Behavior and Ecology of the Mona Monkey in the Seasonally Dry Lama Forest, Republic of Bénin

I investigated the behavior and ecology of the mona monkey (Cercopithecus mona Schreber, 1774) in the Lama Forest for 17 months, and estimated the population density and biomass of the anthropoid species in the forest. I found that Cercopithecus mona forms mixed-sex groups and all-male groups. Multiple males in mixed-sex groups interacted amicably, but males belonging to different groups behaved aggressively towards each other during intergroup encounters. Male-male relationships in C. mona appear to differ from those reported in some other arboreal guenons (e.g., C. diana, C. mitis). Fruits and legume seeds and arils were the most important foods for C. mona. Nearly 40% of its food came from Dialium guineense and Diospyros mespiliformis, the most common tree species. During the first major dry season, C. mona fed extensively on nectar and flower parts of Ceiba pentandra, immature seeds of Dialium, and arils of Afzelia africana legume seeds. During the second major dry season, C. mona fed mostly on Afzelia seed arils, mass-fruiting immature seeds of Dialium, and nectar of Ceiba flowers. Immature seeds were eaten when fleshy fruits were scarce. Factors such as low fleshy-fruit diversity, an abundance of Caesalpinioideae trees, and perhaps the superior nutritional quality of seeds and seed arils are all probably responsible for C. mona\u27s choice of the foods that they rely on when few ripe fleshy fruits are available. The population density of C. mona at Lama is one of the highest of all the forests where it has been surveyed. In forests where members of mona species group occurs with few or no other sympatric primates, its biomass is high. In these forests, they thrive with year-round fruits, cultivated foods, or abundant alternative foods such as Caesalpinioideae seeds in seasons of scarcity. In contrast, their biomass is the lowest or second lowest of all arboreal guenons in wetter forests that are dominated by fleshy-fruit producing species, probably because members of the mona species group have a lesser ability to digest leaves and a lower competitive ability than sympatric guenons in territorial conflicts