Postural behavior of wild aye-ayes in Madagascar’s Ihofa Forest

We studied an adult female and a juvenile male aye-aye (Daubentonia madagascariensis) in Madagascar's Ihofa forest from May to December 2017 to investigate whether the postural diversity of this lemur varied with age, maintenance activity, and habitat use. We used bout sampling (female N = 488, male N = 355) to record postures during feeding and resting and tested for differences using χ 2 . For both individuals, bimanual and unimanual cling were the most common postures used during feeding (78.4% and 82.9%) and these behaviors were strongly associated with the use of vertical supports - trunks and bamboo - in the main canopy. When feeding on branches and boughs, pronograde postures such as tri-pedal crouch and crouch were most common. Most rest occurred on horizontal branches using primarily pronograde postures. Our data indicate that although aye-ayes exploit multiple forest strata, the great majority of feeding is accomplished using orthograde postures from vertical supports, even in forest strata dominated by horizontal supports. These findings support recent arguments about the significance of vertically oriented behaviors in the evolution of early mammalian arboreal quadrupeds.