Red Howler Monkey
- Factsheet on this species from the South American rainforests with a photograph and information on its habits.
- http://www.yptenc.org.uk/docs/factsheets/animal_facts/red_howler.html

Cebidae Family
- Characteristics and detailed species accounts of the New World monkeys.
- http://animaldiversity.ummz.umich.edu/chordata/mammalia/primates/cebidae.html