The pronghorn (Antilocapra americana ) is a native mammal of North America and the last surviving member of family of similar species that existed in North America up until about 12,000 years ago. At that time there were about 12 related species. That number was down to five species by the time humans first arrived in North America.
Looking very much like species of antelope found in Africa and Eurasia, pronghorn are not antelopes, although they are sometimes referred to as such. Like other even-toed hoofed animals, pronghorns chew cud - their own partially digested food. This practice enhances extraction of nutrients from otherwise indigestible cellulose and other fibrous plant material. Pronghorn, like all cud chewers, are herbivores.
As in many herd-forming animals, male pronghorn will form harems of females that they will defend against other males to insure exclusive access to these females. This defense results in aggressive encounters between males that can include physical combat, like that being displayed by the two young males seen in this week's photo. These battles over females can result in physical injuries to the combatants. By engaging in the "play fighting" as juveniles, they learn and perfect techniques that they will use as adults.
Pronghorn are also noteworthy for their maximum running speed, clocked at nearly 60 miles per hour. This makes them among the fastest of land mammals in North America, and gives them the ability to outrun predators like coyotes and bobcats. Besides high maximum running speeds, pronghorn also are superb endurance runners, being able to run for miles at about half their maximum speed. Using this ability, pronghorn undertake an annual 300-mile round trip migration. This distance is second only to caribou among migrating North American land animals.
This week's photograph was taken in Bryce Canyon National Park in Utah in the United States of America. It was taken using a Canon 5D MkIII dSLR and an EF 100-400 mm lens zoomed to 350 mm. Exposure was set at a shutter speed of 1/250 sec at f/5.6 and an ISO of 3200.