De Loys' Ape
Aliases: Ameranthropoides loysi / Territory: Venezuela, Colombie
The 1920 'American ape' photo: a staged spider monkey, later weaponised by racist anthropology — a demonstrated hoax.
The whole case rests on one photograph: a primate seated on a wooden crate, propped upright with a stick under its chin, hands on its thighs. François de Loys, a Swiss geologist who survived a calamitous 1917-1920 oil survey along the Tarra River, where the Perijá range straddles the Venezuela-Colombia border, later claimed two aggressive creatures had rushed his camp, screaming and flinging their own excrement, and that his men shot the female. He put her at 1.57 metres and — the crucial detail — tailless. The skin and skull he said were kept had conveniently been lost in transit. Only the picture remained.
The image might have stayed in a drawer. Instead, around 1929 the Franco-Swiss anthropologist George Montandon found it among de Loys' papers and carried it to the Paris learned societies and the illustrated press, christening the animal Ameranthropoides loysi — 'Loys' American ape'. His eagerness was not disinterested: Montandon championed a polygenist doctrine in which each human 'race' descended from a different continental ape, and an American anthropoid gave him the missing link he needed to assign Indigenous Americans a separate lineage. It was zoology pressed into openly racist service, by a man who would later distinguish himself as an active antisemite under the Occupation.
Scientists were largely unpersuaded from the start. As early as 1929, critics — the British anatomist Arthur Keith among them — pointed out that the photograph shows an ordinary spider monkey (genus Ateles), abundant in that very region: the proportions, the face, the reduced thumb all match. The tail, the one organ that would have settled the question, is precisely what the framing and the crate conceal. Nothing in the image gives scale, and a banana plant — a cultivated species — betrays proximity to human settlement rather than the untouched jungle of the tale.
The closing document surfaced late. In a 1962 letter, published in 1999 by the Venezuelan geologist Franco Urbani, the physician Enrique Tejera — who had known the expedition first-hand — explained that the animal was a tame spider monkey kept as a mascot, its diseased tail amputated, and that the whole business had been a joke. The 'great ape of the Americas' is thus doubly resolved: a staged photograph, and a posthumous career manufactured by its promoter's ideology. It survives in textbooks as a case study — not in primatology, but in how photographic 'evidence' can be abused.
+ Notable reports
// Tarra River, Perijá range (Venezuela-Colombia border)
In de Loys' telling, two aggressive primates attacked his camp; the female was shot and photographed seated on a crate, a stick propping her chin. The skin and skull supposedly retained never reached anyone.
// Paris
George Montandon presented the photograph to learned societies and named the creature Ameranthropoides loysi, enlisting it in his racist doctrine of separate human origins. Anatomists, including Arthur Keith, immediately recognised a staged spider monkey.
// Caracas, Venezuela
A letter by physician Enrique Tejera, published by Franco Urbani, revealed the animal was a tame spider monkey with an amputated tail and the affair a prank — the insider testimony that formally closed the file.
+ Leading rational explanations
- A staged spider monkey (Ateles): anatomy identified as early as 1929, tail hidden by the framing
- Total absence of physical evidence: no skin, no skull, no scale reference in the photograph
- A banana plant in frame betrays a settled area, contradicting the untouched-jungle narrative
- Enrique Tejera's 1962 account: a tame, tail-amputated pet passed off as a discovery in jest
Status note
Class 5: a demonstrated hoax — the spider monkey identified anatomically, the staging established, and insider testimony confirming the trick, later exploited for ideological ends.
+ Frequently asked questions
- Is the De Loys' ape photograph genuine?
- The photograph is real, but it shows a common spider monkey posed on a crate with its tail out of frame. The anatomy was identified as early as 1929, and a witness letter by Enrique Tejera later confirmed the animal was a tame pet and the story a joke.
- Why does this case have a racist dimension?
- Anthropologist George Montandon promoted the photo to support his claim that each human 'race' descended from a different ape — Indigenous Americans from an American anthropoid. That pseudo-scientific agenda, now universally rejected, is the real reason the picture became famous.
- Are there any great apes in South America?
- No: no great ape has ever been documented in the Americas, living or fossil. The continent's largest primates are prehensile-tailed monkeys such as spider monkeys and woolly monkeys — which is exactly what the photograph shows.