The grasping behaviour, locomotion and substrate use of the tree shrews Tupaia minor and T. tana (Mammalia, Scandentia)

Abstract

The grasping behaviour, locomotion and substrate use of the tree shrews Tupaia minor and T. tana were investigated in the Department of Zoological Research at the National Zoological Park in Washington, DC. Seven arboreal T. minor and five terrestrial T. tana were observed and videotaped for 10-min focal animal samples totalling 77 h of observation. Locomotion and substrate use were scored and images of grasping behaviour were captured from videotapes. Tupaia minor individuals were videotaped crossing dowels and the number of dowel crossings that included grasps were scored. In 84% of dowel crossings, T. minor individuals used either their hallux or their pollex to grasp the dowels. Tupaia minor was also more active, moved more quickly, was more arboreal, rooted less, reversed its feet more, flexed its forelimbs more and was more semi-plantigrade than T. tana. It is proposed that arboreal tupaiids, such as Ptilocercus lowii and T. minor, may represent better models for early primates than didelphid marsupials because they are capable of grasping and are more closely related to primates.