"Howler Monkey" but as opposed to the Yucatan Black Howler (Alouatta pigra). This one was from Costa Rica. Their predawn howling is pretty impressive and can carry for several kilometers. They also howl in response to rain and other disturbances. It is thought to maintain spacing between separate groups although they don't hold exclusive territories. All howlers look depressed as they sit hunch bakced and have a permanently glum expression.