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 small , 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, “Inheritance of the catnip response in domestic cats” 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 Hardy-Weinberg: p2+2pq; p2+2pq=0.69;q2=0.31, then p=0.44;q=0.56) 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: 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 Hyenas (Hyenidae): 0⁄3 responders of 2 males/1 female (pg41/72), unspecified age, genus, or species, presumably either spotted or striped hyenas. 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 “ligeress” (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 isomers; 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.

[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 Civettictis and Crossarchus [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.

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.

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 Japanese Bobtail) after their introduction ~500AD from Korea, may have much higher population frequencies or even fixed the catnip mutation due to genetic drift or a founder effect ; 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 L-alanine 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 black-footed cats (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.

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 margay 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 Australian wildcats (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 stone marten & 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 camera traps.

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 2238=0.58 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, “Responsiveness of cats (Felidae) to silver vine (Actinidia polygama), Tatarian honeysuckle (Lonicera tatarica), valerian (Valeriana officinalis) and catnip (Nepeta cataria)”: 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.