Based on Bru's illustrations, comparative anatomist Georges Cuvier determined the relationships and appearance of "Megatherium". He published his first paper on the subject in 1796, a transcript of a previous lecture at the French Academy of Sciences. He published on the subject again in 1804; this paper was republished in his book "Recherches sur les ossemens fossiles de quadrupèdes". In his 1796 paper, Cuvier assigned the fossil the scientific name "Megatherium americanum". Cuvier determined that "Megatherium" was a sloth, and at first believed that it used its large claws for climbing trees, like modern sloths, although he later changed his hypothesis to support a subterranean lifestyle, with the claws used to dig tunnels.