Ground sloth
A diverse group of extinct sloths adapted to terrestrial life, ranging from small forms to elephant-sized species that lived in the Americas.
Sloth: A group of slow-moving mammals in the order Pilosa, including living tree sloths and extinct terrestrial relatives. Ground sloths are the terrestrial branches of the wider sloth lineage.
Megatherium: A genus of giant ground sloths from South America, including some of the largest known sloths. Its immense size makes it the best-known example of a ground sloth.
Quadrupedalism: A mode of locomotion using all four limbs for support and movement. Most ground sloths moved on four limbs, though some could rear upright.
Great American Biotic Interchange: The exchange of terrestrial animal lineages between North and South America after the continents became connected. Ground sloths dispersed northward during this major episode of faunal exchange.
Quaternary extinction event: The widespread loss of large-bodied animal species during the late Pleistocene and early Holocene. Ground sloths were among the large mammals lost in the Americas.
Xenarthra: A mammal group that includes sloths, anteaters, and armadillos, distinguished by features including extra articulations in the vertebrae. This broader lineage places sloths among their closest living mammal relatives.
Megalonyx: A genus of ground sloths from North America, named by Thomas Jefferson in 1797. This North American genus figured in early scientific debates about fossil mammals.
Bipedalism: Locomotion on two legs, used habitually or temporarily by an animal. Strong hind limbs and a massive tail let some ground sloths rear to reach vegetation.
Santa Cruz Formation: An early Miocene fossil-bearing geological formation in Patagonia, Argentina. Its fossils document diverse early sloth lineages in South America.
Pleistocene megafauna extinctions: The late Pleistocene disappearance of many large animal species across multiple continents. Ground sloth extinction is part of this broader, debated pattern.