Located in Buffalo, New York is the third oldest zoo in the United States. Each year, the Buffalo Zoo welcomes approximately 400,000 visitors and is the second largest tourist attraction in Western New York, second only to Niagara Falls. Located on 23.5 acres (9.5 ha) of Buffalo's Delaware Park, the Zoo exhibits a diverse collection of wild and exotic animals, and more than 320 different species of plants. Open year-round, the Zoo serves as a source of conservation, education and recreation for Western New York.

The Zoo traces its history to the mid-19th century when Jacob E. Bergtold, a Buffalo furrier, presented a pair of deer to the city of Buffalo. To provide the deer with room to graze, Elam R. Jewett, the publisher of the Buffalo Daily Journal, offered to house the deer on his estate. Simultaneously, plans were being made for the municipal North Park (today's Delaware Park), and Mayor William F. Rogers hired landscape architect Frederick Law Olmsted to include a zoo as part of the park's design. Five years after the deer were donated, more animals were added to the collection, and the first permanent building was erected, signifying the establishment of the Buffalo Zoological Gardens in 1875.

The Zoo underwent a large expansion during the Great Depression and became a major work site for the Works Progress Administration. Throughout the next several decades, more exhibits and facilities were added, including the Reptile House (1942), Children's Zoo (1965), Giraffe House and Veterinary Hospital (1967), and The Gorilla Habitat Building (1981). The Zoo's mission also began to change during the 1980s and 1990s under the direction of Minot Ortolani, as it began reducing the numbers of animals in its collection to focus on the breeding of endangered species that might not otherwise have a chance at survival. In addition to its conservation efforts, the Zoo also placed more of an emphasis on education to teach visitors about the animals and their natural habitats.

In 2002, a 15-year Master Plan was unveiled to transform the Zoo. New visitor amenities and naturalistic habitats were planned, including the Asian River and Highlands Zone, African Watering Hole, Arctic Edge and the Wonders of Water Children's Zoo. Phase One of the Master Plan has resulted in the opening of the Vanishing Animals exhibit, EcoStation, Otter Creek and Sea Lion Cove. The completion of Phase One was marked by the September 10, 2008 opening of the South American Rainforest, a four-season attraction that features a two-story waterfall, dozens of colorful free-flighted birds and a variety of other rainforest species. These include Ocelots, Blue Poision Dart Frogs, and many other animals you can find in the rain forest.

On November 20, 2007, the organization People for the Ethical Treatment of Animals (PETA) published a press release calling on the Association of Zoos and Aquariums to revoke its accreditation of the Buffalo Zoo based on U.S. Department of Agriculture (USDA) reports alleging unsafe animal conditions and nonstandard handling procedures. Although it is normal for animals to die in captivity, the report alleged that these deaths could have been prevented given adequate facilities and training. The zoo denied such claims, calling PETA an extremist organization. Following an extensive investigation by the USDA's Investigative and Enforcement Services, the Buffalo Zoo was cleared of any wrongdoing regarding its polar bear husbandry or management.