zoo in Baltimore, Md., that is the third oldest zoo in the United States (after the zoos in Cincinnati (Cincinnati Zoo and Botanical Garden), Ohio, and Philadelphia (Philadelphia Zoological Gardens), Pa., respectively). The site contains more than 1,500 mammals, birds, reptiles, and amphibians, encompassing nearly 200 species on more than 160 acres (65 hectares) of city land.

Druid Hill Park, the site of the Maryland Zoo, became an unofficial zoo in 1862, when local citizens donated four swans to the park for public display. As donations of animals continued, the zoo was brought into being by an act of the state legislature in 1876. The Maryland Zoological Society has managed the zoo since 1984 under a lease agreement with the state. In 2004 the zoo officially changed its name, renovated the park, and modernized its facilities.

The zoo's Polar Bear Watch features a transparent viewing pool and a tundra safari ride. There are camel rides, and a popular children's park includes farm animals. The warthog exhibit is the only one in the country that dedicates an entire enclosure to these African animals. Other exhibits include the Chimpanzee Forest, the Leopard Lair, the African Watering Hole, and a section dedicated to the wildlife of Maryland.