The Mapinguari

The mapinguari is a large, hairy forest monster of Amazonian folk belief. The zoologist David Oren argued it may preserve a memory of giant ground sloths, an idea other scientists opposed.

Luís da Câmara Cascudo's Dicionário do Folclore Brasileiro describes the mapinguari as an enemy of people whose long hair turns bullets, except at the spot over its navel. It eats people, but only their heads. Cascudo cites Mário Guedes (1920), who heard from an old Indigenous chief that the former king of the region lived on inside the creature. He also gives a version from the Purus river recorded by J. da Silva Campos: a huge ape, as hairy as a spider monkey, with donkey's feet turned backwards, carrying the mangled body of a man's camp companion under its arm. Wikipedia says that as late as the twentieth century people believed it roamed the forests of Acre, Pará and Amazonas.

The zoologist David Oren, a former research director at Belém's Goeldi Institute, linked the story to real animals. In 1994 the Los Angeles Times reported his claim that a month-long expedition in Acre had turned up strong evidence that a giant ground sloth still lived. In 2007 he told the New York Times that people thousands of years ago met the final surviving ground sloths, and the legend grew from those encounters, and that whether one survives was a question science could not yet answer.

Brian Dunning of Skeptoid (2023) says other scientists opposed the idea at every turn, since Brazilian researchers would surely have noticed giant sloths in the forest. Dunning says Oren paid for his own expeditions, gathering stories in the hope of finding evidence.