Vertical Clinging and Leaping - A Newly Recognized Category of Locomotor Behaviour of Primates

Abstract

This paper provides a preliminary account of a natural locomotor group among the Primates. All the living members of the group are prosimians, they include. Tarsius, Indri, Propithecus, Avahi, Lepilemur, Hapalemur simus, Galago, Euoticus. The animals concerned were arboreal and had a vertical clinging posture at rest, and were well adapted to a leaping mode of progression during which the hindlimbs, used together, provide the propulsive force. The special interest of this locomotor group of vertical clinging and leaping was that it appeared in a preliminary study to constitute the only known locomotor adaptation of Eocene primates such as Notharctus, Necrolemur, Smilodectes, etc. Possibly it is to be regarded as the earliest locomotor specialization of primates and therefore preadaptive to quadrupedalism, brachiation and bipe-dalism, the principal locomotor categories of living primates.