Arboreal adaptations

Abstract

Abstract The Paleocene began with empty arboreal niches in recovering forests. Stem primates, called plesiadapiforms, exploited these habitats via specializations like those of arboreal rodents. During the Eocene, many animals exploited the rainforests of northern continents, but primates did so differently. A suite of adaptations coalesced in early primates: skeletal and muscular mechanisms for pedal and manual grasping of branches and items on them; fingernails, toenails, and papillary ridges on fingers and toes to secure a precisely calibrated grip; a hindlimb-dominated, leaping–grasping mode of locomotion suited to movement among flimsy and discontinuous branches; a new kind of gait suited to arboreal life; and forward-facing eyes, along with other changes in vision. Primates became “visual animals,” which reversed the de-emphasis of vision that evolved in Mesozoic mammals.