Observational analysis of male-immature interaction of the Mantled Howler Monkey (Alouatta palliata)
Mentor:LeAndra Luecke, Professor of Anthropology, Washington University in St. Louis
Most primate species exhibit little to no male parental care and often the males show aggression toward the immatures. Howler monkeys have been observed to show very little intragroup aggression in comparison with many other species which are multi-male, multi-female groups. Due to the docile nature of howler monkeys in general, we hypothesized that adult males would be more tolerant towards infants and juveniles and possibly engage in association with them. The mantled howler monkey (Alouatta palliata) was used as the focal howler species in the study that was conducted over a three-week period in northeastern Costa Rica. We found that males associated with infants at a rate of 42 times per hour. On average, males associated much less with juveniles. The average rate of associations per hour for juveniles was 43; however, most of these associations were within the same tree and not seen in many other close associations. We conclude that males associate with infants more due to their proximity to females and do not associate commonly with juveniles due to their lack of proximity to females. Our results were consistent with the hypothesis, adult males were tolerant of both infants and juveniles and out of 890 minutes of observations we only observed two cases of aggression. For further research, it would be useful to determine the gender of the infants and the juveniles to conclude if adult males associate more closely with male or female immatures.