Sloths are the general name for two families of the Xenarthra: a three-toed Bradypodidae and a two-toed Megalonychidae.

Xenarthra is a group of placental mammals. The group, differing in form and lifestyle, includes armadillos, glyptodonts, pampatheres, anteaters, tree sloths, ground sloths, and aquatic sloths.