Jon Pauli is perched in the passenger seat of a mud-spattered Ford F-250. His ceramic mug brims with coffee as graduate student Evan Wilson guides […]

1) A sloth is not a sloth. There are two types of tree sloths that diverged roughly 20 million years ago—two-toed and three-toed sloths, so […]

As forests in South America and Central America are cleared for agriculture and other human uses, sloths are running out of room to maneuver.