BRONX, NEW YORK – May 12, 2017 – Six American bison calves have been born at WCS’s (Wildlife Conservation Society) Bronx Zoo and four of them are now on exhibit on the zoo’s Bison Range. The calves will help the Bronx Zoo further bison conservation efforts.


The calves were born to a herd of seven females and one male that arrived at the zoo from Ft. Peck, Montana in November 2016. The herd was an historic gift from the Assiniboine and Sioux tribes and was significant because the Fort Peck bison are from the Yellowstone National Park bloodline, and are among the few pure bison remaining. The vast majority of present-day bison have trace amounts of domestic cattle genes, a reflection of past interbreeding efforts when western ranchers tried to create a hardier breed of cattle. More information about the historic transfer can be found at the WCS Newsroom:  


The female bison were already pregnant when they arrived at the zoo and the calves were born in late April.


“These calves will bolster our efforts to expand our breeding program of pure bison,” said Dr. Pat Thomas, WCS Vice President/General Curator and Associate Director of the Bronx Zoo. “They will eventually be bred with other pure bison to create new breeding herds in other AZA-accredited zoos, and to provide animals for restoration programs in the American West.”


The Bronx Zoo has a long history of facilitating bison conservation projects in the western U.S., and the birth of these calves provides a welcome boost to the zoo’s ongoing efforts to establish a herd of pure bison.


For more than five years, the Bronx Zoo has worked on developing a herd of pure bison through embryo transfer. The bison from Ft. Peck will supplement those efforts. The bull currently on exhibit with the females and calves was the first American bison born as a result of embryo transfer in 2012. More information about the Bronx Zoo’s efforts to breed bison through embryo transfer can be found on the WCS Newsroom:


Bison and WCS

The bison is an American conservation success story. In the early 1900’s, the bison was on the verge of extinction – numbering fewer than 1,100 individuals after roaming North America in the tens of millions only a century earlier. In 1907 and 1913, the Bronx Zoo sent herds of Bronx-bred bison out west to re-establish the species in its native habitat.


WCS is continuing its tradition of using science-based solutions both in the field and in its wildlife parks to maintain viable bison populations and to preserve this icon of American heritage. One goal within this vision is to create and maintain ecologically functional herds of bison.


In April of 2016, WCS and other members of the American Bison Coalition, scores of bison-friendly groups, organizations, and businesses celebrated passage of the National Bison Legacy Act by Congress—making the bison the National Mammal of the United States. President Obama signed the legislation on May 9, 2016.