felidae,Panthera,leo,African lion,Todd 1962,1962,8,10,USA,F,NA
Felidae,Panthera,tigris,tiger,Todd 1962,1962,1,9,USA,M,NA
Felidae,Panthera,tigris,tiger,Todd 1962,1962,7,13,USA,F,NA
Felidae,Panthera,leo/tigris,ligeress,Todd 1962,1962,0,1,USA,F,NA
Felidae,Panthera,pardus,leopard,Todd 1962,1962,6,8,USA,M,NA
Felidae,Panthera,pardus,leopard,Todd 1962,1962,8,10,USA,F,NA
Felidae,Panthera,onca,jaguar,Todd 1962,1962,4,5,USA,M,NA
Felidae,Panthera,onca,jaguar,Todd 1962,1962,3,3,USA,F,NA
Felidae,Panthera,uncia,snow leopard,Todd 1962,1962,2,2,USA,M,NA
Felidae,Panthera,uncia,snow leopard,Todd 1962,1962,2,2,USA,F,NA
Felidae,Neofelis,nebulosa,clouded leopard,Todd 1962,1962,1,2,USA,NA,NA
Felidae,Acinonyx,jubatus,cheetah,Todd 1962,1962,0,3,USA,NA,NA
Felidae,Felis,rufus,bobcat,Todd 1962,1962,1,2,USA,NA,NA
Felidae,Felis,lynx,European lynx,Todd 1962,1962,1,1,USA,NA,NA
Felidae,Felis,concolor,puma,Todd 1962,1962,2,3,USA,M,NA
Felidae,Felis,concolor,puma,Todd 1962,1962,1,2,USA,F,NA
Felidae,Felis,temmincki,African golden cat,Todd 1962,1962,1,1,USA,NA,NA
Felidae,Felis,aurata,Asian golden cat,Todd 1962,1962,0,1,USA,NA,NA
Felidae,Felis,pardalis,ocelot,Todd 1962,1962,4,5,USA,NA,NA
Felidae,Felis,wiedii,margay,Todd 1962,1962,4,6,USA,NA,NA
Felidae,Felis,serval,serval,Todd 1962,1962,0,2,USA,NA,NA
Felidae,Felis,chaus,swamp cat,Todd 1962,1962,0,1,USA,NA,NA
Felidae,Felis,manul,Pallas cat,Todd 1962,1962,0,1,USA,NA,NA
Felidae,Felis,bengalensis,leopard cat,Todd 1962,1962,0,1,USA,NA,NA
Felidae,Felis,viverrina,fishing cat,Todd 1962,1962,0,2,USA,NA,NA
Felidae,Felis,yagouaroundi,jaguarundi,Todd 1962,1962,0,4,USA,NA,NA
Felidae,Felis,pajeros,pampas cat,Todd 1962,1962,0,1,USA,NA,NA
Felidae,Felis,catus,cat,Todd 1962,1962,8,10,USA,M,Siamese
Felidae,Felis,catus,cat,Todd 1962,1962,6,16,USA,F,Siamese
Felidae,Felis,catus,cat,Todd 1963,1963,32,43,USA,M,mixed
Felidae,Felis,catus,cat,Todd 1963,1963,26,41,USA,F,mixed
Felidae,Felis,catus,cat,Bates & Siegel 1963,1963,5,8,USA,NA,NA
Felidae,Felis,catus,cat,Palen & Goddard 1966,1966,15,26,USA,M,mixed
Felidae,Felis,catus,cat,Palen & Goddard 1966,1966,8,17,USA,F,mixed
Felidae,Felis,catus,cat,Hayashi 1968,1966,1,2,USA,NA,NA
Felidae,Felis,catus,cat,Hayashi 1968,1966,1,2,UK,NA,NA
Felidae,Felis,catus,cat,Hayashi 1968,1966,2,2,Japan,NA,NA
Canidae,Canis,lupus,dog,Hayashi 1968,1966,0,2,Japan,NA,NA
Leporidae,Oryctolagus,cuniculus,rabbit,Hayashi 1968,1966,0,2,Japan,NA,NA
Muridae,Mus,musculus,mouse,Hayashi 1968,1966,0,2,Japan,NA,NA
Muridae,Rattus,norvegicus,rat,Hayashi 1968,1966,0,2,Japan,NA,NA
Caviidae,Cavia,porcellus,guinea pig,Hayashi 1968,1966,0,2,Japan,NA,NA
Phasianidae,NA,NA,fowl,Hayashi 1968,1966,0,2,Japan,NA,NA
Felidae,Felis,catus,cat,Hatch 1972,1972,14,17,USA,mixed,mixed
Felidae,Panthera,leo,African lion,Hill et al 1976,1976,3,4,USA,M,NA
Felidae,Panthera,leo,African lion,Hill et al 1976,1976,5,5,USA,F,NA
Felidae,Panthera,onca,jaguar,Hill et al 1976,1976,1,1,USA,M,NA
Felidae,Panthera,onca,jaguar,Hill et al 1976,1976,2,2,USA,F,NA
Felidae,Panthera,pardus,leopard,Hill et al 1976,1976,2,4,USA,M,NA
Felidae,Panthera,pardus,leopard,Hill et al 1976,1976,2,4,USA,F,NA
Felidae,Panthera,tigrus,tiger,Hill et al 1976,1976,0,1,USA,M,NA
Felidae,Panthera,tigrus,tiger,Hill et al 1976,1976,0,4,USA,F,NA
Felidae,Felis,rufus,bobcat,Hill et al 1976,1976,0,1,USA,M,NA
Felidae,Felis,rufus,bobcat,Hill et al 1976,1976,0,1,USA,F,NA
Felidae,Puma,concolor,cougar,Hill et al 1976,1976,0,2,USA,M,NA
Felidae,Puma,concolor,cougar,Hill et al 1976,1976,0,2,USA,F,NA
Felidae,Felis,catus,cat,Sakurai et al 1988,1988,4,4,Japan,mixed,Japanese
Felidae,Felis,catus,cat,Sakurai et al 1988,1988,3,3,Japan,mixed,Abyssinian
Felidae,Felis,catus,cat,Sakurai et al 1988,1988,2,2,Japan,mixed,American short-hair
Felidae,Felis,catus,cat,Sakurai et al 1988,1988,16,16,Japan,NA,Japanese
Felidae,Felis,catus,cat,DeLuca & Kranda 1992,1992,6,10,USA,NA,mixed
Felidae,Felis,catus,cat,Clapperton et al 1994,1994,12,24,USA,NA,mixed
Felidae,Felis,concolor,puma,Portella et al 2013,2013,0,6,USA,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,695,842,Canada,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,615,783,USA,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,463,625,UK,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,228,320,Japan,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,216,380,Germany,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,174,313,Brazil,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,108,200,Spain,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,403,759,Australia,NA,NA
Felidae,Felis,catus,cat,Gwern 2017,2017,94,180,Mexico,NA,NA
Felidae,Felis,catus,cat,Bol et al 2017,2017,22,34,USA,M,American short-hair
Felidae,Felis,catus,cat,Bol et al 2017,2017,38,55,USA,F,American short-hair
Felidae,Felis,catus,cat,Bol et al 2017,2017,7,10,USA,NA,American short-hair
Felidae,Panthera,tigrus,tiger,Bol et al 2017,2017,1,7,USA,F,NA
Felidae,Panthera,tigrus,tiger,Bol et al 2017,2017,0,2,USA,M,NA
Felidae,Felis,rufus,bobcat,Bol et al 2017,2017,1,1,USA,F,NA

catnip$Sex <- ordered(catnip$Sex, levels=c("F", "mixed", "M"))
catnip$Country <- relevel(catnip$Country, "USA")


Cats catnip response rate

A ran­dom-effects meta-analy­sis on the pro­por­tion of cat­nip re­sponse in do­mes­tic cats us­ing metafor:

cat <- subset(catnip, Name=="cat")
sum(cat$Responders) / sum(cat$N)
# [1] 0.6795952782

r <- rma(xi=Responders, ni=N, measure="PR", slab=Study, data=cat); summary(r)
# Random-Effects Model (k = 29; tau^2 estimator: REML)
#   logLik  deviance       AIC       BIC      AICc
#  12.0648  -24.1296  -20.1296  -17.4652  -19.6496
# tau^2 (estimated amount of total heterogeneity): 0.0155 (SE = 0.0059)
# tau (square root of estimated tau^2 value):      0.1244
# I^2 (total heterogeneity / total variability):   92.25%
# H^2 (total variability / sampling variability):  12.90
# Test for Heterogeneity:
# Q(df = 28) = 382.1487, p-val < .0001
# Model Results:
# estimate      se     zval    pval   ci.ub
#   0.6714  0.0288  23.3059  <.0001  0.6150  0.7279

png(file="~/wiki/images/catnip/catnip-forest.png", width = 590, height = 610)
forest(r, xlim=c(0,1))

## some issues in the funnel plot of too-extreme values:
funnel(r); trimfill(r)
# ...Estimated number of missing studies on the right side: 0 (SE = 3.3070)

## Examine all moderators:
rall <- rma(xi=Responders, ni=N, measure="PR", slab=Study,
            mods= ~ Year + Country + Sex + Breed, data=cat)
# Mixed-Effects Model (k = 12; tau^2 estimator: REML)
#   logLik  deviance       AIC       BIC      AICc
#   1.8566   -3.7133   16.2867    7.2728  236.2867
# tau^2 (estimated amount of residual heterogeneity):     0.0058 (SE = 0.0114)
# tau (square root of estimated tau^2 value):             0.0763
# I^2 (residual heterogeneity / unaccounted variability): 42.11%
# H^2 (unaccounted variability / sampling variability):   1.73
# R^2 (amount of heterogeneity accounted for):            16.14%
# Test for Residual Heterogeneity:
# QE(df = 3) = 5.3993, p-val = 0.1448
# Test of Moderators (coefficient(s) 2:9):
# QM(df = 8) = 10.3723, p-val = 0.2399
# Model Results:
#                           estimate       se     zval    pval     ci.ub
# intrcpt                   112.4174  80.1102   1.4033  0.1605  -44.5957  269.4304
# Year                       -0.0553   0.0397  -1.3935  0.1635   -0.1330    0.0225
# CountryJapan               -2.0805   1.4876  -1.3986  0.1619   -4.9961    0.8351
# Sex.L                       0.0799   0.0592   1.3497  0.1771   -0.0361    0.1960
# Sex.Q                      -0.5159   0.2766  -1.8651  0.0622   -1.0581    0.0263
# BreedAmerican short-hair   -0.0417   0.2920  -0.1427  0.8865   -0.6141    0.5307
# BreedJapanese               0.0250   0.2387   0.1047  0.9166   -0.4429    0.4929
# Breedmixed                 -3.0163   2.1190  -1.4235  0.1546   -7.1695    1.1369
# BreedSiamese               -3.1782   2.2048  -1.4414  0.1495   -7.4996    1.1433

r_country <- rma(xi=Responders, ni=N, measure="PR", slab=Study,
            mods= ~ Country, data=cat)
# Mixed-Effects Model (k = 29; tau^2 estimator: REML)
#   logLik  deviance       AIC       BIC      AICc
#  10.7309  -21.4619   -1.4619    8.4954   22.9826
# tau^2 (estimated amount of residual heterogeneity):     0.0096 (SE = 0.0061)
# tau (square root of estimated tau^2 value):             0.0978
# I^2 (residual heterogeneity / unaccounted variability): 63.38%
# H^2 (unaccounted variability / sampling variability):   2.73
# R^2 (amount of heterogeneity accounted for):            38.23%
# Test for Residual Heterogeneity:
# QE(df = 20) = 67.8909, p-val < .0001
# Test of Moderators (coefficient(s) 2:9):
# QM(df = 8) = 19.6513, p-val = 0.0117
# Model Results:
#                   estimate      se     zval    pval   ci.ub
# intrcpt             0.6581  0.0365  18.0326  <.0001   0.5866  0.7297
# CountryAustralia   -0.1272  0.1059  -1.2006  0.2299  -0.3348  0.0804
# CountryBrazil      -0.1022  0.1081  -0.9458  0.3442  -0.3141  0.1096
# CountryCanada       0.1673  0.1052   1.5902  0.1118  -0.0389  0.3734
# CountryGermany     -0.0897  0.1074  -0.8352  0.4036  -0.3003  0.1208
# CountryJapan        0.1889  0.0695   2.7186  0.0066   0.0527  0.3250
# CountryMexico      -0.1359  0.1108  -1.2265  0.2200  -0.3531  0.0813
# CountrySpain       -0.1181  0.1102  -1.0724  0.2835  -0.3341  0.0978
# CountryUK           0.0662  0.1026   0.6453  0.5188  -0.1349  0.2673

r_year <- rma(xi=Responders, ni=N, measure="PR", slab=Study,
            mods= ~ Year + Country, data=cat)
# Mixed-Effects Model (k = 29; tau^2 estimator: REML)
#   logLik  deviance       AIC       BIC      AICc
#   9.8005  -19.6011    2.3989   12.7878   40.1132
# tau^2 (estimated amount of residual heterogeneity):     0.0104 (SE = 0.0068)
# tau (square root of estimated tau^2 value):             0.1022
# I^2 (residual heterogeneity / unaccounted variability): 60.97%
# H^2 (unaccounted variability / sampling variability):   2.56
# R^2 (amount of heterogeneity accounted for):            32.52%
# Test for Residual Heterogeneity:
# QE(df = 19) = 66.6594, p-val < .0001
# Test of Moderators (coefficient(s) 2:10):
# QM(df = 9) = 18.5649, p-val = 0.0292
# Model Results:
#                   estimate      se     zval    pval   ci.ub
# intrcpt            -0.6080  2.7891  -0.2180  0.8274  -6.0745  4.8585
# Year                0.0006  0.0014   0.4536  0.6501  -0.0021  0.0034
# CountryAustralia   -0.1455  0.1184  -1.2286  0.2192  -0.3775  0.0866
# CountryBrazil      -0.1205  0.1203  -1.0016  0.3165  -0.3563  0.1153
# CountryCanada       0.1490  0.1177   1.2656  0.2057  -0.0818  0.3797
# CountryGermany     -0.1080  0.1197  -0.9021  0.3670  -0.3427  0.1267
# CountryJapan        0.1845  0.0728   2.5331  0.0113   0.0417  0.3272
# CountryMexico      -0.1542  0.1228  -1.2559  0.2091  -0.3948  0.0864
# CountrySpain       -0.1364  0.1222  -1.1165  0.2642  -0.3759  0.1031
# CountryUK           0.0491  0.1131   0.4339  0.6644  -0.1725  0.2706

## moderately informative Bayesian meta-analysis
## (bayesmeta doesn't support moderators/meta-regression, so estimate just mean/SD):
b <- bayesmeta(y = escalc(xi=Responders, ni=N, measure="PR", data=cat),
               mu.prior.mean=0.5,; summary(b)
# ...marginal posterior summary:
#                     tau           mu        theta
# mode      0.12487373717 0.6583157958 0.6588646213
# median    0.13029833512 0.6573472098 0.6575484257
# mean      0.13317030042 0.6568159715 0.6568159715
# sd        0.02521684197 0.0295391439 0.1389217521
# 95% lower 0.08801259311 0.5980530543 0.3796963066
# 95% upper 0.18372308609 0.7145549723 0.9312941009
# (quoted intervals are shortest credibility intervals.)
# relative heterogeneity I^2 (posterior median): 0.9288449557
Meta-an­a­lytic for­est plot of cat­nip re­sponse rates in ex­per­i­men­tal stud­ies

The 2⁄3 rule of thumb proves to be about right, with a meta-an­a­lytic sum­mary of ~67% cat­nip re­sponse rates.

The het­ero­gene­ity of the re­sults in­di­cates that some­things are differ­ent from study to study or that bi­ases like pub­li­ca­tion bias are at play; in­clud­ing the sex and breed co­vari­ates does­n’t help much be­cause of the miss­ing data, but there’s in­ter­est­ing trends of de­creases with a study be­ing con­ducted later in time.

The sus­pi­cious Saku­rai 16⁄16 dat­a­point does­n’t show up in the full model be­cause it has no sex in­for­ma­tion and gets dropped, so the Japan­ese trend there is be­ing dri­ven by the other Saku­rai dat­a­points; the Hayashi re­sults fur­ther sup­port the Japan­ese anom­aly. With ad­di­tional data from my large-s­cale Google Sur­veys, the Japan­ese anom­aly washes out: Japan does re­main one of the high­est cat­nip re­sponse coun­try but looks much more rea­son­able, with a cat­nip re­sponse rate sim­i­lar to Cana­da.

The de­crease with time ini­tially ob­served is odd in the full mod­el, but it seems to be dis­ap­pear­ing as ad­di­tional stud­ies are con­duct­ed, and it’s much more likely that it’s re­flect­ing early differ­ences in ex­per­i­men­tal pro­ce­dure or breeds or coun­tries than in­di­cat­ing that cat­nip re­sponse rates are be­ing heav­ily se­lected against3, es­pe­cially as the de­crease with time dis­ap­pears en­tirely if I en­sure the 2017 sur­veys are in­cluded (rather than dropped for lack of sex/breed in­for­ma­tion).

Over­all, the data qual­ity is low as many au­thors (e­spe­cially the early chemists) did not re­port in­di­vid­ual re­sponse rates or key de­tails of the cats used such as their age, breed, or sex, which is par­tic­u­larly un­for­tu­nate as all the sam­ples are small enough that the orig­i­nal data could’ve been eas­ily in­cluded as short ta­bles. This is ironic be­cause while some au­thors claim that sex/breed does­n’t mat­ter at all, oth­ers claim that fe­males re­act much more strongly (or was it males?), and yet most don’t re­port the data down by those vari­ables, so their re­sults can’t be pooled for an an­swer.

Cross-species catnip response rates

Cat­nip has been tested in a num­ber of species. It would be in­ter­est­ing to in­clude this data for sev­eral rea­sons: it can help the search for the ge­netic ba­sis by com­par­ing cat­nip-sen­si­tive species with non-sen­si­tive look­ing for ge­netic vari­ants pe­cu­liar to the for­mer, or if there is no ap­par­ent clus­ter of close­ly-re­lated species which uniquely have cat­nip re­spons­es, it can test the­o­ries about what lo­cal en­vi­ron­ments might cause cat­nip sen­si­tiv­i­ty; it can po­ten­tially help sharpen es­ti­mates of sex/age/country/experimenter effects by ‘bor­row­ing strength’; zookeep­ers can en­rich their an­i­mals’ lives with cat­nip if they know which species re­spond; and since the data is al­ready there in the pa­pers, we might as well in­clude it.

To ex­am­ine cross-species trends, we would like to fit a mul­ti­level model us­ing family/genus/species, since one would ex­pect the cat­nip re­sponse rate to be more sim­i­lar be­tween, say, African li­ons & tigers than be­tween snow leop­ards & hye­nas. Since each species might have differ­ent gen­der effects and pop­u­la­tion bot­tle­necks, we would ide­ally nest in each species the sex/country/breed/year co­vari­ates. We would also like in­de­pen­dent ran­dom-effects for each study to al­low for the het­ero­gene­ity we ob­served be­fore (which could be in­de­pen­dent of the family/genus/species hi­er­ar­chy, in which case it would model things like differ­ent ex­per­i­men­tal pro­ce­dures - eg cat­nip leaves vs ex­tract, or the ex­per­i­menter be­ing good or bad with an­i­mals - or it could be species-spe­cific too). Un­for­tu­nate­ly, such a full model would re­quire es­ti­mat­ing a huge num­ber of pa­ra­me­ters (with 24 species, 14 genus­es, & 6 fam­i­lies, 10 stud­ies, and 4 vari­ables for each species, that’s eas­ily 270 pa­ra­me­ters which must be fit) and there is too lit­tle data (and the avail­able data is com­pro­mised by the fre­quent miss­ing­ness of species and sex), so we have to set­tle for some­thing more mod­est, fo­cus­ing on just the cross-species as­pect.

## full model is unidentifiable due to too few data points and missingness:
# b <- bglmer(cbind(Responders, N) ~ (Sex+Country+Breed+Year|Species/Genus/Family) + (1|Study), family="binomial", data=catnip)

# levels(catnip$Name) <- c(levels(catnip$Name), as.character(catnip[$Name),]$Genus))
# catnip[$Name),]$Name <- as.character(catnip[$Name),]$Genus)
## sort by taxonomy:
catnip <- catnip[with(catnip, order(Family, Genus, Species)),]
catnip$Label <- with(catnip, Map(function(f,g,s, n) { paste0(n, " (", paste(f, g, s), ")") }, Family, Genus, Species, Name))

cross <- rma(xi=Responders, ni=N, measure="PR", slab=Label,
            mods = ~ Species, data=catnip)
# Mixed-Effects Model (k = 79; tau^2 estimator: REML)
#   logLik  deviance       AIC       BIC      AICc
#  18.1500  -36.2999   23.7001   81.0608  121.5948
# tau^2 (estimated amount of residual heterogeneity):     0.0130 (SE = 0.0048)
# tau (square root of estimated tau^2 value):             0.1141
# I^2 (residual heterogeneity / unaccounted variability): 85.31%
# H^2 (unaccounted variability / sampling variability):   6.81
# R^2 (amount of heterogeneity accounted for):            73.68%
# Test for Residual Heterogeneity:
# QE(df = 50) = 399.0507, p-val < .0001
# Test of Moderators (coefficient(s) 2:29):
# QM(df = 28) = 114.5476, p-val < .0001
# Model Results:
#                      estimate      se     zval    pval   ci.ub
# intrcpt                0.2500  0.3267   0.7651  0.4442  -0.3904  0.8904
# Speciesbengalensis     0.0000  0.4621   0.0000  1.0000  -0.9057  0.9057
# Speciescatus           0.4215  0.3279   1.2857  0.1986  -0.2211  1.0641
# Specieschaus           0.0000  0.4621   0.0000  1.0000  -0.9057  0.9057
# Speciesconcolor       -0.0429  0.3422  -0.1253  0.9003  -0.7135  0.6278
# Speciescuniculus      -0.0833  0.4075  -0.2045  0.8380  -0.8821  0.7154
# Speciesjubatus        -0.1250  0.3836  -0.3259  0.7445  -0.8768  0.6268
# Speciesleo             0.6381  0.3350   1.9048  0.0568  -0.0185  1.2946
# Speciesleo/tigris      0.0000  0.4621   0.0000  1.0000  -0.9057  0.9057
# Specieslupus          -0.0833  0.4075  -0.2045  0.8380  -0.8821  0.7154
# Specieslynx            0.5000  0.4621   1.0820  0.2792  -0.4057  1.4057
# Speciesmanul           0.0000  0.4621   0.0000  1.0000  -0.9057  0.9057
# Speciesmusculus       -0.0833  0.4075  -0.2045  0.8380  -0.8821  0.7154
# Speciesnebulosa        0.2500  0.4947   0.5053  0.6133  -0.7197  1.2197
# Speciesnorvegicus     -0.0833  0.4075  -0.2045  0.8380  -0.8821  0.7154
# Speciesonca            0.5767  0.3470   1.6618  0.0966  -0.1035  1.2568
# Speciespajeros         0.0000  0.4621   0.0000  1.0000  -0.9057  0.9057
# Speciespardalis        0.5500  0.3896   1.4118  0.1580  -0.2136  1.3136
# Speciespardus          0.4446  0.3436   1.2938  0.1957  -0.2289  1.1181
# Speciesporcellus      -0.0833  0.4075  -0.2045  0.8380  -0.8821  0.7154
# Speciesrufus           0.1837  0.3675   0.5000  0.6171  -0.5365  0.9040
# Speciesserval         -0.0833  0.4075  -0.2045  0.8380  -0.8821  0.7154
# Speciestemmincki       0.5000  0.4621   1.0820  0.2792  -0.4057  1.4057
# Speciestigris          0.0438  0.3471   0.1261  0.8996  -0.6366  0.7241
# Speciestigrus         -0.1069  0.3431  -0.3115  0.7554  -0.7794  0.5656
# Speciesuncia           0.5833  0.3693   1.5794  0.1143  -0.1406  1.3072
# Speciesviverrina      -0.0833  0.4075  -0.2045  0.8380  -0.8821  0.7154
# Specieswiedii          0.4167  0.3960   1.0522  0.2927  -0.3595  1.1928
# Speciesyagouaroundi   -0.1500  0.3712  -0.4041  0.6861  -0.8775  0.5775

png(file="~/wiki/images/catnip/catnip-forest-crossspecies.png", width = 580, height = 1600)

b <- bglmer(cbind(Responders, N) ~ (1|Species/Genus/Family) + (1|Study) + Year, family="binomial", data=catnip)
summary(b); ranef(b)
For­est plot of cat­nip re­sponses across all sam­pled species


In com­pil­ing a meta-analy­sis of re­ports of , yield­ing an meta-an­a­lytic av­er­age of ~2⁄3, the avail­able data sug­gests het­ero­gene­ity from cross-coun­try differ­ences in rates (pos­si­bly for ge­netic rea­sons) but is in­suffi­cient to de­fin­i­tively demon­strate the ex­is­tence of or es­ti­mate those differ­ences (par­tic­u­larly a pos­si­ble ex­tremely high cat­nip re­sponse rate in Japan). I use Google Sur­veys Au­gust-Sep­tem­ber 2017 to con­duct a brief 1-ques­tion on­line sur­vey of a pro­por­tional pop­u­la­tion sam­ple of 9 coun­tries about cat own­er­ship & cat­nip use, specifi­cal­ly: Canada, the USA, UK, Japan, Ger­many, Brazil, Spain, Aus­tralia, & Mex­i­co. in to­tal, I sur­veyed n = 31,471 peo­ple, of whom n = 9,087 are cat own­ers, of whom n = 4,402 re­port hav­ing used cat­nip on their cat, and of whom n = 2996 re­port a cat­nip re­sponse.

The sur­vey yields cat­nip re­sponse rates of Canada (82%), USA (79%), UK (74%), Japan (71%), Ger­many (57%), Brazil (56%), Spain (54%), Aus­tralia (53%), and Mex­ico (52%). The differ­ences are sub­stan­tial and of high pos­te­rior prob­a­bil­i­ty, sup­port­ing the ex­is­tence of large cross-coun­try differ­ences. In ad­di­tional analy­sis, the other con­di­tional prob­a­bil­i­ties of cat own­er­ship and try­ing cat­nip with a cat ap­pear to cor­re­late with cat­nip re­sponse rates; this in­ter­cor­re­la­tion sug­gests a “cat fac­tor” of some sort in­flu­enc­ing re­spons­es, al­though what causal re­la­tion­ship there might be be­tween pro­por­tion of cat own­ers and pro­por­tion of cat­nip-re­spon­der cats is un­clear.

An ad­di­tional sur­vey of a con­ve­nience sam­ple of pri­mar­ily US In­ter­net users about cat­nip is re­port­ed, al­though the im­prob­a­ble cat­nip re­sponse rates com­pared to the pop­u­la­tion sur­vey sug­gest the re­spon­dents are ei­ther highly un­rep­re­sen­ta­tive or the ques­tions caused de­mand bias.

Main ar­ti­cle:

Optimal catnip alternative selection: solving the MDP

Bol et al 2017 tested 4 cat stim­u­lants on a large (n > 100) sam­ple of cats, yield­ing with­in-in­di­vid­ual cor­re­la­tions of stim­u­lant re­spons­es. This al­lows pre­dic­tion of stim­u­lant re­sponse con­di­tional on ob­serv­ing other stim­u­lant re­spons­es. I use this to demon­strate how to op­ti­mize stim­u­lant se­lec­tion as a se­quen­tial test­ing prob­lem, yield­ing (for one set of re­al­is­tic pur­chase costs) a test se­quence of cat­nip → hon­ey­suckle → sil­vervine → Va­le­ri­an, which is differ­ent from the greedy pol­icy of pick­ing stim­u­lants by prior prob­a­bil­i­ty.

Bol et al 2017, as not­ed, pro­vides re­sponses for 4 drugs (catnip/Valerian/silvervine/honeysuckle) in a large sam­ple of cats; re­sponses turn out to be heav­ily in­ter­cor­re­lat­ed, per­mit­ting the abil­ity to bet­ter pre­dict re­sponses to the cat­nip al­ter­na­tives based on a known re­sponse to one of the oth­ers. This be­comes use­ful if we treat it as a drug se­lec­tion prob­lem where we would like to find at least one work­ing drug for a cat while sav­ing mon­ey, and adapt­ing our next test based on failed pre­vi­ous tests.

If they were not in­ter­cor­re­lat­ed, one would sim­ply min­i­mize ex­pected loss in a greedy fash­ion, start­ing with cat­nip etc; but as they are in­ter­cor­re­lat­ed, now a drug has both di­rect value (if the cat re­sponds) and value of in­for­ma­tion (its fail­ure gives ev­i­dence about what other drugs that cat might re­spond to), which means the greedy pol­icy may no longer be the op­ti­mal pol­i­cy. The op­ti­mal se­quence can be de­rived by con­sid­er­ing all pos­si­ble se­quences of tests, up­dat­ing pre­dic­tions in a Bayesian fash­ion for each hy­po­thet­i­cal se­quence, cal­cu­lat­ing to­tal ex­pected losses based on the pos­te­rior prob­a­bil­i­ties, and min­i­miz­ing loss­es. For one set of costs and one cat re­sponse dataset, I de­rive an op­ti­mal se­quence of: cat­nip, hon­ey­suck­le, sil­vervine, and va­ler­ian. Im­ple­men­ta­tion be­low.

Load Bol et al 2017 for pre­dict­ing re­sponse to one drug based on re­sponses to oth­ers:

bol2017 <- read.csv("")
bol2017[,5:8] <- (bol2017[,5:8] > 0) # treat '5'/'10' (weak/strong response) as binary
bol2017Responses <- subset(bol2017, select=c("Catnip", "Valerian", "Silver.vine", "Tatarian.honeysuckle"))
colnames(bol2017Responses) <- c("Catnip", "Valerian", "Silvervine", "Honeysuckle") # rename for consistency
#...  variable missing complete   n mean                   count
#       Catnip       1       99 100 0.68 TRU: 67, FAL: 32, NA: 1
#  Honeysuckle       3       97 100 0.53 TRU: 51, FAL: 46, NA: 3
#   Silvervine       0      100 100 0.79 TRU: 79, FAL: 21, NA: 0
#     Valerian       4       96 100 0.47 FAL: 51, TRU: 45, NA: 4
# tetrachoric correlation
#             Catnp Valrn Slvrv Hnysc
# Catnip      1.00
# Valerian    0.60  1.00
# Silvervine  0.24  0.47  1.00
# Honeysuckle 0.43  0.35  0.23  1.00
#  with tau of
#      Catnip    Valerian  Silvervine Honeysuckle
#      -0.459       0.078      -0.806      -0.065

Greedy one-step pol­icy + sim­ple mar­ginal prob­a­bil­ity chooses a test se­quence of catnip/valerian/silvervine/honeysuckle:

Drug Cost P Loss
Cat­nip 8.96 0.67 2.9568
Va­ler­ian 7.00 0.47 3.7100
Sil­vervine 17.77 0.79 3.7317
Hon­ey­suckle 7.99 0.53 3.7553
costs <- read.csv(stdin(), header=TRUE, colClasses=c("character", "numeric"))

De­fine a cat­nip test­ing MDP: we are test­ing 4 cat drugs with in­ter­cor­re­lated re­spons­es, we want to find 1 drug which works, and we want to min­i­mize the mon­e­tary loss (s­ince we have to pay for each one as de­fined above). What is the op­ti­mal se­quence, which min­i­mizes ex­pected loss be­fore find­ing 1 work­ing drug? We can solve by back­wards in­duc­tion on a de­ci­sion tree and us­ing Bayesian lin­ear re­gres­sion to pre­dict pos­te­rior prob­a­bil­ity of each re­main­ing drug’s suc­cess prob­a­bil­ity con­di­tional on pre­vi­ous drugs not work­ing (rather than us­ing just the un­con­di­tion­al, mar­gin­al, prob­a­bil­ity of any cat re­spond­ing to each):


predictBayes <- memoize(function (action, observations, df) {
    formula <- as.formula(paste(action, paste(c(names(observations), "1"), collapse=" + "), sep=" ~ "))
    b <- stan_glm(formula, family=binomial(), algorithm="optimizing", data=bol2017Responses)
    if (length(observations)==0) { mean(inv.logit(predict(b))) } else { inv.logit(predict(b,[1]) } })

f <- memoize(function(observations) {
    allActions <- colnames(bol2017Responses)
    actions <- allActions[!allActions %in% (names(observations))] # untried drugs
    if (length(actions) == 0) { return(0) } else {

       actionCosts <- costs[costs$Drug %in% actions,]$Loss

       probabilities <- c(numeric())
       for (i in 1:length(actions)) {
          probabilities[i] <- predictBayes(actions[i], observations, bol2017Responses)
       lossActions <- c(numeric())

       for (i in 1:length(actions)) {
           # we pay the loss to test each action; if successful, we stop here, otherwise we add a FALSE observation and recurse
           obs <- list(a=FALSE); names(obs) <- actions[i]
           obs <- c(observations, obs)
           newHistory <- obs[order(unlist(obs), decreasing = TRUE)] # sort history to avoid unnecessarily different but equivalent calls
           # 1. incur cost of each drug; success means stopping; failure: augment history with failure observation, and look for an optimal path through remaining actions recursively by calling 'f' again
           lossActions[i] <- actionCosts[i] + probabilities[i]*0 + ((1-probabilities[i]) * (f(newHistory)))
       print(data.frame(Actions=actions, P=probabilities, Loss=lossActions))
       print(paste("Optimal action: ", actions[which.min(lossActions)], "; given observations: ", names(observations), observations))
       return(min(lossActions)) }
# f(list(Catnip=FALSE, Honeysuckle=FALSE, Silvervine=FALSE))

## No data, optimal choice is catnip:
#       Actions            P        Loss
# 1      Catnip 0.6810641502 15.79007271
# 2    Valerian 0.4731509696 16.92706363
# 3  Silvervine 0.7879218896 20.92153367
# 4 Honeysuckle 0.5276423201 16.51408849

## With catnip resistance, optimal choice is honeysuckle:
#       Actions            P        Loss
# 1    Valerian 0.2005122547 23.27730700
# 2  Silvervine 0.7202520977 21.49101933
# 3 Honeysuckle 0.3287608075 21.41519278

## With catnip/honeysuckle resistance, optimal choice is silvervine, and if silvervine doesn't work, only Valerian is left:
#      Actions            P        Loss
# 1   Valerian 0.1695397115 21.75727933
# 2 Silvervine 0.6813415396 20.00060922

## Final optimal policy: catnip, honeysuckle, silvervine, Valerian; aside from catnip, almost reverse of greedy policy.

Known cat stimulants

Fig­ure 1. “A cat on Christ­mas Is­land in an ap­par­ent drug-in­duced stu­por after chew­ing the roots of Aca­lypha in­dica.” (From .)
Fig­ure 7: bob­cat with sil­vervine (From Bol et al 2017.)

“Cat­nip, Va­le­ri­an, Hon­ey­suckle and other cat-at­trac­tant plants”, Hartwell 2008:

  • : ac­tive in­gre­di­ent nepeta­lac­tone

  • Lonicera Tatar­ica (Tatar­ian Hon­ey­suck­le) : nepeta­lac­tone TODO: that can’t be the only in­gre­di­ent if cat­nip does­n’t work on Percy and hon­ey­suckle does?

  • Va­le­ri­an:

    • Va­ler­ian offic­i­nalis : ac­tive in­gre­di­ent ac­tini­dine
    • Va­le­ri­ana celtica : ac­tive in­gre­di­ents nepeta­lac­tone (Bic­chi et al 1983)
  • Ac­tini­dia Polygama (Japan­ese Cat­nip or Matatabi or Sil­vervine or sil­ver vine or cat pow­der) and Ac­tini­dia macros­perma : ac­tive in­gre­di­ent Ac­tini­dine and di­hy­droac­tini­d­i­olide

  • (In­dian acalypha/Indian net­tle), ac­tive in­gre­di­ents: Isodi­hy­dronepeta­lac­tone, Isoiridomyrmecin (eg Scaffidi et al 2016)

  • cat thyme (teu­crium marum) : ac­tive in­gre­di­ent TODO

  • Buck­bean (Menyan­thes tri­fo­li­ata): mit­sug­ashi­walac­tone

  • North­ern ground­cone (Bosch­ni­akia rossi­ca): bosch­ni­akine and bosch­nialac­tone

  • Yel­low­bells (Te­coma stan­s): bosch­ni­akine and ac­tini­dine

  • Trum­pet Creeper (Camp­sis rad­i­can­s): may bosch­ni­akine

  • Guelder Rose (Vibur­num op­u­lus, some­times called Cran­berry Bush and most com­monly found in cul­ti­va­tion as the Snow­ball Tree)

  • the peren­nial Dit­tany of Crete (Ori­g­anum dictamnus/Hop Mar­jo­ram)

  • the spring-flow­er­ing an­nual Baby Blue-eyes (Nemophila men­ziesii)

  • the Zim­bab­wean plant Zinz­iba (Lip­pia ja­van­ica aka Ver­bena ja­van­i­ca).


  • there are anec­do­tal re­ports that some cats are at­tracted to olive prod­ucts: olive wood, olive oil, and olive fruits them­selves

Local cat experiments

The cat­nip lit­er­a­ture has a good sam­ple of what the cat­nip fre­quency re­sponse is, but it’s clear that a lot of cats are im­mune and their own­ers need to use one of the many sub­sti­tutes. The lit­er­a­ture does not seem to have much, if any, cov­er­age of all the main al­ter­na­tives, so own­ers don’t know what to try after cat­nip. There’s also no in­for­ma­tion on any cor­re­la­tions be­tween re­spons­es: does cat­nip im­mu­nity cause sus­cep­ti­bil­ity to a differ­ent stim­u­lant? Are some cats more re­sponse to stim­u­lants in gen­er­al? If we know a cat is im­mune to, say, cat­nip and va­le­ri­an, can we bet­ter pre­dict what a owner should try next?

Since cats are easy to come by and the stim­u­lants are cheap, I thought it might be in­ter­est­ing to as­sem­ble a col­lec­tion of stim­u­lants and sys­tem­at­i­cally try them out on each cat I should hap­pen to meet. Specifi­cal­ly, I’ll look at the most com­mon and easy to come by stim­u­lants, since it’s not use­ful to dis­cover that some ex­tinct African flower is su­per-po­tent:

  • Cat­nip (ob­vi­ous­ly)
  • Tatar­ian hon­ey­suckle (one of the most fre­quently men­tioned al­ter­na­tives)
  • Va­ler­ian (not as com­monly men­tioned, but very cheap due to its pop­u­lar­ity as a herbal sup­ple­ment for sleep & anx­i­ety)
  • Sil­vervine (rarer & more ex­pen­sive but still ac­ces­si­ble, and re­put­edly quite effec­tive)
  • Cat thyme
  • Olive oil/wood (cats’ re­act­ing to olive-re­lated things is an ob­scure & anec­do­tal claim; but both are easy to get and in­cluded for the sake of com­pre­hen­sive­ness)


For each stim­u­lant, one clean nev­er-used feather was put into a clean jar along with a good help­ing of the rel­e­vant stim­u­lant, and shaken and left to sit. The olive wood would not fit into a jar, so I sawed it in half, saved the saw­dust, and put the two wood blocks, saw­dust, and feather into a lit­tle zi­plock bag. The wand lets the feath­ers be added or re­moved eas­ily so I can test each feather one at a time by switch­ing feath­ers, play­ing with the cat for 5 min­utes, and wait­ing for any re­sponse or in­di­ca­tion of in­ter­est be­yond reg­u­lar chase. This works well, aside from the sil­vervine pow­der where in­evitably some of the pow­der falls off or blows out of the con­tain­er, so it’s best to do the sil­vervine last.


Cat Sex Age Fixed Color Kind Cat­nip Va­ler­ian Hon­ey­suckle Sil­vervine Olive wood Olive oil
My cat M 1.5 1 black Do­mes­tic long 0 1 0 1 0 0
Percy M 3 1 brown Tabby 0 0 1 1 0 0
Kiki M 2 1 grey Tabby 1
Stormy M 10 1 grey Russ­ian Blue
Sara F 10 1 brown Tabby 1
Whitey F 5 1 white Do­mes­tic short 1
Sassy F 12 1 or­ange Do­mes­tic short 0 0 0 1 0 0

De­scrip­tion of effects:

  • Cat­nip: too well known to need much de­scrip­tion. Cat­nip re­spon­der cats be­come ‘hy­per’, un­in­hib­it­ed, play­ful, in­ter­ested in the cat­nip toy.

    Test­ing it in my 2 non-re­spon­der cats in De­cem­ber 2014, Percy and my cat ini­tially sniffed it for a few sec­onds and then ig­nored it after­wards, re­gard­less of whether I shook a quar­ter kilo­gram of cat­nip leaf un­der their nose or let the open jar sit next to them. Like­wise, at­tempts to in­ter­est them in the cat­nip ex­tract spray in No­vem­ber 2015 also failed. In Oc­to­ber 2016, I pur­chased ~100g of dried cat­nip leaves at a lo­cal Re­nais­sance fes­ti­val to have a backup for the cat­nip ex­tract spray and per­haps try out “cat­nip tea” my­self (and if I can’t find any use for it, I can al­ways ex­per­i­ment with home steam dis­til­la­tion of cat­nip oil from cat­nip leaves!). Retest­ing Percy/my cat with the new leaves, Percy re­mained un­in­ter­ested but this time my cat was in­ter­ested in the plas­tic bag con­tain­ing the cat­nip leaves, try­ing to claw and chew it, so I put ~10g into a lit­tle cot­ton bag and give it to him, which he be­gan to chew and claw and even laid down to hold it in his paws and kick at it - how­ev­er, de­spite re­sem­bling the cat­nip re­spon­se, he was not hy­per, and he did not re­peat the re­ac­tion on 4 sub­se­quent oc­ca­sions I tried to in­ter­est him in the cat­nip bag (spray­ing it with the cat­nip ex­tract did not help). This makes me won­der if cat­nip re­sponse might have some ul­tra­-long tol­er­ance like some drugs in hu­mans which take weeks or months for tol­er­ance to be re­stored, or if the cat­nip re­sponse is not bi­modal after all (cat­nip be­ing an dom­i­nant gene would cer­tainly seem like it al­most has to pro­duce a bimodal/binary trait, but we have only Todd 1962 as ev­i­dence for it be­ing dom­i­nant, and he used a sin­gle small breed­ing colony and no one has ever fol­lowed up & tried to repli­cate it that I know of). Per­haps the is­sue of mea­sure­ment er­ror has been un­der­es­ti­mated in past stud­ies and many cats will only dis­play a cat­nip re­sponse oc­ca­sion­ally or un­der ideal con­di­tions, and so the es­ti­mates of cat­nip im­mu­nity are heav­ily bi­ased up­wards?

  • Va­le­ri­an: on my cat, pro­duces an in­ter­est­ing mix of pas­sive­ness and pos­ses­sive­ness - after on­set and a long , he mostly lays on the floor pas­sive­ly, oc­ca­sion­ally pulling him­self across it to­wards the toy, but gen­er­ally mak­ing lit­tle effort to hunt; if the toy comes within reach, though, then he seizes it en­er­get­i­cally and abruptly be­gins clasp­ing it to his face, chew­ing it, curl­ing up around it and kick­ing at the toy with his hind legs. Even­tu­ally he can be coaxed into play­ing chase nor­mal­ly, with his usual level of com­pe­tence and in­ter­est. Ac­tively re­pelled Sassy.

  • Hon­ey­suck­le: on Per­cy, had a gen­eral stim­u­lant effect; de­spite be­ing fat, lazy, and usu­ally en­tirely un­in­ter­ested in chase, he will make an effort to play after sniffing a hon­ey­suck­le-im­preg­nated toy. This stim­u­lat­ing effect does not pro­duce the un-in­hi­bi­tion of cat­nip, and seems fairly mild. Ac­tively re­pelled Sassy.

  • Sil­vervine:

    1. on my cat, a gen­eral stim­u­lat­ing effect with con­sid­er­able in­ter­est in play­ing chase or watch­ing the toy, but cu­ri­ous­ly, he makes many fewer at­tempts at at­tack­ing or chas­ing and when he does, he is dis­tinctly slower (and thus, less effec­tive) than usu­al. His co­or­di­na­tion is fine - he’s not clumsy or falling over - but he’s just not as effec­tive (in a way hard to pin down specifi­cal­ly).
    2. On Per­cy, like­wise a gen­eral stim­u­lat­ing effect but far more effec­tive than the hon­ey­suckle in in­duc­ing chase play, with him even try­ing out jumps when coaxed ap­pro­pri­ate­ly; he may be less effec­tive, like my cat when affect­ed, but he plays chase so lit­tle that it’s im­pos­si­ble for me to make any com­par­isons with his ‘nor­mal’ chase be­hav­ior.
    3. Sassy: sim­i­lar. More time on back while play­ing chase than usu­al.
  • Olive oil/wood: all cats showed brief in­ter­est in smell, then ig­nored en­tire­ly.


Breeding cats to increase frequency of catnip response

I sketch out a thresh­old se­lec­tion breed­ing pro­gram for in­creas­ing cat­nip re­sponse fre­quen­cy. Based on Vil­lani 2011’s mea­sured her­i­tabil­i­ties of cat­nip re­sponse (cor­rected for mea­sure­ment er­ror), se­lect­ing ex­clu­sively re­spon­ders would re­sult in cat­nip re­sponse be­com­ing nearly uni­ver­sal (~95%) within ~7 gen­er­a­tions or po­ten­tially less than a decade.

Given the ben­e­fits of cat­nip for be­hav­ioral en­rich­ment, it’s un­for­tu­nate that cat breed­ers have not used a lit­tle se­lec­tion pres­sure to make cat­nip re­sponse uni­ver­sal. There are 3 ma­jor sce­nar­ios for cat­nip breed­ing:

  1. Mendelian au­to­so­mal dom­i­nant: mark­er-as­sisted ge­netic se­lec­tion: 1 gen­er­a­tion to fix­a­tion

    A ge­netic test for cat­nip re­sponse is not avail­able as of July 2017, since the al­lele has not even been lo­cal­ized to any chro­mo­somes, much less iden­ti­fied, and given the small niche of cat ge­net­ics re­search, large-s­cale GWAS would al­most cer­tainly be very ex­pen­sive (eg the 99 Lives Cat Genome Se­quenc­ing Ini­tia­tive re­quires, as of July 2017, ~$7000 to se­quence 1 cat genome, which is >7x more than it would cost to se­quence a hu­man genome via Ver­i­tas, and they have se­quenced 53 cats, in­creas­ing to 131 by Feb­ru­ary 2019 as their 30x WGS cost has ap­par­ently dropped to ~$1500; to se­quence “”, tar­geted $6500 in May 2015). As cat­nip re­sponse ap­pears some­what sim­i­lar across the fe­lids, a suc­cess­ful find of a cat­nip gene in an­other species might make it much eas­ier to find it in cats, re­duc­ing the sam­ple size re­quire­ment.

    For­tu­nate­ly, cats are oth­er­wise not ex­pen­sive to test, as a num­ber of suc­cess­ful ex­ist­ing fe­line sali­va-based ge­netic tests in­di­cate (Lyons 2009, , ): as of Au­gust 2017, the UC Davis Vet­eri­nary Ge­net­ics Lab­o­ra­tory offers coat col­or, an­ces­try, parent­age, blood group, ge­netic dis­eases (Pro­gres­sive Reti­nal Atrophy/PRA-PK De­fi­cien­cy, Glyco­gen Stor­age Dis­ease Type IV, GM1 & GM2 Ko­rat Gan­gliosi­do­sis, Poly­cys­tic Kid­ney Dis­ease etc) for prices rang­ing $40-$120; the UK Lang­ford Vets (U­ni­ver­sity of Bris­tol) offers a sim­i­lar list of tests start­ing at £36.60/$48; the US ’s offers a more lim­ited se­lec­tion but again all for $45. The Mor­ris An­i­mal Foun­da­tion spon­sored de­vel­op­ment of an Il­lu­mina fe­line SNP ar­ray (the “Il­lu­mina In­finium iS­e­lect 63K Cat DNA Ar­ray”) start­ing around 2011 (with un­for­tu­nately a lim­ited se­lec­tion of only 70k SNPs as op­posed to the 500k+ stan­dard in hu­man SNP ar­rays), and as of 2014, was offer­ing it for$100 to re­searchers. Hence, it is plau­si­ble that after dis­cov­er­ing the cat­nip al­lele, the cost of test­ing a sin­gle cat might be <$50.

    Once a ge­netic test does be­come avail­able at suffi­ciently low cost, it offers by far the fastest and most pow­er­ful se­lec­tion method. Given a ge­netic test for the cat­nip al­lele (as a com­mon vari­ant, it is likely eas­ily tested for), breed­ing could be con­ducted in 1 gen­er­a­tion: test the pop­u­la­tion of cat­nip re­spon­ders, and breed only the ho­mozy­gous dom­i­nant cats (ie the cats with 2 copies), who make will make up ~ of the pop­u­la­tion. All off­spring will then also be ho­mozy­gous dom­i­nant & thus cat­nip re­spon­ders, and cat­nip re­sponse rates will be 100% bar­ring any fur­ther in­tro­duc­tion from out­side the breed­ing pop­u­la­tion of re­ces­sive car­ri­ers. This sort of sin­gle-gen­er­a­tion se­lec­tion would be doable at fairly mod­est to­tal cost, <$100k (eg start with 1000 cats, test for cat­nip re­spon­se; about half will re­spond, and test­ing each at $50 would cost ~$25k, of which about half will be ho­mozy­gous rather than het­erozy­gous, giv­ing a large found­ing pop­u­la­tion of ~250 cats all of whose de­scen­dants will be cat­nip re­spon­der­s).

  2. Mendelian au­to­so­mal dom­i­nant: phe­no­typic se­lec­tion: ~9 gen­er­a­tions to near-u­ni­ver­sal­ity (>=99%)

    As­sum­ing there is no ge­netic test, one can in­stead breed based on the ob­served phe­no­type of cat­nip re­spon­se; this will be slower and less effi­cient be­cause het­erozy­gous and ho­mozy­gous can­not be dis­tin­guished.

    But if Todd is cor­rect about the al­lele be­ing dom­i­nant, cat­nip re­sponse is still eas­ily bred, since se­lec­tion against a re­ces­sive pro­ceeds fast when start­ing from a high fre­quen­cy. Un­der the Mendelian au­to­so­mal dom­i­nant the­o­ry, if the cat­nip re­ces­sive is present at per Todd 1962, and we would like to de­crease the rate of cat­nip re­sis­tance in a breed to <=1%, then we need to de­crease the fre­quency to . If we breed only cat­nip re­spon­ders (which for­tu­nately are the ma­jor­ity al­ready), this cor­re­sponds to a s=1, and the num­ber of gen­er­a­tions has the sim­ple equa­tion (more gen­eral treat­ments: 1, 2) or gen­er­a­tions. Cats ma­ture re­pro­duc­tively at 18 months & preg­nancy is around 2 months, so 8.2 gen­er­a­tions would take ~14 years (). So a phe­no­typic cat­nip breed­ing pro­gram need not take an in­fea­si­ble amount of time based on Todd 1962’s es­ti­mates.

  3. poly­genic li­a­bil­i­ty-thresh­old: phe­no­typic se­lec­tion: ~25 gen­er­a­tions to near-u­ni­ver­sal­ity

    Al­ter­na­tive­ly, if Todd is in­cor­rect about cat­nip be­ing Mendelian dom­i­nant con­trolled trait, it still ap­pears to run in fam­i­lies & species and thus have a ge­netic ba­sis, so, since the trait ap­pears bi­na­ry, the true ge­netic ar­chi­tec­ture might then be a trait. Phe­no­typic se­lec­tion in the li­a­bil­ity thresh­old trait de­pends on the pop­u­la­tion fre­quency of the trait (which de­fines the un­ob­served la­tent thresh­old’s start­ing point, and effi­cacy slows at the ex­tremes of 0 and 1) and on the her­i­tabil­ity of the trait (which de­fines the ge­netic re­sponse to each gen­er­a­tion of se­lec­tion; un­for­tu­nate­ly, un­known for cat­s). Large-s­cale hu­man twin stud­ies such as Pol­d­er­man et al 2015 turn in a grand mean across all stud­ied hu­man traits of ~50% her­i­tabil­i­ty, and the largest mul­ti­-be­hav­ioral-trait cat her­i­tabil­ity study I know of, , like­wise ob­tains tight es­ti­mates of 50–50% her­i­tabil­i­ty, so a pri­ori one would ex­pect a rea­son­ably high her­i­tabil­i­ty, and Vil­lani 2011’s large cat­nip re­sults in­di­cate, con­sid­er­ing the mea­sure­ment er­ror, a her­i­tabil­ity of at least 0.7, so we will con­sider that sce­nar­io:

    threshold_select <- function(fraction_0, heritability) {
        fraction_probit_0 = qnorm(fraction_0)
        ## threshold for not manifesting schizophrenia:
        s_0 = dnorm(fraction_probit_0) / fraction_0
        ## new rate of schizophrenia after one selection where 100% of schizophrenics never reproduce:
        fraction_probit_1 = fraction_probit_0 + heritability * s_0
        fraction_1 = pnorm(fraction_probit_1)
        ## how much did we reduce schizophrenia in percentage terms?
        print(paste0("Start: population fraction: ", fraction_0, "; liability threshold: ", fraction_probit_0, "; Selection intensity: ", s_0))
        print(paste0("End: liability threshold: ", fraction_probit_1, "; population fraction: ", fraction_1, "; Total population reduction: ",
            fraction_0 - fraction_1, "; Percentage reduction: ", (1-((1-fraction_1) / (1-fraction_0)))*100))
    heritability <- 0.70; frac <- 0.61
    threshold_select(frac, heritability)
    # ...
    # [1] 0.7641164429
    generations <- 0;
    while (frac < 0.99) { frac <- threshold_select(frac, heritability); generations <- generations+1 }
    # ...
    # [1] 25

    Pro­gress, while ini­tially swift (eg get­ting to 95% only takes ~7 gen­er­a­tions), slows down rapidly to­wards the tar­get of 99% re­sponse rates. The se­lec­tion, es­pe­cially to­wards the end, could be im­proved by tak­ing into ac­count ge­netic in­for­ma­tion such as pedi­gree or GWAS-based poly­genic scores in or­der to se­lect against cats with a high li­a­bil­ity for cat­nip re­sis­tance but who do not dis­play the phe­no­type; mod­el­ing that, how­ev­er, would be diffi­cult with­out more da­ta.

  1. For ex­am­ple, Todd 1962’s ge­netic analy­sis was based on just 34 cats of which 7 cats’ re­sponse were un­known; as far as I can tell, an­other pedi­gree analy­sis has never been done since then, much less ex­tended to newer ge­netic meth­ods like or GWASes, al­though it con­tin­ues to be cited as the jus­ti­fi­ca­tion for treat­ing cat­nip re­sponse as an au­to­so­mal dom­i­nant ge­netic trait.↩︎

  2. An ex­am­ple of founder effects in cat pop­u­la­tions are the feral cats of , whose fur col­ors are >95% black (or black with white spot­s): Dreux 1970, Todd 1971, Dreux 1974, Pas­cal 1994, Pon­tier et al 2004 ↩︎

  3. If cat­nip sen­si­tiv­ity fre­quency was 70% in 1950, and for the sake of ar­gu­ment we ac­cepted that the pro­por­tion had de­creased ~0.0024 per year and was 54.16% in 2016, and we also ac­cept Todd 1962’s analy­sis that cat­nip sen­si­tiv­ity is a dom­i­nant gene, then that im­plies that the fre­quency of the gene in 1950 was and so in 1950 p = 0.45; sim­i­lar­ly, , and so in 2016 p = 0.30, so the gene fre­quency would’ve fallen by 0.15 from 1950 to 2016. If a do­mes­tic or wild cat gen­er­a­tion is 3 years, then that 66 years is >22 cat gen­er­a­tions, and di­vid­ing a to­tal fall of 15% over that pe­ri­od, the gene fre­quency would be falling ~0.68% per gen­er­a­tion.

    While this could be caused by fairly weak se­lec­tion against cat­nip re­spon­ders, it’s hard to imag­ine what could cause that se­lec­tion or how it is con­sis­tent with the con­tin­ued ex­is­tence of cat­nip re­spon­ders given that: cat­nip has no known ill effects on cats, is rarely found in the wild, most cats are never ex­posed, those cats which are ex­posed at all tend to be pets which are spayed/neutered, no solid sex or breed cor­re­la­tion has been ob­served, and the ex­is­tence of cat­nip re­spon­ders has been doc­u­mented for cen­turies (ac­cord­ing to Tucker & Tucker 1988, , died 1705, was the first, and Gary Lock­hart at­trib­utes the first men­tion of cats/catnip to , died 1048).↩︎