one of the largest animal collections in the southwestern United States, located in San Antonio, Texas. Founded in 1914, the zoo and accompanying aquarium are operated by the San Antonio Zoological Society and occupy a 35-acre (14-hectare) site with natural springs and rock cliffs. More than 3,500 specimens of approximately 750 terrestrial and aquatic species are bred and exhibited. The zoo's collection of birds (bird) is one of the largest in the world and includes the first Caribbean flamingo colony to breed in captivity and a breeding pair of endangered whooping cranes. Another notable feature is the zoo's African animal exhibit, composed of outdoor enclosures that simulate the natural habitat of the specimens displayed (e.g., the East African Rift Valley and plains).