Ernie Janes / Black howler (Alouatta caraya) male and female, captive, occurs in Brazil and Paraguay. With digitally added leaf pattern.

Bernard Castelein / Bolivian red howler (Alouatta sara), Pampas del Yacuma Protected Area, Bolivia

Suzi Eszterhas / Colombian red howler monkey (Alouatta seniculus) mother and baby in tree. Northern Colombia.

Ernie Janes / Black howler (Alouatta caraya) captive, occurs in South America.

Thomas Marent / Black Howler Monkey (Alouatta caraya) female, native to South America

Thomas Marent / Black Howler Monkey (Alouatta caraya) female, native to South America

Kevin Schafer / Guatemalan Black Howler Monkey (Alouatta pigra) calling, Community Baboon Sanctuary, Belize, Central America. Endangered species.

Kevin Schafer / Guatemalan Black Howler Monkey (Alouatta pigra) climbing, Community Baboon Sanctuary, Belize, Central America. Endangered species.

Ammonite / Juvenile Mantled howler monkey (Alouatta palliata) climbing through canopy, showing use of prehensile tail, Santa Rosa National Park, Costa Rica.

Ammonite / Mantled howler monkey (Alouatta palliata) climbing through canopy, showing use of prehensile tail, Santa Rosa National Park, Costa Rica.

Juan Carlos Munoz / Black howler monkeys (Alouatta caraya) male and two females calling from tree, captive, Apenheul Park, Netherlands.

Cyril Ruoso / Black Howler Monkey (Alouatta caraya) female resting in tree, native to South America