History of Zoology: A brief overview of zoological practices from 4500 B.C. to the 20th century.The History of Zoos: A brief overview offered by Zoo Check, an anti captivity project of the Born Free Foundation.Zoo and Aquarium History: The Bartlett Society offers historical articles discussing the Tower Menagerie, the Cincinatti Zoo, the Philadelphia Zoo, and the Washington Park Zoo.Zoos: A Historical Perspective: Online exhibition by the National Zoological Park Library, Smithsonian Institution.