De Loys’ Ape, given the proposed scientific name Ameranthropoides loysi, was an alleged large primate reported by Swiss geological explorer François de Loys in South America. The only evidence for the animal besides de Loys’ testimony is one photograph. It was promoted by George Montandon [fr] as a previously unknown species, but is now usually considered a misidentification of a spider monkey species or a hoax.
Encounter

François de Loys, a Swiss oil geologist, led an expedition from 1917 to 1920 to search for petroleum in an area along the border between Colombia and Venezuela, primarily near Lake Maracaibo. The expedition was unsuccessful, and furthermore suffered greatly due to disease and skirmishes with natives; of the 20 members of de Loys’ group, only four survived.
According to de Loys’ later report, in 1920, while camped on a bank of a tributary of the Tarra River, two large creatures approached the group. Initially, de Loys thought they were bears, but then noted that they were monkey-like. The creatures – one male, one female – seemed angry, said de Loys, and advanced howling and gesturing, breaking and holding branches, and then defecating into their hands and flinging feces at the expedition. Fearing for their safety, the expedition fired at the pair, killing the female and wounding the male; the wounded male then fled. De Loys and his companions recognized that they had encountered something unusual. The animal resembled a spider monkey, but was much larger: 1.57 m tall (compared to the largest spider monkeys, which are just over a meter tall). De Loys counted 32 teeth (most New World monkeys have 36 teeth), and noted that the creature had no tail.
They posed the creature by seating it on a crate and propping a stick under its chin. After taking a single photograph, de Loys reported, they skinned the creature, intending to keep its hide, skull, and jaw, but the items were later abandoned by the troubled expedition.
According to other reports, more photographs were taken but were lost either in a flood or during the capsizing of the scientists’ boat.
Publication
After de Loys returned to Europe, the story was not reported until 1929, when his friend George Montandon discovered the photograph while perusing de Loys’s files for information about South America’s native tribes. At Montadon’s urging, De Loys related his account in the Illustrated London News of June 15, 1929, and three articles regarding the creature were published in French journals. Montandon suggested the scientific name Ameranthropoides loysi, and proposed it as the ancestor of Native Americans in support of his “Hologenesis Hypothesis”, which suggested different racial groups of homo sapiens evolved independently from different non-human ape species rather than sharing a common human ancestor. This hypothesis was popular at the time, but now many regard it as nothing but the product of racist and discriminatory views Motandon held.
Controversy
After this publicity, de Loys’ account was deemed unreliable by several critics, notably Sir Arthur Keith, a prominent anthropologist. Keith suggested de Loys was trying to pass off a normal spider monkey as something more exotic. The photograph did not clearly indicate the creature’s size, and Keith also noted that by not photographing the creature’s posterior, de Loys had left open the question of whether or not it had a tail. Keith suggested the animal in the photo was simply a spider monkey.
Most later writers have agreed that the creature in the photograph is a spider monkey. Others, such as the cryptozoological researcher Ivan T. Sanderson suggested the white-bellied spider monkey (Ateles belzebuth) as most similar in appearance and shape. Sanderson further noted that the particular area in which de Loys allegedly encountered the ape had no history of reports of oversized primates. He regarded the identification as an unknown ape “an outright hoax, and an obnoxious one at that, being a deliberate deception.”
Other researchers, such as cryptozoologists Loren Coleman and Michel Raynal, also support the theory that the creature is a hoax based on a photograph of a spider monkey, and argue that Montandon was the perpetrator. Montandon used the Ameranthropoides loysi to support his view that the human races had independently evolved from different primates found in their regions. He had previously argued that the white race had evolved from early Homo sapiens, while Africans evolved from gorillas and Asians from orangutans; he proposed the Ameranthropoides loysi was a “missing link” ancestor to the Indigenous peoples of the Americas.
Since then, research has come to light, noted on Coleman’s blog, suggesting that the stump of a banana tree can be seen at the right side of the entire photograph. Bananas are not indigenous to South America, making their occurrence in the remote jungle highly implausible, thus making it probable that the photo was not shot at the location de Loys indicated. This argument and other findings which strongly indicate a hoax, largely the result of Spanish-language work by Venezuelan scientists Bernardo Urbani and Angel Viloria, were essentially unknown to cryptozoology researchers prior to the summer of 2007. In 2009, Urbani and Viloria translated and published their findings in English.
Of those who believe de Loys encountered an unknown species, some suggest it was a surviving Protopithecus brasiliensis, a large spider monkey of the Pleistocene epoch, or connect it to the legend of the “Mono Grande” reported in the area later in the 20th century.