Onza

The dog was gone before sunrise, and the prints left in the dirt around the cold fire measured five inches across. C. B. Ruggles and his two companions had ridden into the mountains of eastern Sonora in 1926 to look for a lost mine, and something had come through their camp in the dark making a noise none of them could put a name to. They found what was left of the airedale a short way off, set their traps beside it, and by the following morning had a long dark cat with a heavy head thrashing in the iron. Men from the nearby ranchos came out to look at the carcass. They called it an onza.

Ask a hunter in the Sierra Madre Occidental today how many big cats live in the sierra and the answer comes back the way it has for two hundred years: three. There is the tigre, which is the jaguar. There is the león, which is the mountain lion. And there is the onza, which is like a león but lighter in build, longer in the leg, and very much less inclined to run.

That third cat has been in the written record since before Mexico was Mexico. Ignaz Pfefferkorn, a Jesuit who spent eleven years in the Sonoran missions until the Spanish crown expelled his order in 1767, wrote up the province from exile in Germany and published it at Cologne in 1794. He gives all three cats in careful detail. Of the onza he says it is a little thinner and paler than the puma and a great deal fiercer, and he adds a warning that reads oddly for a natural history: it is not as timid as the cougar, and whoever ventures to attack it had better be well on his guard. Other missionary letters from those years are blunter. One describes an onza walking into a mission compound in broad daylight and attacking a boy of fourteen. Another has one killing the strongest and most respected soldier in the district.

Descriptions since have stayed remarkably consistent and remarkably relative. The onza is always measured against the mountain lion and always comes up wrong: slighter through the chest, longer in the ear, the legs noticeably thin and long enough to look almost canine at a distance, the tail long for the body, the coat a dusty grey-brown with faint barring low on the forelegs. Nobody has ever described an onza on its own terms. It is the other cat, the one that came out of the brush at the edge of the firelight and did not fit.

The name came from Europe rather than the sierra. Spanish onza descends from the Latin lynx, and it is the same word that gives English the ounce, the old name for the snow leopard. Mexican Spanish then spread it generously, so that in several states the jaguarundi is also an onza, while across the continent in Brazil the onça is simply the jaguar. There is a Nahuatl candidate as well, the cuitlamiztli, which Alonso de Molina’s 1571 dictionary glosses in four words as a large tawny lion. Whether that entry ever meant this animal specifically is a modern guess laid over a very short line, and it is worth saying so rather than pretending the identification is old.

On the first night of January 1986, a rancher in the San Ignacio district of Sinaloa was out after deer when a heavy cat came up out of the dark close enough that he took it for a jaguar preparing to charge. He shot it. What lay in the grass afterwards was not a jaguar, and to his eye it was not a puma either.

The animal was a female of about sixty pounds, forty-five inches from nose to rump with a further twenty-three inches of tail, and the legs really were long and thin. There was deer in her stomach and a torn wound on one hind leg that the men who examined her thought a jaguar had given her. Somebody had the good sense to freeze the carcass instead of skinning it for a wall. Tissue went north to Stephen O’Brien’s laboratory at the National Cancer Institute, where it was put through protein electrophoresis, albumin isoelectric focusing, twenty-eight restriction enzymes and a sequence of the mitochondrial ND5 gene, and compared against the felids of North America.

It was a mountain lion.

Everything the onza is credited with follows from what it is supposed to be, which is a puma with the caution taken out. It covers ground faster than an animal its size has any business covering, and it leaps distances that hunters describe by pointing at landmarks rather than giving numbers. It kills dogs, takes calves, and comes toward a man rather than away from him. There is nothing supernatural in the whole account, which is part of what makes it persuasive. The onza does not vanish, curse, shapeshift or speak. It simply refuses to behave the way a mountain lion behaves, and in a country where people have watched mountain lions all their lives, that is a serious accusation.

Its weakness is the strange part, and it is why the animal has never quite been caught. The onza dies as easily as any cat. That is exactly the problem. Every onza that has been shot, trapped, measured or photographed has turned back into a puma somewhere between the field and the laboratory, usually a lean female in a hard season, the sort of cat that carries no fat and looks impossibly long in the limb. The 1926 photographs are blurred and show a mountain lion. The skulls fall inside the mountain lion range. Robert Marshall gave the subject a whole book in 1961; Neil Carmony gathered every scrap of it into another in 1995 and concluded there was no real evidence for a distinct animal at all.

None of which has made the slightest difference in the sierra. The folklorist J. Frank Dobie collected an onza story that turned out, on inspection, to be about a were-onza, which is roughly the direction these things travel once the biologists have finished with them. What survives in Sonora and Sinaloa is not a species awaiting description. It is a category: the third cat, the one that shows up when the ordinary rules of the mountain do not hold, kept alive by ranchers who have seen a hundred lions and one animal that was not a lion.

Frequently Asked Questions

What is the Onza?

The Onza is a legendary big cat of northwestern Mexico, reported from Sonora, Sinaloa, Nayarit and the Sierra Madre Occidental. Local tradition counts three big cats in the mountains: the jaguar, the mountain lion, and the onza, which is described as lighter in build than a mountain lion, longer in the leg, and far more aggressive. It has been reported continuously since the eighteenth century without ever being confirmed as a distinct animal.

What does an Onza look like?

The Onza is always described in comparison to a mountain lion and always as the wrong version of one. Accounts give it a long thin body, unusually long and slender legs, longer ears, a long tail and a paler grey-brown coat, sometimes with faint barring low on the forelegs. No source describes it independently of the puma.

Is the Onza real?

No specimen has ever proved to be anything other than a mountain lion. A cat shot in the San Ignacio district of Sinaloa in January 1986 was frozen and its tissue analysed by protein electrophoresis and mitochondrial DNA sequencing at the National Cancer Institute; the results were indistinguishable from North American pumas. Neil Carmony’s 1995 survey of all the available onza material reached the same conclusion.

Where does the name Onza come from?

The word is Spanish, descended from the Latin lynx, lyncis, and shares a root with the English word “ounce”, once used for the snow leopard. In Mexico the same word is applied to more than one animal, including the jaguarundi in several states, and in Brazil onça means the jaguar. A Nahuatl word, cuitlamiztli, glossed by Alonso de Molina in 1571 as a large tawny lion, is sometimes linked to the onza, but that identification is a modern suggestion rather than a colonial one.

Does the Onza attack people?

That is the entire point of the tradition. Jesuit missionary accounts from eighteenth-century Sonora describe an onza entering a mission in daylight and attacking a fourteen-year-old boy, and another killing a soldier. Modern reports keep the same emphasis: the onza kills dogs and calves and moves toward people rather than away from them, which is what separates it in local telling from the ordinary mountain lion.

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