The Feeding Ecology of Yucatan Black Howler Monkeys (Alouatta pigra) in Mangrove Forest, Tabasco, Mexico

Mangroves are composed of relatively few species of plants specially adapted to tidal inundation and saline conditions. Mangrove communities are not considered ideal environments for most mammals, especially large-bodied arboreal herbivores, because of the low-diversity, and supposedly, low-quality vegetation. In this study, I investigate the diet and behavior of a population of Yucatan black howler monkeys (Alouatta pigra) isolated in mangrove forest on the Pantanos de Centla Biosphere Reserve in Tabasco, Mexico. I focused my research on the relationship between the behavioral ecology of the monkeys and the diversity, distribution, and nutritional content of mangrove plants. After observations and plant collection over the wet and dry seasons, I found that the mangrove forest was very low in diversity, dominated by only two tree species (77%), and the howlers' diet consisted of only 12 species of tree and liana, low compared with the average 60 species for the genus. The diet of the mangrove howlers was significantly different than other howlers, incorporating more flowers and seeds and less fruit. Mangrove plants were significantly different in nutrient components, as well. I show that despite the mangrove being a less-than-desirable habitat for these primates, it is sufficient and the howler population there is stable. The implications from my research support the notion of howler monkeys as highly flexible in their habitat usage and behavior and that mangrove forests are a viable option for conservation efforts. Most importantly, I think we must recognize the importance of investigating the phytochemical characteristics of foods in addition to general dietary selection in order to suss out the true influence of diet and selection on biology and behavior.