July 2, 2013

Defenders of Wildlife has set itself the goal of moving more than 100 endangered species up the federal recovery ladder over the next decade. Our “Road to Recovery” series will highlight several of these plants and animals and outline the challenges that lay ahead for improving their status.

Dire Straits in Desert Southwest

What has horns, can travel at highway speeds and almost disappeared forever ten years ago? No, it’s not a truck full of bulls rescued from the slaughterhouse. It’s the Sonoran pronghorn, the fastest land mammal in North America, capable of sprinting up to 60 miles per hour over short distances.

Sonoran pronghorn NPS wm

Sonoran pronghorn are the fastest land mammals in North America.

Sonoran pronghorn are an exceptionally rare subspecies of pronghorn found in the Sonoran desert of southwestern Arizona and northwestern Mexico. These deer-like animals are slightly smaller and lighter than their cousins, the American pronghorn, which exist across much of the interior western United States from Montana down to Texas.

Because they inhabit one of the driest regions on the continent, Sonoran pronghorn have adapted to going long periods without water. They survive by eating the most succulent parts of desert shrubs, forbs, trees,   and certain cacti.. Their four-part stomach helps them digest these hardy greens, while their fast feet, keen eyesight and innate wariness keep them out of the jaws of hungry predators.

For millennia, pronghorn survived by living on the move. They roamed widely across the desert in search of food and water, often traveling hundreds of miles between meals. But the expansion of human developments in the Southwest has made their nomadic lifestyle nearly impossible. As a result of a host of stressors, including prolonged drought conditions, their precarious population quickly plummeted.

The species was officially protected under the precursor to the Endangered Species Act in 1967, but it continued to dwindle as a result of habitat loss and fragmentation, human disturbance and competition for forage with grazing cattle. Then in 2002, after one of the hottest and driest years on record, Sonoran pronghorn came about as close to extinction as a species can get without actually blinking out. All but 21 pronghorn in the U.S. perished as a result of a severe 13-month drought.

In 2004, biologists stepped in to rescue the drought-stricken pronghorn by creating a captive breeding program at Cabeza Prieta National Wildlife Refuge, just north of the Mexican border. Supplemented with pronghorn from larger Mexican subpopulations, the breeding program proved to be successful. Since 2006, captive-bred animals have been released into the wild across several different sites, including Barry M. Goldwater National Wildlife Refuge, Organ Pipe Cactus National Monument and Kofa National Wildlife Refuge.

Supplemental feeding at captive breeding facilities has helped pronghorn survive drought and increase their numbers.

Supplemental feeding at captive breeding facilities has helped pronghorn survive drought and increase their numbers.

The most recent reintroduction project included creating a captive release facility in the King Valley area of the Kofa National Wildlife Refuge, where pronghorn hadn’t been in more than 100 years. Ten pronghorn were relocated there earlier this year, and eight of them were set to be released into the wild to create a new population that will not only expand this endangered pronghorn’s range, but hopefully boost its population numbers as well.

Because of these captive breeding programs and collaborative conservation efforts between state and federal agencies, Sonoran pronghorn are now recovering from near-extinction to healthier levels. About 100 pronghorn currently survive north of the border and an estimated 600 still exist in Mexico.

Sonoran pronghorn still face unrelenting drought conditions, which scientists predict will only become more extreme as climate change fuels increasing temperatures and decreased precipitation.

But their numbers are finally moving in the right direction. With continued efforts by state, federal and military land managers, Sonoran pronghorn could someday become one of the great American wildlife conservation success stories.

Watch the video below to learn more about Arizona Fish and Game’s efforts to restore wild pronghorn:

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