Zoologist, media consultant, and science writer, Dr Karl Shuker is also one of the best known cryptozoologists in the world. He is the author of such seminal works as Mystery Cats of the World (1989), The Lost Ark: New and Rediscovered Animals of the 20th Century (1993; greatly expanded in 2012 as The Encyclopaedia of New and Rediscovered Animals), Dragons: A Natural History (1995), In Search of Prehistoric Survivors (1995), The Unexplained (1996), From Flying Toads To Snakes With Wings (1997), Mysteries of Planet Earth (1999), The Hidden Powers of Animals (2001), The Beasts That Hide From Man (2003), Extraordinary Animals Revisited (2007), Dr Shuker's Casebook (2008), Karl Shuker's Alien Zoo: From the Pages of Fortean Times (2010), Cats of Magic, Mythology, and Mystery (2012), Mirabilis: A Carnival of Cryptozoology and Unnatural History (2013), Dragons in Zoology, Cryptozoology, and Culture (2013), The Menagerie of Marvels (2014), A Manifestation of Monsters (2015), Here's Nessie! (2016), and what is widely considered to be his cryptozoological magnum opus, Still In Search Of Prehistoric Survivors (2016) - plus, very excitingly, his first two long-awaited, much-requested ShukerNature blog books (2019, 2020).

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Saturday 2 September 2017


The Rodriguez onza (© International Society of Cryptozoology – permission to reproduce in my writings granted to me in perpetuity by J. Richard Greenwell, ISC Secretary)

For zoologists, the year 1986 opened in a decidedly dramatic manner - with the apparent procurement on 1 January of a legendary creature whose existence had been denied by science for centuries. That evening, Mexican ranger Andres Rodriguez Murillo surprised a very large cat close to his home in the valley behind Parrot Mountain, in Mexico's Sinaloa State. Fearing that it was a jaguar about to attack him, he shot it, but when he examined its body he found that it was neither a jaguar Panthera onca nor a puma Puma concolor - the only other large felid 'officially' existing in Mexico.

It did resemble a puma superficially, but its limbs were longer and its body was more slender, giving it a cheetah-like outline; in addition, its ears were unusually big, and the inner surfaces of its forelimbs bore dark markings not possessed by pumas. As Rodriguez had little knowledge of wildlife, he contacted an expert hunter by the name of Manuel Vega to come over and identify it for him. When Vega arrived, he felt sure that he recognised the cat - identifying it as an onza, the fabled third large cat of Mexico.

The puma (top) and the jaguar (bottom) – Mexico's two official large cats (public domain)

The onza's existence within the rugged mountainlands of the Sierra Madre Occidental is supported by more than 300 years' worth of local eyewitness accounts (even including the testimony of visiting missionaries and Jesuit priests) from Sinaloa and also Sonora. Yet these had always been dismissed by zoologists as reports of poorly-seen or misidentified pumas.

Conversely, back in the 18th Century accounts of this controversial creature appeared in the works of several of Mexico's learned Jesuit scholar-priests. They recorded that the onza is greatly feared by ranchers and peasants, and is said to be an unusually aggressive animal, far more dangerous than either the burly jaguar or the diffident puma, but far more elusive too.

My very first book, Mystery Cats of the World (1989) (© Dr Karl Shuker)

However, it may be that the onza's history can be traced back even further than this. According to Spanish conquistador Bernal Diaz del Castillo, in 1519 the famous zoo owned by the Aztec king Montezuma contained two types of 'lion' (puma). One was the normal puma, but the other was a much more mystifying cat that supposedly resembled a wolf. As wolves have noticeably longer legs than pumas, was this unidentified animal the onza? Further details concerning the onza's early history are given in my book Mystery Cats of the World.

Some 20th-century accounts of alleged onzas had actually been supported for a short time by complete specimens, though in every case these were somehow lost or destroyed. In spring 1926, for example, hunter-cowboy C.B. Ruggles trapped and killed a supposed onza southeast of Yaqui River in Mexico's Sonora State. After taking some photos of its carcase, and noting that it had very skinny hindquarters, with dark spots on the inner side of its limbs, Ruggles discarded it. A few years later, American naturalist J. Frank Dobie reported shooting an onza caught in traps set on Mexico's Barrancas de la Viboras; regrettably, its skin was subsequently devoured by bugs.

Clell and Dale Lee posing with their hunting dogs alongside the carcase of the Shirk onza (© International Society of Cryptozoology – permission to reproduce in my writings granted to me in perpetuity by J. Richard Greenwell, ISC Secretary)

In 1938, while in the company of renowned hunters Dale and Clell Lee from Arizona, Indiana banker Joseph Shirk shot an onza on Sinaloa's La Silla Mountain; photos show that, as with all of the others, it resembled an extremely gracile, long-limbed puma with big ears and unusual limb markings. Although much of its carcase was discarded, its skull was retained - only to vanish without trace when sent to a museum whose name, frustratingly, does not appear to have been placed on record. The dead body of a large unidentified felid that may well have been an onza was taken to Texas University in the late 1950s, but this cannot be traced either.

J. Richard Greenwell, at that time the secretary of the International Society of Cryptozoology (ISC), who had a particular interest in the onza, succeeded in locating two onza skulls - one from a specimen shot in 1938 on La Silla Mountain by R.R.M. Carpenter while accompanied by Dale and Clell Lee (thus providing a remarkable parallel to the history of the Shirk specimen), the other from an onza shot by Jesus Vega (father of Manuel Vega) in much the same area sometime during the mid-1970s (this skull is now owned by rancher Ricardo Urquijo).

Robert E. Marshall and Ricardo Urquijo with the Vega onza skull (© International Society of Cryptozoology – permission to reproduce in my writings granted to me in perpetuity by J. Richard Greenwell, ISC Secretary)

Additionally, another onza investigator, Arizona hunter Robert E. Marshall, was successful in obtaining the incomplete skull (its lower jaw was missing) of an onza shot during the 1950s at Los Frailes, Sinaloa. Marshall was also the author of The Onza – published in 1961, it was the first book devoted to this cryptid; a second, Onza! The Hunt For a Legendary Cat, written by Neil B. Carmony, was published in 1995. Both make fascinating reading, and I highly recommend them to anyone interested in cryptozoology.

Around the time of the shooting of the Rodriguez specimen in January 1986, an onza was allegedly captured alive, and held for several days in captivity at a ranch in northern Sonora, where it was supposedly photographed too. Tragically, however, when no-one showed any interest in it, its owner shot it and threw its body away. As for the photographs, these have yet to make a published appearance. And in early 1987, yet another onza was reportedly shot in Sinaloa, this time by a wealthy Mazatlan businessman; but, true to form, its remains were not preserved.

Robert E. Marshall's book The Onza (© Robert E. Marshall/Exposition Press – reproduced here on a strictly educational, non-commercial Fair Use basis only)

In short, with the exception of three skulls, physical remains of onzas have displayed a disconcerting tendency to disappear beyond the reach of scientists. The Rodriguez specimen, however, changed all of that - for instead of destroying its remains, the ranchers contacted Richard Greenwell. Following a complex series of interchanges, the precious specimen was transported to the Regional Diagnostic Laboratory of Animal Pathology, belonging to Mexico's Ministry of Agriculture and sited in Mazatlan, Sinaloa.

There it was painstakingly studied and dissected by a biological team headed by American puma researcher Dr Troy Best, who had been working alongside Greenwell during his earlier onza investigations. After the dissection, extensive samples of skeletal material, tissues, and blood were taken for examination and analysis in various U.S. research institutions, in a bid to uncover the onza's taxonomic status. Several different taxonomic identities have been offered over the years, but the principal four are as follows.

Neil B. Carmony's book Onza! (© Neil B. Carmony/High-Lonesome Books – reproduced here on a strictly educational, non-commercial Fair Use basis only)

The most exciting possibility is that it could be a currently undescribed species - one that quite conceivably descended from the typical puma, but later diverged from it to fill the ecological niche left vacant by the extinction approximately 11,000 years ago of Miracinonyx trumani - an extraordinary felid now known to have been a true American cheetah (it was first classed as a cheetah-like puma). Indeed, German felid specialist Dr Helmut Hemmer initially mooted that the onza may actually be a surviving representative of Truman's cheetah, but after studying casts of two onza skulls and comparing them with fossil material from M. trumani, he changed his mind. However, regardless of whether it is even related to (let alone synonymous with) Truman's cheetah, if the onza is indeed a valid species in its own right it should be distinguishable from the puma via the biochemical and genetic analyses conducted by those researchers studying the Rodriguez specimen (see below).

Another intriguing, frequently-raised possibility is that the onza is a naturally-occurring hybrid of puma and jaguar (i.e. either a pumajag or a jaguma). No evidence for this identity was obtained, however, from examination of the Rodriguez specimen. In any case, hybrids of this type that have been bred in captivity bear no resemblance to onzas, appearing visibly intermediate between puma and jaguar instead.

Artistic representation of a Truman's cheetah attacking a pronghorn (© Hodari Nundu)

Two rather more conservative but still-interesting identities remain. The onza may simply be a mutant, non-taxonomically distinct form of the puma, the result of a genetic aberration that has yielded an uncommonly slim, leggy variety. If so, could it even be that an atavistic phenotype-influencing gene surviving from the period of shared ancestry by pumas and cheetahs but suppressed in normal pumas is somehow expressing itself in onza specimens, i.e. is responsible for 'onzaism' in pumas? If we take the Rodriguez specimen as a bona fide onza, the onza's gracility is, indisputably, a natural facet of its appearance (rather than starvation-induced emaciation), because this specimen was found to possess adequate amounts of body fat. Genetically-induced onzaism may be confined to Mexico due to genetic drift; then again, as I noted in my 1989 mystery cats book, onza-like cats have also been reported from South America, so if the onza is indeed a freak non-taxonomic variety of puma, perhaps the mutant onza-inducing gene (should it exist) is more widely distributed among the global puma population after all. If not a genetic freak, the onza could be a separate subspecies of puma, kept apart from the Mexican puma Puma concolor azteca by behavioural differences and dissimilar habitat preferences. If the last-mentioned identity were the correct one, however, then once again (as with the possibility that it is a separate species) we would expect the onza to be distinguishable biochemically and genetically from other pumas. But is it?

Early biochemical tests had failed to uncover any characteristics differentiating the Rodriguez specimen from pumas, which would seem to suggest that onza and puma are very closely related. Yet this conclusion stems from a fundamental assumption that, although widely accepted in the zoological (and especially the cryptozoological) community, has never actually been confirmed. Namely, that the onza specimen whose tissues provided these biochemical results, i.e. the Rodriguez specimen, really was an onza!

Illustration of a pair of pumas (© William M. Rebsamen)

However, is it conceivable that Manuel Vega had been mistaken, and that this animal had merely been a malformed or infirm puma that only outwardly resembled a genuine onza? After reflecting upon this disturbing possibility for some time, in January 1998 I heretically aired it within an onza article of mine published in the British monthly magazine All About Cats – and it seems that my suspicions may indeed have been justified.

Only a few months after my article had appeared in print, the much-delayed volume of the ISC's scientific journal Cryptozoology covering the years 1993-1996 was finally published, and contained a report by a research team featuring Prof. Stephen O'Brien, an expert in feline molecular genetics. The team's report revealed that after conducting comparative protein and mitochondrial DNA analyses using tissue samples taken from the Rodriguez onza and from specimens of known North American cat species, the results obtained for the Rodriguez onza were found to be indistinguishable from those of North American pumas. Of course, this does not necessarily mean that all onzas are pumas, but how savagely ironic it would be for the most celebrated supposed onza specimen not to have been an onza after all.

Cutting from the Arizona Daily Star (Tucson) newspaper dated 1 October 1938, featuring the then newly-snapped photograph of Clell and Dale Lee with the Shirk onza - the first onza photo ever published in the USA (© International Society of Cryptozoology – permission to reproduce in my writings granted to me in perpetuity by J. Richard Greenwell, ISC Secretary)

On 15 April 1995, an alleged male onza was shot behind Parrot Mountain, this time by rancher Raul Jiminez Dominguez. Later that same day, after having been frozen, the onza's corpse was examined by two biologists from the Universidad Nacional Autonoma de Mexico, who took tissue samples away with them for electrophoretic analysis. The remainder of its carcase was preserved and dissected at Mazatlan for future study. Frustratingly, no further information has been made public concerning this specimen, but let us continue to hope that it will eventually provide a precise, unequivocal answer to the longstanding question of the onza's taxonomic identity.

Meanwhile, Mexico's feline enigma seems destined to remain a cryptozoological controversy - a far cry indeed from its popular yet sadly premature image as an erstwhile mystery cat whose reality is no longer in doubt.

Drawing of the onza (© Hodari Nundu)

Finally: please be aware that certain early 20th-Century animal encyclopaedias contain photographs of jaguarundis Puma yagouaroundi labelled as onzas (confusingly, this species is indeed sometimes termed an onza in certain Mexican states, including Jalisco). Nevertheless, anything less like the very large, long-limbed onza of cryptozoology than the much smaller, short-limbed jaguarundi of mainstream zoology would be difficult to imagine.

Having said that: in 2016, Mexican Facebook friend and artist Hodari Nundu revealed that he once saw in Jalisco a dead specimen of what he refers to as a 'giant' jaguarundi. And he subsequently learnt of a possible second location for such specimens, but he has refrained from publicly identifying this location in order to keep these cats safe if any do indeed exist there, noting only that it is a very long distance from Jalisco. This indicates that if other extra-large jaguarundis do occur in Mexico, they may be relatively widespread. Moreover, if they are of this species' dark-grey/black colour phase, such cats may even explain reports here of mystery 'black panthers'.

Jaguarundi, grey colour phase (© Bodlina/Wikipedia – CC BY 3.0 licence)

This ShukerNature blog article is adapted from my book The Encyclopaedia of New and Rediscovered Animals – the most comprehensive book ever published on the subject of such creatures.


  1. What, if anything, did comparison of the onza skulls reveal?

    1. The comparisons were made between onza skulls and fossil M. trumani skulls by Dr Helmut Hemmer, which revealed conclusively that the former mystery cat was not one and the same as the latter fossil cat. I'm not aware of any publicly-released comparisons between onza skulls and puma skulls, though I have read claims that the onza has a shorter face than the puma, but whether if true this difference is statistically significant I cannot say.

    2. Hi!I been hearing about the onza since I was kid my family comes from jalisco.my grandpa n older family members would tell about the onza.they said it lives in the dense mountains of jalisco .that it resembles a long skinny puma with claws like a dog not cat that it jumps really high and imitates the sound of a mule.my uncle told me that one day they were out hunting and he encountered one and shot it.this was around the 80s .they also talk about leoncillo.its a small lion with a small mane .I showed him a picture of an asiatic lion and said that's exactly how they look.any way just thought I'd shared that info with you.

    3. Thanks very much for this interesting info, especially the details re the leoncillo, which is a mystery cat that I'd never previously heard of.

  2. "Miracinonyx trumani - an extraordinary felid now known to have been a true American cheetah (it was first classed as a cheetah-like puma)"

    It is actually the other way around. Miracinonyx was originally classified as a true cheetah, but is now known to have been closer to the puma, just with a cheetah-convergent bauplan.


    Barnett, R. et al. (2005) Evolution of the extinct sabretooths and the American cheetah-like cat. Current Biology, 15(15), 589-590.

    Faurby, S. et al. (2016). The difference between trivial and scientific names: There were never any true cheetahs in North America. Genome Biology, 17, 89.

    1. Hi Tyler, Thanks for the above info. Yes, I was aware of this, but as accurately summarised on the Wikipedia page for M. trumani, the current situation re its taxonomy and evolutionary origin is not as clear-cut as you present above, because: "O'Brien et al. (2016) posit that the supposed homoplasy between the genera is controversial, as it is asserted that [there] is not necessarily any conclusive anatomical or genetic basis for dismissing a homologous relationship between Acinonyx and Miracinonyx". O’Brien, Stephen J.; Koepfli, Klaus Peter; Eizirik, Eduardo; Johnson, Warren; Driscoll, Carlos; Antunes, Agostinho; Schmidt-Kuntzel, Anne; Marker, Laurie; Dobrynin, Pavel (2016-01-01). "Response to Comment by Faurby, Werdelin and Svenning". Genome Biology. 17: 90.

  3. O'Brien et al. do not give any evidence to support a relationship between Miracinonyx and the cheetah.

    1. O'Brien et al. state the following: "Further, when Barnet et al. performed a jack-knife analyses, excluding H. jaguarundi from the phylogenic analysis (H. jaguarundi is a sister taxon to Puma concolor [6, 7, 8]), statistical support for the sister relationship of Puma-Miracinonyx actually increased, an indication that molecular homoplasy was operative in their results [14]. Their conclusion that American cheetah Miracinonyx is not within the African-Asian Acinonyx group is tentative at best and has not been confirmed convincingly." So what they have actually said is that there is no convincing confirmation (i.e. evidence) that Miracinonyx and the cheetah (Acinonyx) are NOT related.

  4. Yes, but they also give nothing to show that they are related. At this point the relationships are unsure.

    1. Precisely, which is why I've stayed with the original notion, as it has yet to be convincingly disproved. Also, once Hemmer had shown that the onza was not a living representative of M. trumani, the issue of whether the latter species was or was not a cheetah became irrelevant to the onza case anyway, so it didn't warrant more than just a passing mention here, hence that is all that I've given it.

    2. If I were to write an account devoted specifically to M. trumani, then obviously I would document in detail all of the controversies concerning its taxonomic affinities, but such a treatment is not warranted in an account focusing upon the onza, so I haven't done so.

  5. If the specimen shot by Rodriguez really was an onza, and if the onza is basically just a funny-looking puma, I would like to suggest a theory about its origins. Some scientists now believe that the puma died out in North America in the Pleistocene-Holocene mass extinction and recolonised the continent from South America some time in the Holocene epoch. The evidence for this is that pumas are much more genetically diverse in South America than in North America. Perhaps a relict population of the original North American puma survived in Mexico and evolved into the onza before the recolonisation. Something similar seems to have happened in the Congo with the Bili ape, which is now believed to be a kind of chimpanzee. It has evolved its large size and its gorilla-like appearance and behaviour because of its isolation from other chimpanzee populations.

  6. Yeah, that’s a slender puma.