Tails of Macaques: Similar Length but Different Movement? Focusing on Rhesus (Macaca mulatta), Northern Pig-tailed (M.leonina) and Assamese Macaques (M. assamensis) (#627)
Macaques are primates which mainly distribute in Asia. They have various tail length from 2 to 122% of their head and body length but they are not prehensile. We have investigated morphological study of caudal vertebrae in several species of macaques, and found out that though rhesus, northern pigtailed and Assamese macaques have similar relative tail length (35~45%), the number of caudal vertebrae and each length were different from each other. Accordingly we assumed that the movement of their tail may have difference or species specific usage pattern and have done behavior observation of each species, provisioned wild group, in Thailand. By focal animal sampling method the movement of tail, positional behavior and social communicative behavior were recorded. Video records were also taken by ad lib sampling method. As a result in rhesus macaque, the high ranked individual shows its status by raising the tail vertically from the line of back bone. When they run they stretch their tail horizontally and when they sit on a branch they wraps their tail to the branch to support. In northern pig-tailed macaque, juveniles move their tail as they jump around branches to take balances. Though in adult alpha-males they keep its tail raised up that nearly sticks up its back thus this usage is more communicative than balance taking. In Assamese macaque, we could not see the special tail position for the high ranking individual. But the vertically raised tail was often seen while juvenile or lower ranked individual approaches to some place with nervousness such as feeding point. From the observation, the three species have moving region restriction by caudal vertebrae morphology and have species’ specific usage.