Essays

Wild On The Prairie: Mammals

Pronghorn
April 11, 2011

If I described an animal species thusly; “Unique to North American grasslands, the only animal in the world with horn sheaths, can run over two miles at 45 miles an hour, has a huge heart and lungs and high counts of hemoglobin, incredible eyesight, hair like velcro, and are amazingly curious,” what would be your answer? You might say “antelope,” but it is not. It is properly known as the pronghorn.

A number of years ago I was helping a rancher do some riparian restoration. Early one morning, I took a walk, before it had really become light. I'd walked maybe 400 yards in the moonlight when the rancher's big Chow (who was walking with me) froze. I could feel his every muscle tighten, even though he was six inches away from me. I looked in the direction he did, and three pronghorn just a few feet away. We had caught them sleeping.

The pronghorn peered at us from their comfortable prone positions. Pronghorns acting like satisfied cows! Dad-gum, it was different. I slowly sank to the ground, and sat down Indian-style. That dog was smart. He hunkered down, too -- no growling -- just an intent look. I think the pronghorn were puzzled -- what was that wild fierce canid doing with a biped? That just didn't compute in their minds. They were staring at Segundo, just boring holes in him with their stare.

I have heard that predators and prey have a language of death. Supposedly they signal each other in very subtle ways about their present physical condition. I wonder if Segundo's actions told them not to worry? I figured they would get up and go sprinting away – they run 60 to 70 miles an hour in short bursts, so I knew Segundo couldn't catch them. But they just kept sitting there, and we kept sitting there.

Probably five minutes passed, and it got a little lighter. Instead of only seeing their forms among the yuccas, I began to see detail on their faces. As it became even lighter, I could sense a growing nervousness. So could Segundo. His muscles tensed and he began to quiver. I couldn't take it anymore and I stood up, waving my arms, and hollering. Segundo jumped the very second I propelled myself up. I swear they went from a kneeling position to full-out pedal-to-the-metal scratch-laying and tire-squealing.

It is amazing how few kids know what a pronghorn is...they see the head mount at Sibley and call it a deer or a reindeer. Any weekend a person drives to Ruidoso for some fun at the horseraces or skiing or hiking in the cool mountains, a half dozen herds will appear between Bronco and the highway junction east of the Capitan Mountains.

The pronghorn is not a true antelope, but rather is the sole remnant member of an American family of mammals from the Miocene and Pliocene times. The pronghorn is America’s swiftest mammal; sometimes reaching speeds over 40 mph. Pronghorns have a highly developed sense of curiosity, examining at close range, any unrecognized object, particularly one that moves. A peculiarity of the pronghorn is its hollow horns that grow over a bony core. Every fall the horns are shed and new ones grow over the core. The male’s horns are much larger than those of the female are, and some females have none. The pronghorn is physiologically adapted to arid conditions. It can go for long periods without drinking water by conserving body water and extracting water from its food.

In 1946 Texas Parks and Wildlife released 44 pronghorn (12 bucks, 32 does) in Midland County. The majority of the pronghorn population resides within the block of land bordered by Interstate 20 on the north, SH 349 on the east, FM 1787 on the south, and FM 1788 on the west. Several herds of 30 to 40 in Midland County were found in the area. Now only 40 or so animals remain. These pronghorn face several challenges to population recovery. Pronghorn usually will not cross net wire fences, which reduces accessible rangeland and natural movements. Pronghorn also prefer open prairies and tend to avoid areas of heavy brush. Pronghorn in the Tran-Pecos have declined from around 10,000 in 2007, to 6,700 in 2008, to around 4,700 in 2010. A parasite, the barberpole worm (Haemonchus spp.), seems to be driving the current decline. It is not known if the local herd is affected by these worms. Because of the current decline in the Midland County herd, TPWD is planning a free educational workshop and looking for landowners interested in forming a management cooperative to benefit the pronghorn.