- Why Why Why? Do Orang-utans Live in Trees? (Why Why Why? Q and A Encyclopedia) by De La Bedoyere,  2005-06-01
 - The Orangutan (Remarkable Animals Series) by Ruth Ashby,  1996-03
 - The Malay Archipelago: The Land of the Orang-Utan, and the Bird of Paradise. a Narrative of Travel, with Studies of Man and Nature by Alfred Russel Wallace,  2010-03-29
 - Orangutans (Monkeys) by Mae Woods,  1998-12
 - Orangutans:Wizards of the Rain Forest by Anne E. Russon,  2000
 - Orangutans (In the Wild) by Patricia Kendell,  2003-03-13
 - Problemloseverhalten von Orang-Utans (Pongo pygmaeus) (Fortschritte der Verhaltensforschung) (German Edition) by Jurgen Lethmate,  1977
 - The Natural History of Orang-utan by E.L. Bennett,  1998-12
 - Orangutans (The Untamed World) by Patricia Miller-Schroeder,  2003-12
 - Beitrage Zur Anatomie Der Weiblichen Urogenitalorgane Des Orang-Utan (1898) (German Edition) by Eugen Fischer,  2010-09-10
 - Orangutans Up Close (Zoom in on Animals!) by Carmen Bredeson,  2008-09-01
 - Stop That Orangutan! (Zoey & Me) by Mallory Tarcher,  1998
 - Project Orangutan (Zoo Life) by Susan Ring,  2002-08
 - Orang-utan Biology 
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