Within- and Between-Site Variability in Moustached Tamarin (Saguinus mystax) Positional Behavior during Food Procurement

Abstract

Despite evidence of marked seasonal changes in diet, day range, and patterns of habitat utilization in several primate species, little is currently known regarding intraspecific variability in locomotor behavior. In general, morphologists have tended to emphasize the constraints that anatomy places on positional behavior and have classified primate locomotion into a small set of broad categories such as leaping, suspension, and arboreal or terrestrial quadrupedalism. These categories have descriptive and functional value, but they typically have failed to include both the specific environmental context in which the behavior takes place (e.g., size, orientation, and rigidness of the support; location within the tree crown, etc.), or the relationship of positional behavior to the activity pattern of the animal (e.g., differences in patterns of posture and locomotion when exploiting particular food types). If one assumes that animals exploit substrates that allow them to move efficiently through the arboreal canopy, then there should be consistent associations between postural and locomotor behavior, support type, and activity pattern (Prost, 1965). How limited or how variable these associations are within a species is determined by physiological factors influencing body size and the energetic and mechanical costs of movement (Tuttle and Watts, 1985; Cant, 1987; Steudel, 1990, 1996; Doran, 1993); environmental factors affecting the structure of the arboreal canopy, and the spatial relationship of support types to each other and to the food resources exploited (Crompton, 1984; Garber, 1984, 1993a; Grand 1984; Pound, 1991; Cant, 1992; Bergeson, 1996); andsocial factors affecting individual spacing and differential access to resources of particular age, sex, or status classes (Hunt, 1992; Remis, 1995) (Figure 1).