Mono Grande

Pronounced MOH-noh GRAHN-deh

The Upright Ape of the Tarra River

“A tailless, man-sized ape said to walk upright through the deep jungle, immortalized by a single disputed 1920 photograph.”

The Mono Grande — the 'big monkey' — is South America's contribution to the world's wildman files: a large, tailless, upright-walking ape reported from the forests of Venezuela and its Colombian borderlands, where no great ape has any business existing. The stories are older than the evidence; Alexander von Humboldt heard Orinoco tales of the hairy, man-like 'salvaje' in the early nineteenth century and dismissed them as myth.

What made the creature famous was a single photograph. In 1920, Swiss oil geologist François de Loys claimed his expedition shot a large, tailless primate on the Tarra River, and the image — a dead animal propped on a crate, a stick under its chin — was launched into science in 1929 as Ameranthropoides loysi. The identification collapsed under scrutiny into one of cryptozoology's best-documented frauds, yet the Mono Grande refuses to leave the literature.

The Legend

Long before any camera reached the region, the peoples of the Orinoco told of the salvaje — a furry, human-like creature of the deep forest said to carry off women, build huts, and occasionally eat human flesh. Humboldt recorded and rejected the stories; the naturalist Philip Gosse looked into similar legends in Venezuela in the mid-nineteenth century without result. The 'king monkey' was folklore's property first.

De Loys's tale gave the legend its modern shape. His 1917-1920 oil survey near Lake Maracaibo was a catastrophe — disease and violent clashes left only four of twenty men alive — and by his account, at the Tarra River two large, red-furred, tailless primates confronted the party, shrieking, brandishing their arms, and flinging their own excrement. The men fired; the female fell. De Loys claimed she stood 1.57 meters tall with thirty-two teeth and no tail, and that everything but one photograph was later lost.

Documented Sightings

The 1920 Tarra River encounter remains the anchor case, entering the public record when the anthropologist George Montandon found the photograph in de Loys's files and had it published in the Illustrated London News on June 15, 1929, proposing the species Ameranthropoides loysi. The scientific reception was immediate and hostile: Sir Arthur Keith noted the photo gave no reliable scale and suggested a common spider monkey was being passed off as something exotic.

Later reports kept the file open without improving it. In 1951 the Frenchman Roger Courteville claimed his own ape-man encounter at the very same Tarra River and produced a photograph — promptly denounced as a manipulated fake. The American primatologist Philip Hershkowitz, who worked the same country in the 1940s, concluded the Mono Grande was a myth grown from the spider monkey, and sighting claims attributed to Venezuela, Colombia, and Guyana have never yielded a specimen.

The Lore

The debunking is now the better story. Uncropped prints of de Loys's photograph show cut banana stalks — cultivated plants that do not belong in untouched jungle. In 1962 the Venezuelan physician Enrique Tejera, who had known de Loys in the field, wrote a letter finally published by the journal Interciencia in 1999: 'this monkey is a myth,' he said — de Loys had kept a pet spider monkey whose tail had been amputated, and it died on their travels. The likely model was a white-bellied spider monkey, Ateles belzebuth, a beast of about 110 centimeters, not 157.

The fraud had an ideology. Montandon promoted a racist 'hologenesis' of humanity in which different peoples descended from different apes, and an American ape was the missing prop for his scheme — historians Centlivres and Girod anatomized the affair in 1998. Stripped of the photograph, the Mono Grande reverts to what it was before 1920: the salvaje of Orinoco folklore, still reported now and then from the high forests, and still the best South American argument that legends photograph poorly.

Field Notes

✦ The De Loys photograph is the most cited and most thoroughly debunked evidence.
✦ Described as bipedal, aggressive, and far larger than known local monkeys.
✦ Range claims span Venezuela, Colombia, and Guyana; no specimen has ever surfaced.
✦ Uncropped prints betray cut banana stalks at the supposedly untouched jungle site.
✦ A 1962 letter by Dr. Enrique Tejera identified the ape as a pet spider monkey with a docked tail.

Case File

Classification: Unknown great ape
Category: Humanoid/Wildman
Territory: Sierra de Perijá and Orinoco basin
First Sighted: Early 1800s (salvaje tales heard by Humboldt)
Habitat: Remote rainforest and mountain jungle
Reported Size: ~1.5 m (5 ft) or larger
Also Known As: De Loys' Ape · Mono Rey · Big Monkey