Houston Zoo, a fifty-five-acre zoological park in Hermann Park, grew from Houston’s earlier small public zoo in Sam Houston Park into one of the nation’s busiest zoos. The present institution opened in 1922 after the arrival of a bison named Earl helped spur development of animal collections and facilities. Its early design followed a 1923 Hare and Hare plan, while its attractions long reflected a menagerie era of performances and cramped barred cages. Over time, the zoo expanded, professionalized, and strengthened its conservation role through accreditation, veterinary and curatorial leadership, species-protection work, and projects in Texas and around the world.