This particular monkey is an adolescent. It is probably about 15 - 18 months old. It weigh approximately four kilos and is about two feet long without it's tail. Howler Monkey's are herbivores and spend their days and nights in the trees. Only when they have no way to get from one tree to the next (primarily due to deforestation) they go to the ground and move quickly to get to the next tree. In this case, they were using an overhead electrical wire to go from a mango tree to some secondary forest sized trees where they continued to feed. They must move from tree to tree in order to insure they don't become poisoned by eating too much of any one leaf specie. they live in Family groups whereby there is an alfa male that has mating, roosting, and eating rights over all others. Alpha males are in charge of taking the families (averaging 15 in size) through their feeding grounds which are typically one square kilometer/group. Howler Monkey's can live up to 25 years.
Tropical dry forest in NW Guanacaste, Costa Rica. This is four months into the seven month rainy season.