Locomotion, Posture, and Feeding Behavior of Kinkajous, Coatis, and Raccoons
Many arboreal mammals use their forelimbs and forepaws for food handling and for locomotion.
To investigate the relations between these major categories of limb use, I examined the locomotor behaviors, food handling, and postures of three arboreal procyonid carnivores, kinkajous (Potos flavus), coatis (Nasua narica and N. nasua), and raccoons (Procyon lotor). The characteristics shared by these three species include occasional to frequent bipedalism (sitting and standing) and the ability to reverse the hind feet at least partially during climbing. The major differences between taxa are in footfall patterns and food handling behaviors. The frugivorous kinkajous grasp objects with a single-handed coverging grip, hang upside down with fully reversed hind feet, display remarkable vertebral flexibility, and possess a prehensile tail. All these traits permit kinkajous to feed effectively from terminal branches. Their crouched posture and an unprecedented variety of footfall patterns are not directly related to feeding behavior, but rather to climbing ability. Coatis and raccoons find most of their food on the ground. Postures and use of the forepaws during feeding are suitable for terrestrial conditions, but appear to compromise their arboreal performance. Coatis are excellent diggers and shredders, but have little fine control of digit movements; these traits, and their musculoskeletal correlates, preclude the grasping ability and terminal branch feeding seen in kinkajous. Raccoons possess exquisite fine control of forepaw digits, but do not have the converging grasp of kinkajous. Their semidigitigrade forelimb posture reduces the surface area of forefoot contact with the substrate and may adversely affect their ability to negotiate slender supports.