Eastern Kentucky University
Monitoring Howling Monkey Ranging Behavior Using Vocalizations in Ometepe, Nicaragua
Institution
Eastern Kentucky University
Faculty Advisor/ Mentor
Ben Freed
Abstract
Researchers have suggested that folivorous primates in secondary growth forests, compared with those in primary growth forests, have greater intergroup distance and daily path length. To test this hypothesis, population surveys of mantled howling monkeys (Alouatta palliata) were conducted July, 2011 on Ometepe Island, Nicaragua in both undisturbed primary forest and reclaimed secondary forest. The two forest types are largely representative of common environments howlers inhabit. Triangulation of predictable vocalizations (the "dawn chorus", a spacing mechanism), combined with ground censuses, were used to determine the daily location and size of six howler groups. Groups in the secondary forest were larger than those in the primary forest, but the female / male ratio for all groups surveyed was similar (between 2:1 and 5:1). Spacing was approximately 300 meters between groups in the undisturbed primary forest, and 400 meters between groups in the secondary forest. Daily path length averaged nearly 25 meters per day, much smaller than that normally reported for A. palliata. Overall, intergroup spacing significantly increased in secondary forests. Daily path length, however, was much smaller than the estimated 400 meter figure in previous research on A. palliata in secondary forests.
Monitoring Howling Monkey Ranging Behavior Using Vocalizations in Ometepe, Nicaragua
Researchers have suggested that folivorous primates in secondary growth forests, compared with those in primary growth forests, have greater intergroup distance and daily path length. To test this hypothesis, population surveys of mantled howling monkeys (Alouatta palliata) were conducted July, 2011 on Ometepe Island, Nicaragua in both undisturbed primary forest and reclaimed secondary forest. The two forest types are largely representative of common environments howlers inhabit. Triangulation of predictable vocalizations (the "dawn chorus", a spacing mechanism), combined with ground censuses, were used to determine the daily location and size of six howler groups. Groups in the secondary forest were larger than those in the primary forest, but the female / male ratio for all groups surveyed was similar (between 2:1 and 5:1). Spacing was approximately 300 meters between groups in the undisturbed primary forest, and 400 meters between groups in the secondary forest. Daily path length averaged nearly 25 meters per day, much smaller than that normally reported for A. palliata. Overall, intergroup spacing significantly increased in secondary forests. Daily path length, however, was much smaller than the estimated 400 meter figure in previous research on A. palliata in secondary forests.