In 1895, a group made up largely of members of the Boone and Crockett Club founded the New York Zoological Society (later renamed the Wildlife Conservation Society) for the purposes of founding a zoo, promoting the study of zoology, and preserving wildlife.[9] Credit for this belonged chiefly to Club members Madison Grant and C. Grant LaFarge.[10]

The zoo (sometimes called the Bronx Zoological Park[11] and the Bronx Zoological Gardens[12]) opened its doors to the public on November 8, 1899, featuring 843 animals in 22 exhibits. Its first director was William Temple Hornaday, who had 30 years of service at the zoo.[13]

Heins & LaFarge designed the original permanent buildings, known as Astor Court, as a series of Beaux-Arts pavilions grouped around the large circular sea lion pool.[6] In 1934, the Rainey Memorial Gates, designed by sculptor Paul Manship, were dedicated as a memorial to noted big game hunter Paul James Rainey.[14] The gates were listed on the National Register of Historic Places in 1972.[7]

The Rockefeller Fountain, which today adorns the gardens just inside the Fordham Road Gate, was once a landmark in Como, Italy. Originally built by Biagio Catella in 1872, it stood in the main square (Piazza Cavour) by the lakeside.[15] Bought by William Rockefeller in 1902 for 3,500 lire (the estimated equivalent then of $637, and today of around $17,600), it was installed at the zoo in 1903. In 1968, the fountain was designated an official New York City landmark, and is one of the few local monuments to be honored in this way.[16]

The New York Zoological Society's seal was designed by famed wildlife-artist Charles R. Knight. It depicted a ram's head and an eagle to reflect the society's interest in preserving North American wildlife.[17] While no longer in use, the seal can still be found on the lawn in the center of Astor Court.

On December 17, 1902, the zoo became one of the seven zoos outside of Australia, and one of only two in the United States, to ever hold the now-extinct thylacine. The first was a male obtained from German animal dealer Carl Hagenbeck. It died on August 15, 1908. The zoo received a second male on January 26, 1912, from the Beaumaris Zoo in Tasmania, who later died on November 20 of that year. The zoo received its final two animals from Sydney animal dealer Ellis S. Joseph. The first was an unsexed individual who arrived on November 7, 1916, in poor condition and died seven days later. The second and final animal was a female purchased from the Beaumaris Zoo by Joseph for £25 (~$35) and then was resold to the zoo, arriving on July 14, 1917.[18] On a visit, the director of the Melbourne Zoo, Mr. Le Souef, said upon seeing the animal:

I advise you to take excellent care of that specimen; for when it is gone, you never will get another. The species soon will be extinct.

The thylacine died on September 13, 1919.[18]

In early 1903, the zoo was gifted a pair of Barbary lions, a subspecies which is extinct in the wild. The female was named Bedouin Maid and male Sultan, who went on to become one of the zoo's most popular animals. Displayed in the Lion House, Sultan was four years old at the time and described as being both "a perfect specimen" and "unusually good tempered". In May 1903, the pair produced three cubs, the first to be born at the zoo. On October 7, 1905, Charles R. Knight painted a portrait of Sultan and the animal went on to be the focus of many of the zoo's postcards. Sultan was also the model for the lion which sits atop the Rainey Memorial Gates.[19]

In 1916, the zoo built the world's first animal hospital located at a zoo.[5]

In 1926, the Bronx and the Smithsonian National Zoo simultaneously became the first in the country to exhibit shoebills.[20]

The same year, W. Douglas Burden, F. J. Defosse, and Emmett Reid Dunn collected two live adult Komodo dragons—the first in America—for the zoo.[21]

In 1937, the zoo became the first in North America to exhibit okapi." (WIKI)

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"The Wildlife Conservation Society was originally chartered by the state of New York on April 26, 1895. Then known as the New York Zoological Society, the organization embraced a mandate to advance wildlife conservation, promote the study of zoology, and create a first-class zoological park. Its name was changed to the Wildlife Conservation Society in 1993. Among the founders of WCS were Andrew H. Green, best known as the father of greater New York City, Henry Fairfield Osborn, Columbia University professor and curator of the American Museum of Natural History, and George Bird Grinnell, founder of the Audubon Society and editor of Forest and Stream Magazine. Theodore Roosevelt, Madison Grant, members of the Boone and Crockett Club, and other notable New Yorkers were also involved in the Society's creation.