1. Goodall, J. (1990). Through a Window: My Thirty Years with the Chimpanzees of Gombe, Houghton Mifflin.
2. Fossey, D. (1983). Gorillas in the Mist, Houghton Mifflin.
3. Orangutans, Indonesia’s “People of the Forest”;Natl. Geogr. Mag.,1975
4. Grandin, T. (2008). Humane Livestock Handling: Understanding Livestock Behavior and Building Facilities for Healthier Animals, Storey Publishing LLC.
5. (2024, April 10). Available online: https://www.liverpool.ac.uk/mammalian-behaviour-and-evolution/team/jane-hurst/.