Positional behavior ofCebuella pygmaea in Yasuni National Park, Ecuador

Abstract

In terms of positional behavior, the small-bodied callitrichids are distinguished from other anthropoids by their ability to leap between and to cling to large vertical supports, feeding occasionally or frequently on sap and bark insects. In this paper, I studied the positional behavior of a group of pygmy marmosets in a hilly wet tropical forest in Yasuni National Park, Ecuador. During traveling, the animals used quadrupedal walk/bound and leaping mostly on small horizontal supports. During foraging, quadrupedal walk/bound and clambering dominated. The main foraging postures were stand and cantilever, occurring mainly on small horizontal lianas. During feeding, scansorial locomotion was used very frequently. Claw clinging was the dominant feeding posture. Furthermore, large vertical lianas and tree boles were the most frequent feeding supports. These observations would suggest that scansorial locomotion, vertical clinging, and vertical leaping are most likelynot part of the same form function complex. Vertical leaps appear to be associated with moving in the lower parts of the forest. On the other hand, scansorial locomotion and vertical clinging appear to be related to feeding on the sap of tree boles and large lianas in the lower parts of the forest.