A novel approach to studying enclosure and support usage in siamangs: using a 3D computer model

Abstract

The objectives of this study were: (1) to evaluate the accuracy of a computer-aided design (CAD) approach in recording the full 3D geometry of a zoo primate enclosure, (2) to quantify support availability and preference, and map behavioural data within the 3D enclosure model to visualise/identify/investigate spatial enclosure usage trends. 3D models of a siamang (Symphalangus syndactylus) enclosure were created using a generic CAD approach and a long range laser scanner (LiDAR). It was determined that the CAD model yielded an average geometric error of ~15% in terms of position/height/diameter of structures relative to the LiDAR model. The CAD model was divided into zones to create colour maps of enclosure usage during feeding/travel/inactivity. For feeding and inactivity, average support availability was higher in zones most used when compared to zones used least. Electivity indexes, a measure of support preference within a particular zone, permitted us to explore why specific supports were preferred over others in the immediate proximity. Electivity indexes were higher for strong horizontal initial supports (mainly logs) during richochetal brachiation. This suggests a need for a strong horizontal support to generate sufficient propulsive force during push off, to create the flight phase characteristic of richochetal brachiation.