Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. Ground sloths varied widely in size, with the largest, belonging to genera Megatherium and Eremotherium, being around the size of elephants. Ground sloths are a paraphyletic group, as living tree sloths are thought to have evolved from ground sloth ancestors.
Fossil Eremotherium skeleton, National Museum of Natural History, Washington, DC.
Paramylodon harlani, Texas Memorial Museum, University of Texas at Austin
A Tamandua anteater in an upright defensive stance similar to those presumed to have been adopted by ground sloths, per trackways preserved in New Mexico
The Late Pleistocene to the beginning of the Holocene saw numerous extinctions of predominantly megafaunal animal species, which resulted in a collapse in faunal density and diversity across the globe. The extinctions during the Late Pleistocene are differentiated from previous extinctions by the widespread absence of ecological succession to replace these extinct megafaunal species, and the regime shift of previously established faunal relationships and habitats as a consequence. The timing and severity of the extinctions varied by region and are thought to have been driven by varying combinations of human and climatic factors. Human impact on megafauna populations is thought to have been driven by hunting ("overkill"), as well as possibly environmental alteration. The relative importance of human vs climatic factors in the extinctions has been the subject of long-running controversy.
Late Pleistocene in northern Spain, by Mauricio Antón. Left to right: wild horse; woolly mammoth; reindeer; cave lion; woolly rhinoceros
Mural of the La Brea Tar Pits by Charles R. Knight, including sabertooth cats (Smilodon fatalis, left) ground sloths (Paramylodon harlani, right) and Columbian mammoths (Mammuthus columbi, background)
The proportion of extinct large mammal species (more than or equal to 10 kg (22 lb)) in each country during the last 132,000 years, only counting extinctions earlier than 1000 years BP
Giant tapir (Tapirus augustus) restoration