It was the first true zoo in the United States; it was chartered by the Commonwealth of Pennsylvania on March 21, 1859, but its opening was delayed by the Civil War until July 1, 1874.

Special features include a children's petting zoo, a rainforest themed carousel, a climbing structure, chats with keepers, behind the scenes tours available for purchase, and many interactive and educational exhibits.

[8][9][10] When the Philadelphia Zoological Garden first opened its Victorian gates on July 1, 1874, to over 3,000 visitors, it was the only institution of its kind in the New World.

The zoo began with varied exhibits containing 200 mammals, including buffalo, deer, wolves, foxes, bears, and monkeys, and 67 bird species and 15 reptiles.

Since 2013, zoo officials have been working to get the station restored and reopened, to potentially increase attendance and alleviate parking issues on their busiest days.

Philadelphia Zoo also pioneered the first captive management of flamingos under the direction of curator emeritus John A. Griswold.

[16] The rescue plan called for the capture of all kingfishers and rails on Guam, along with the development of a captive management program.

Zoo360 is a network of see-through mesh trails, consisting of elevated and ground-level structures, along which animals can explore the zoo away from their enclosures.

Subsequent additions to the system include the Great Ape Trail, Big Cat Crossing, Gorilla Treeway, and Meerkat Maze.

KidZooU is notable for many ecologically conscious features, such as rain gardens and cisterns, geothermal wells, and green roofs, making it the first LEED-certified exhibit at the zoo.

[23] On December 29, 2016, Zenda, the oldest African lion in the U.S. zoo population, was euthanized following a sudden loss of appetite and failing health.

[24] On February 20, 2018, Coldilocks, a 37-year-old polar bear was euthanized after declining health including potential liver and spinal problems.

[27] During the Holiday Season (Late November to Early January), the Philadelphia Zoo hosts a walking nighttime light show called Luminature.

The experience also includes actors dressed as illuminated animals and the chance to sit in a fire pit area and make s'mores.