Substrate use: typical postures and locomotion. a: sitting on top of the substrate is the usual posture for resting.
b, c: suspended postures, with both feet attached to the substrate, are frequent. d: walking on top of more or less horizontal substrate is the preferred way of moving. e: bipedal stand allows use of the hands for handling of objects. The animal pictured here clearly disliked standing upright on a horizontal board without bending the toes of at least one foot around the edge for safe hold (redrawn after a photo by Tardieu). f: Bipedal postures also allow reaching for distant branches or prey. f, g: "bridging" over substrate gaps. h-j: vertical substrates are mainly used for locomotion upwards and downwards (both head first). The animals prefer thin branches which allow a safe grip (h). When climbing up and down large trunks (i), the animals need a rough surface to which they can cling.