Abstract # 943 Event # 107:

Scheduled for Friday, August 19, 2005 09:30 AM-09:45 AM: Session 8 (Mayfair Room) Oral Presentation

Proximity patterns among age-sex classes in free-ranging Central American black howlers (Alouatta pigra)

L. C. Corewyn and M. Pavelka
, Department of Anthropology, University of Calgary, 2500 University Dr. NW, Calgary, Alberta T2N 1N4, Canada
     Like many folivorous species, Alouatta pigra appears to exhibit low levels of overt social interaction, thus proximity between group members may represent one of the few observable expressions of their underlying social relationships. From July 2003 to January 2004, I studied the proximity patterns of adults and juveniles in 3 groups (n = 2 to 6) of A. pigra, totaling 161 hours of focal animal data. At the beginning of each focal animal sample, a proximity scan (n = 971) was used to record all neighbors in three proximity categories: within 2m; > 2m but within the same tree; and no neighbors in the same tree. Data were analyzed at the age-sex level as individual identification was not always possible. Results revealed that, overall, focal individuals had their closest neighbor within 2m in 70.7% of scans, suggesting a high degree of social affiliation. Adult females had their closest neighbor within 2m more frequently than adult males (73.1% of scans vs. 65.9% respectively), though differences were not significant (χ2 = 1.921, df = 2, P = 0.383). Adult females were more frequently within 2m of adult males than other adult females (53.3% of scans vs. 47.4%, respectively; χ2 = 5.553, df = 1, P < 0.02), meeting the general prediction of cross-sex affiliation as a mechanism for female protection against infanticide, which has been reported in this population.