Megatherium

Megatherium ( meg-ə-THEER-ee-əm; from Greek méga (μέγα) 'great' + theríon (θηρίον) 'beast') is an extinct genus of large ground sloths endemic to South America that lived from the Pliocene through the end of the Late Pleistocene. It is best known for the elephant-sized, 3.5–4 tonnes (7,700–8,800 lb) type species Megatherium americanum, which is primarily known from the Pampas, but which ranged southwards to northernmost Patagonia and northwards to southern Bolivia during the late Middle Pleistocene and Late Pleistocene. Various other species have been described, including those belonging to the Andean subgenus Pseudomegatherium, which range in size from comparable to M. americanum down to approximately 1 tonne (2,200 lb). The first (holotype) specimen of Megatherium americanum was discovered in 1787 on the bank of the Luján River in what is now northern Argentina. The specimen was shipped to Spain the following year, where it caught the attention of the French paleontologist Georges Cuvier. He named the animal in 1796, making it one of the first prehistoric animals to be scientifically named. Using comparative anatomy, he determined that Megatherium was a giant sloth. Megatherium is part of the sloth family Megatheriidae, which also includes the closely related and similarly-sized Eremotherium, which was native to tropical South America, Central America and North America as far north as the southern United States. Megatherium americanum is thought to have been a browser that fed on the foliage and twigs of trees and shrubs using a black rhinoceros–like prehensile upper lip (rather than a prehensile tongue as is often historically depicted). Despite its large body size, Megatherium americanum is widely thought to have been able to rear up on its hind legs while standing and braced, which allowed it to grasp and feed on high-growing leaves, and possibly to use its claws for defense. Megatherium became...