Abstract # 239:

Scheduled for Saturday, August 19, 2006 02:15 AM-02:30 AM: Session 23 (Regency East #2) Oral Presentation

The Effects of Fruit Availability on the Diet and Ranging Behavior of the Black Howler Monkey (ALOUATTA PIGRA) of Monkey River, Belize

G. R. Bridgett and M. S. M. Pavelka
University of Calgary, Department of Anthropology, 2500 University Drive N.W., Calgary, AB T2N 1N4, Canada
     It has been suggested that Central American black howler monkeys (ALOUATTA PIGRA) preferentially consume fruit over leaves. Therefore, we hypothesized that the availability and distribution of fruit would have an effect on the diet and ranging patterns of A. PIGRA. 290 hours of focal observations were collected on 4 howler groups at Monkey River, Belize from May to December of 2004 and the phenophase of 201 trees representing important food species was monitored to quantify the availability of fruit. The Universal Transverse Mercator coordinates of trees utilized were entered into ArcGIS v. 8.01® to create maps of home ranges and quantify day journey length and fruiting tree distribution. Multiple regressions were used to examine the effect of fruit availability and distribution on diet and ranging. Availability of fruit varied over the study period and was positively correlated with fruit in the diet (R2 = 0.36, p < 0.05) while only ripe fruit availability was correlated with day journey length (R2 = 0.08, p < 0.05). When fruiting trees were more clumped in distribution, there was no effect on diet, but day journey length decreased (R2 = 0.11, p < 0.05). The study groups appeared to use some foraging strategies, such as pivotal trees, when exploiting fruit sources but instances of goal-directed travel were rare. The importance of fruit in the diet and ranging of black howlers may have implications for our understanding of their apparently dispersal egalitarian social structure.