William T. Hornaday (1854–1937), a zoologist and a pioneer in wildlife conservation, helped found the National Zoo in Washington, D.C., and was the founder and then director of the New York Zoological Park for more than 20 years. Hornaday is generally credited with saving the American bison and other wildlife species from extinction.
Knowing that bison were becoming scare, in 1886 Hornaday went to Montana to collect specimens of plains bison for the National Museum in Washington, D.C. Although the region had supported tens of thousands of bison just decades before, he was able to collect only 25 bison in the eight-week-long endeavor. He returned convinced that the species was in danger of imminent extinction. By 1893, fewer than 1,000 bison were left of the massive herds that by conservative estimates in the 1500s, prior to the arrival of Europeans, had numbered between 30 and 60 million animals.
Hornaday served as president, with Theodore Roosevelt as honorary president, of the American Bison Society founded December 8, 1905, by a group of sportsmen and dedicated conservationists. Roosevelt persuaded Congress to establish a number of wildlife preserves, and with the help the Society solicited assistance from private bison owners to stock them with animals. A 1929 inventory of bison now counted 3,385 total animals, encouraging enough that the Society continued its programs and activities.
Ranchers and breeders recognizing the obvious economic potential of the animal expanded their efforts to preserve, protect and reestablish the American Bison. Today the number of bison in North America (U.S. and Canada combined) has risen to nearly 500,000 head under commercial management. Approximately another 30,000 head—19,000 plains bison in 54 conservation herds, 11,000 woods bison in 11 conservation herds—are managed by various government agencies.