Megatherium americanum - The Giant Ground Sloth
The skeleton of Megatherium set up in the London Natural History Museum, and a depiction of a possibility of Megatherium behavior in life.
Though the population was already decreasing when the first humans arrived in South America, the disappearance of the Giant Sloth was helped along by the new immigrants. Using mammoth-hunting skills, this large and lumbering creature was an ideal kill for a human tribe. It was one of the many Pleistocene megafauna that went extinct during the Quaternary extinctions.
Extinct monsters. H. N. Hutchinson, 1896.