Conserving the Nature of America

News Release

First Captive-bred Sonoran Pronghorn Released

November 29, 2006


Division of Public Affairs
External Affairs
Telephone: 703-358-2220

The U.S. Fish and Wildlife Service has released the first ever captive-bred endangered Sonoran pronghorn into its historic Arizona habitat. Two yearling males, who were born into captivity last year on the Cabeza Prieta National Wildlife Refuge in southwestern Arizona, were released to join other wild pronghorn on the refuge.

Based upon a recommendation by the Sonoran Pronghorn Recovery Team, the refuge and its partners developed a 640-acre, semi-captive breeding facility in 2003 to boost recovery for the endangered pronghorn. The facility is fenced to contain the pronghorn while keeping out predators, and is irrigated to provide for drinking water and plant growth. Refuge and Arizona Game and Fish Department staff captured Sonoran pronghorn in Mexico and on the refuge to stock the semi-captive breeding facility. Nine animals were born in the enclosure this spring. Their contact with humans during captivity has been kept minimal to ensure they remain as wild as possible.

The United States population of Sonoran pronghorn was nearly lost in 2003 plunging to an estimated 21 animals following a series of unusually dry years in which few fawns were born and fewer survived. The wild U.S. population is estimated to be 100.

The pronghorn is the fastest mammal in North America , capable of running up to 60 miles per hour. The continuing recovery of the Sonoran pronghorn is the result of successful cooperative conservation management by an international team of federal, state, and Mexican agencies, organizations and volunteers.

Cabeza Prieta National Wildlife Refuge was established in 1939 to help protect dwindling populations of desert bighorn sheep. Today refuge management focuses on the Sonoran Desert ecosystem and its wildlife.

Service Regional Director Benjamin N. Tuggle, Ph.D. said he was pleased with the success this weekend. "The staff and our partners have done a remarkable job in helping to recover the species," said Tuggle. "We have a way to go to get to sustainable levels but this is a day and a deed for which the Service and our partners can be proud."

The interagency and cooperative effort has been underway for many years and the breeding program since 2002. Continuing efforts are necessary to further recover the animal to fully sustainable levels and will involve ongoing breeding programs and releases, including returning pronghorn to Sonora, Mexico. Throughout the captive breeding program, habitat improvements, predator exclusion and careful monitoring have proven successful strategies to nourish and protect the pronghorn.

"This release from the captive breeding enclosure marks an historic moment in the recovery of this important cross-border species," said Larry Voyles, Regional Supervisor for the southwestern Region (Region IV) of the Arizona Game and Fish Department. "With this release, we move one step closer to restoring a free-roaming U.S. population."

Cabeza Prieta National Wildlife Refuge wildlife biologist and Sonoran Pronghorn Recovery Team Coordinator Michael Coffeen and biologists with the Arizona Game and Fish Department are excited with the prospects for success in the recovery effort. "This is a highly significant action toward the continuing welfare of the species," said Coffeen.

More Facts About the Sonoran Pronghorn

The Sonoran pronghorn is one of five subspecies in western North America. Pronghorn inhabit grasslands, brushlands and open plains and deserts from Canada to Mexico.

Since 1967, the Sonoran pronghorn has been in danger of extinction throughout all or a part of its range. Besides the southwestern Arizona animals, only two other populations exist, in Sonora , Mexico . At this time, an estimated 100 Sonoran pronghorn survive in the wild in theUnited States.

Following a severe drought in 2003, the entire U.S. Sonoran pronghorn population sank to an estimated 21 animals. Since that time, an interagency captive breeding program was established, and 25 animals are currently in captivity.

The pronghorns scientific name Antilocapra americana sonoriensis means "American antelope goat," though the pronghorn is neither antelope nor goat.

Thousands of pronghorn once roamed the open deserts of the southwest until market hunting, livestock grazing, drought and habitat fragmentation by fencing, railroads, highways and water diversion projects caused severe reductions in numbers.

Because pronghorn evolved in open terrain, they rely on their keen eyesight and blazing speed as defensive mechanisms. They never learned to jump over even low barriers. They are averse to crossing railroad tracks, fences, and the other vertical obstacles which dissects their habitat.

Racing at speeds up to 60 miles per hour, pronghorn are the fastest land mammal in the western hemisphere, and in the open, can outrun any predator.

Pronghorn are the only animal to shed their horns (not antlers) each year.

Pronghorn have a deer-like body and weigh between 90 and 125 pounds.

Pronghorn are about 3 to 3-1/2 feet tall at the shoulder.

With large, protruding eyes and excellent vision, pronghorn have a 320 degree field of vision and can see for up to four miles.

Pronghorn are extremely sensitive animals that can be active day or night, alternately sleeping and vigilantly feeding on grasses, herbs, forbs, shrubs and trees.

Female pronghorn in their second year give birth to one or two fawns from February through May. The young weigh from four to twelve pounds at birth, and are about 15 inches tall. The new young can run at a speed of 25 miles per hour after a day or two.


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