Meeting Abstract
Different sympatric species of tamarins in Amazonian Peru form mixed-species groups during daily forages in the rain forest. These closely-related species have previously been documented to exhibit differences in foraging height and locomotor activity which may also be reflected in their postcranial morphology. To further investigate this system, we quantified habitat utilization with a focus on leaping behavior in free-ranging Saguinus mystax and Leontocebus nigrifrons . The aim of the work was to determine the relationship of leaping behavior with habitat use and how this is determined by the properties of the habitat. We collected data on the leaping behavior, support properties, and foraging height of the monkeys during a 5-month field study in the Amazonian in northeastern Peru at the Estación Biológica Quebrada Blanco. Our results showed that S. mystax spends significantly more time in the upper forest strata and uses the predominant supports at a noticeably higher rate than L. nigrifrons . In contrast, L. nigrifrons is predominantly active in the lower forest strata and accordingly exhibits a high number of trunk-to-trunk leaps. However, both species preferred their predominant leaping behavior even if the respective supports were not abundant in a specific forest layer. We hypothesize that these observed behavioral differences also involve differential functional demands caused by kinematic and dynamic differences in horizontal and vertical leaps, respectively. Based on these findings morphological differences in muscle architecture, bone shape, and bone structure can be expected and will be traced down in ongoing analyses.
