The Saint Louis Zoological Park, commonly known as the Saint Louis Zoo, is in Forest Park in St. Louis, Missouri. It is recognized as a leading zoo in animal management, education, conservation, and research. A special feature is the 2 ft (610 mm) narrow gauge Emerson Zooline Railroad with passenger trains pulled by Chance Rides C.P. Huntington locomotives that encircle the zoo, stopping at the most popular attractions.
By 1910, increased interest in a zoo brought together some concerned citizens, and they organized the Zoological Society of St. Louis. The citizens of St. Louis and surrounding municipalities expressed diverse opinions as to the appropriate location of a zoo if there should be one. Some concerned citizens residing near Oakland Avenue, south of Forest Park, expressed their displeasure with a zoo in the park because of the smell of the animals.
The city purchased its first exhibit, the Flight Cage, from the Smithsonian Institution following the 1904 St. Louis World’s Fair. After the zoo was established in 1910, new exhibits, buildings and areas were added through the decades to improve care of the animals, the range of animals and habitats shown, as well as education and interpretation.
The early years-
The 1904 St. Louis World’s Fair is credited for the birth of the Saint Louis Zoo. This was the first piece of what would become the Saint Louis Zoo.
Emerson Zooline Railroad.
The number of board members was increased to nine in 1916, the same year the citizens voted to create a tax for the construction of the Saint Louis Zoo, with a 1/5 mill tax. It is said that this was the first zoo in the world that the citizens of a community supported by passing a mill tax.
1920 through 1969.
Expansion of the zoo started in 1921 when the Bear Pits were built. The zoo continued to expand with the construction of the Primate House in 1923 and the Reptile House in 1927.
Major construction started on the zoo again in 1961 when the Aquatic House was built. It continued with the opening of the Emerson Zooline Railroad in 1963, the Charles H. Yalem Children’s Zoo, and the animal nursery in 1969. 5]
The Stupp Memorial Pheasantry and the lion arena, now the Sea Lion Arena, were built in 1954. Three years later, the Elephant House and its arena and moated yards were constructed. 5]
The new Bird House was built in 1930. With the coming of the Great Depression, revenues were down and construction of new exhibits slowed at the zoo. In 1939, the zoo acquired two giant pandas.
1970 through Present.
In 1972, the zoo joined the Metropolitan Zoological Park and Museum District and began to receive revenue from a public property tax of 8 cents for every $100 assessed. Two major areas of the zoo, Big Cat Country and Jungle of the Apes, were constructed in 1976 and 1986, respectively.
In 2000, the Monsanto Insectarium, including the Butterfly House, was built. In 2002, the third phase, featuring habitats of South America and Africa, opened with hippos, rhinos, warthogs, carmine bee-eaters, capybaras, and giant anteaters.
Polar Bear Point features a polar bear called Kali. The Fragile Forest and Jungle of the Apes features gorillas, chimpanzees, and orangutans in a naturalized outdoor setting. Penguin and Puffin Coast displays a variety of water birds including Humboldt penguins, Emperor penguins, King penguins, rockhopper, gentoo penguins, horned puffins, tufted puffins, and king eiders.
The following people have served as directors of the zoo: .
Beginning in 2013, the Saint Louis Zoo is undergoing a massive expansion of facilities and space for both visitors and staff. Most notable amongst this is a new development planned on 13.5 acres on the grounds of the former Forest Park Hospital, across Interstate 64 from the zoo campus. Once completed, the new facility will feature classrooms and offices, year-round exhibits, a mixed-use development that will link the complex with the adjacent Dogtown neighborhood, and an “iconic” connection of the two sites over Interstate 64.
Open during the warmer months, Caribbean Cove is a shallow touch-pool underneath a large pavilion that features cownose rays, southern stingrays, bonnethead sharks, and bamboo sharks. It is one of the only parts of the zoo requiring an admission price, but is free during the first hour the zoo is open.
In 1989, the Living World, a two-story building including classrooms, a reference library and teacher resource center, an auditorium, two exhibit halls emphasizing evolution and ecology, a large gift shop, a restaurant, and offices was built. 
In 1993, the zoo received a donation of the 355 acres (1.44 km2) Sears Lehmann farm, located west of St. Louis. 5]
George P. Vierheller (1922– 1962).
R. Marlin Perkins (1962– 1970), who gained fame for the zoo as host of Mutual of Omaha’s Wild Kingdom  William J. Hoff (1970– 1973).
Robert T. Briggs (1973– 1975).
Richard D. Schultz (1975– 1982).
Charles H. Hoessle (1982– 2002).
Dr. Jeffrey P. Bonner (2002– present)  Park Zones.
The South America exhibit displays spectacled bears, bush dogs, capybaras, giant anteaters, and scarlet macaws. The Asia exhibit features adult Asian elephants and sun bears. The North American exhibit displays fish and wildlife from the Missouri and Mississippi Rivers containing crayfish, American bullfrog, channel catfish, bluegill, and gar.
In 1998, new areas were added with the Emerson Children’s Zoo. 5]
The St. Louis Children’s Zoo has many educational features, such as the see-through slide through the otter pool and many birds, snakes, frogs, and other animals that volunteers and staff bring out for the kids to see up close. This is one of the few exhibits at the Zoo that requires an admittance fee; however admission is free for the first hour the zoo is open during the summer. As of March 2016, the zoo has Tasmanian devils in this section.
Knew that year was the Mary Ann Lee Conservation Carousel, featuring unique hand-carved wooden animals representing endangered species at the Saint Louis Zoo. In 2015, the zoo opened Polar Bear Point, a $16 million facility that exhibits and includes different landscapes about the polar bear’s relationship with the Arctic ecosystem. Its first resident is named Kali, an orphaned polar bear donated to the zoo by the U.S. Fish and Wildlife Service.
Most of the zoo’s invertebrates are found in the Monsanto Insectarium. Represented species include leafcutter ant, flower mantis, Vietnamese walking stick, Atlas beetle, American burying beetle, sunburst diving beetle, water scorpion, brown widow spider, brown recluse spider, yellow garden spiders, Platymeris biguttatus, cobalt blue tarantula, Texas brown tarantula, and Egyptian fat tail scorpion.
1904 Flight Cage (Aviary).
Spectacled caymans at the Herpetarium.
The herpetarium houses most of the zoo’s amphibians and reptiles, including the critically endangered Jamaican iguana, Chinese alligator, McCord’s box turtle, Panamanian golden frog, and Arakan forest turtle. The Chain of Lakes is a series of small enclosures between the Bird House and the Herpetarium and Primate House, where the zoo’s North American river otters and alligator snapping turtles reside. Primate House is home to the zoo’s monkeys and lemurs.
The Saint Louis Zoological Park, commonly known as the Saint Louis Zoo, is in Forest Park in St. Louis, Missouri. The 1904 St. Louis World’s Fair is credited for the birth of the Saint Louis Zoo. Knew that year was the Mary Ann Lee Conservation Carousel, featuring unique hand-carved wooden animals representing endangered species at the Saint Louis Zoo. It is one of the only parts of the zoo requiring an admission price, but is free during the first hour the zoo is open. The St. Louis Children’s Zoo has many educational features, such as the see-through slide through the otter pool and many birds, snakes, frogs, and other animals that volunteers and staff bring out for the kids to see up close.
Somali wild ass.
St. Louis Zoo, 2005.
At Antelope House the species present are the addax, babirusa, Banteng, Bactrian camel, gerenuk, Grevy’s zebra, Indian muntjac, lesser kudu, mountain bongo, okapi, reticulated giraffe, Somali wild ass, Speke’s gazelle, Sichuan takin, gorals, Soemmerring’s gazelle, Transcapsian urial, and Visayan warty pig. Non-ungulates found in the Red Rocks include the marsupials red kangaroo and tammar wallaby, as well as several birds in mixed-exhibits with the ungulates, such as the ostrich, Stanley crane, and grey crowned crane.