Vertical clinging and leaping in a neotropical anthropoid

Abstract

NAPIER and Walker¹ proposed a new category of primate locomotor behaviour which they called “vertical clinging and leaping”. They believed that among living primates this category included only certain prosimians. It has since been recognised that non-prosimian primates (for example, Saquinus², Cacajao³, and Callicebus⁴) may at times also leap to and from postures in which the body is held vertically at rest. In a recent review of vertical clinging and leaping Stern and Oxnard suggest that “future behavioural observations will show that almost all primates may occasionally move in this way”³. In view of the acrobatic arboreal abilities of primates this would not seem remarkable, given appropriate environmental conditions and stimuli. So far, however, no one has reported any anthropoid primate engaging habitually in this form of positional⁵ behaviour.