Spanning 55 acres at Hermann Park, the zoo is home to 5,000 animals of 700 species. The Wortham World of Primates is a 2.2-acre rain-forest habitat for apes and monkeys. The Tropical Bird House is a walk-through jungle aviary for more than 200 free-flying birds. Other denizens include Siberian tigers, pygmy hippos, giraffes, sea lions and vampire bats.