Bears fall into three living subfamilies. The Ursinae contains the brown, black, polar, sloth and sun bears; the Ailuropodinae contains only the giant panda; and the Tremarctinae, the short-faced bears, contains only the spectacled bear. The rest of the Tremarctinae, including Arctodus of North America and the very large Arctotherium of South America, disappeared at the end of the Pleistocene.
The surviving species lives in the Andes and eats mostly plants. Bromeliads, particularly the tough hearts of terrestrial species, along with palm hearts, fruit, bamboo and cactus, dominate its diet; meat is a small and irregular component. To reach fruit and bromeliads it climbs well and builds nest-like platforms of broken branches in trees, which surveyors use as an indirect sign of presence.
The facial markings are individual, ranging from full rings around both eyes to faint patches or nothing at all, which makes camera-trap identification possible. Population estimates for the species remain coarse because the terrain is steep, forested and hard to survey, and totals quoted for the Andes as a whole should be read as approximations rather than counts.