Protecting the nearly extinct Sonoran pronghorn in Arizona is making it more difficult to prevent illegal immigrants from entering the U.S., at least according to Fox News.

"Environmentalists and governmental stewards have been repeatedly blocking customs and border protection from expanding border technology in their habitat—despite complaints that illegal immigrants are taking advantage of the security gap and doing plenty of harm to the environment in the process," wrote Judson Berger of Fox News.

Sonoran pronghorn (Antilocapra americana sonoriensis)—a subspecies of the more well-known pronghorn—have been protected under the Endangered Species Act since 1967, but that didn't prevent them from almost going extinct in this century. In 2003, following several dry years, the population crashed to just 21 animals. It recovered quickly, rebounding to about 100 by 2006, the same year the U.S. Fish and Wildlife Service (FWS) released the first captive-bred Sonoran pronghorn into the Arizona wild. That didn't last though: by June 2009, the wild population was back down to around 70 animals, according to a report earlier this year from The Arizona Republic.

In addition to the wild Sonoran pronghorn in Arizona, FWS maintains a captive breeding population of about 70 animals, and two additional herds live in Mexico. Some of the Mexican animals were brought to the U.S. for the FWS's breeding program, although transporting the pronghorn was not without difficulty: Many of imported animals died (pdf) from "capture myopathy," caused by the buildup of lactic acid in overexerted and overstressed creatures.

To bolster its ability to monitor the border, the U.S. Department of Homeland Security (DHS) is currently building one communications tower—out of an originally proposed seven—in the Sonoran pronghorn's habitat. The FWS blocked the construction of the other six because of their potential impact on the endangered animals, according to Fox News.

George Nickas, director of Wilderness Watch in Missoula, Mont., told Fox News that all of the activity from building and then staffing communications stations in the area would harm the environment, and the pronghorn in the process. As the Arizona Republic article points out, the Sonoran pronghorn habitat currently has no fences or roads, which the animals do not like to cross—and which DHS would likely need to build in order to construct and staff its facilities. The FWS identifies some of the major threats to pronghorn as fences ("pronghorn don't jump," the agency says), loss of habitat and vehicle collisions.

Pronghorn look like a cross between antelopes and goats but are actually neither. Their closest living relatives are, strangely enough, giraffes, but all other members of their taxonomic family are extinct. The Sonoran pronghorn is the fastest land mammal in North America, with top racing speeds of more than 95 kilometers per hour.

Photo: Pronghorn (Antilocapra americana) via Wikipedia