Ancient sloths lived in trees, on mountains, in deserts, boreal forests and open savannahs. These differences in habitat are primarily what drove the wide difference in size between sloth species. But ...

New studies by two research teams published today in the journals Nature Ecology and Evolution and Current Biology challenge decades of accepted scientific opinion concerning the evolutionary ...

Ancient sloths lived in trees, on mountains, in deserts, boreal forests and open savannahs. These differences in habitat are primarily what drove the wide difference in size between sloth species.

Deep in the unyielding darkness of a Brazilian cave, a pale, blind, spiny beast carefully feels its way across rust-colored rocks. Meet Paleotoca diminas, a spider new to science. The species, ...