WILD THING

Made to Move

Speedy pronghorn face challenges they can’t outrun.

by Paula Levihn-Coon

Pronghorn, named for the prongs on their horns, are neither antelope nor goats despite their Latin name, Antilocapra americana, which means American antelope-goat. They are the only living North American animal in the Antilocapridae family; their relatives are all extinct.

When Europeans arrived in North America, 30 million pronghorn lived here, moving with bison across the treeless grasslands of the Great Plains.

Starting in the 1880s, however, settlers slaughtered pronghorn — unchecked — for food and hides, and altered the habitat through farming, urbanization and fencing, which reduced the population to about 13,000 across the continent. After states enacted hunting restrictions and management actions, the population rebounded to 1.1 million by the 1980s.

Pronghorn are North America’s fastest land animal, capable of 30-foot strides at 60 mph and maintaining 35 mph for long distances. In Texas, pronghorn live in the Trans-Pecos and the Panhandle, with a small population near San Angelo.

“Everything about them is made to move — their bone structure, their muscle groupings, even all the bones and vessels in their noses,” says Tony Opatz, a New Mexico Department of Game and Fish biologist who recently completed his master’s thesis studying pronghorn movements and habitat use in the Texas Panhandle through Texas A&M University-Kingsville, with funding from the Texas Parks and Wildlife Department.

Female pronghorn are baby factories. More than 90 percent of does produce fawns, and more than 95 percent of these births result in twins, when nutrition is adequate.

“If pronghorn didn’t have twins, we probably wouldn’t have pronghorn,” Opatz says. “It’s a huge evolutionary ‘one-up’ for them.”

Fawns are up and running in about a week, but TPWD biologists count only about 30 fawns per 100 does during summer aerial surveys. Poor habitat quality and predation are two of the leading causes of fawn deaths.

Impacts from the 2011 drought caused the Trans-Pecos population to crash, from more than 7,000 in 2007 to fewer than 2,500 in 2012. In a public-private effort from 2011 to 2018, landowners, TPWD, the Borderlands Research Institute at Sul Ross State University and other partners translocated 750 pronghorn (mostly pregnant does) to the Trans-Pecos from the Panhandle, which had an ample population.

The survival rate for translocated animals one year after release was only 20 percent in 2011, primarily because of the drought. However, with improved protocols and range conditions, survivorship is now around 70 percent.

“Pronghorn are probably the most difficult big game species to capture and translocate with minimal loss,” says Shawn Gray, TPWD mule deer and pronghorn program leader. “The way they avoid predators using their speed, their desire to herd together and nervous nature are challenging, but with the right folks and protocols, pronghorn capture and translocation can be done safely and effectively.”

Biologists determined that severe malnutrition from drought caused soaring fawn death rates and made pronghorn susceptible to infestations of massive numbers of blood-sucking barber pole worms. Another challenge in today’s times: Pronghorn dislike jumping fences and thus can’t chase rain events to better pasture if fences do not allow pronghorn to pass underneath.

To help pronghorn survive, teams of biologists, students and volunteers — with landowner permission and cooperation — have been modifying fences so pronghorn can crawl under them. So far, they’ve done about 2,000 “fence mods” across the Trans-Pecos.

The Texas pronghorn population now stands at 20,000 but is again on the decline due to the current drought. Allies of this iconic American species continue to be on the watch to ensure their existence and population growth.