Recording spider monkeys with a microphone array

Abstract

The potential of using a GPS-linked microphone array [J. Acoust. Soc. Am. 109, 434–437 (2001)] to monitor spider monkeys (Ateles geoffroyi) In the rainforest of the Yucatan peninsula, Mexico, was assessed. This species is of concern for conservation because of their requirement of large areas of relatively undisturbed tropical forest. The array was composed of six independent nodes. Each node consisted of a DAT recorder, a microphone, a GPS receiver and a small computer. The GPS data, containing both timing and location information, was converted into an audio signal and recorded on the tape parallel to the microphone signal. In this manner the recordings were synchronized and the receiver locations logged. The recordings were used to locate vocalizing monkeys. We measured the apparent source level and directionality of monkey vocalizations, and the transmission loss through the rain forest canopy. The system has a potential for studying the behavior of spider monkeys, as well as other sound-producing animals. This could have useful applications for the monitoring of important species for conservation. [Work supported by the Danish National Research Council and Pronatura, Mexico.]