Antilocapridae introduction

Family Antilocapridae

Antilocapridae (pronghorn; 1 Genus, 1 species) have single living species (Antilocapra americana) and are endemic to North America, and the entire fossil record of this family is restricted to the Nearctic.

Pronghorn live in a temperate and open habitat and are browsers. They have a body weight of ~40 kg, four-chambered stomach, hypsodont teeth, and a gall bladder.

The "horns" of the pronghorn are of special interest. Pronghorns are comprised of a slender, laterally-flattened blade of bone which grows from the frontal bones of the skull, forming a permanent core. As in the Giraffidae, skin covers the bony cores, but in the pronghorn it develops into a keratinous sheath which is shed and regrown on an annual basis. Unlike the horns of the family Bovidae, the horn sheaths of the pronghorn are branched, each sheath possessing a forward pointing tine (hence the name pronghorn). The horns of males are well developed; in females, they are either small, misshapen, or absent.

The modern pronghorn is one of the fastest-running mammals. At full speed, a pronghorn can reach 85-95 kilometers per hour, and can maintain a speed of 65 kilometers per hour over at least 10 kilometers. Their incredible speed is thought to be the result of an evolutionary arms race with the now extinct North American cheetah.


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The Antilocapridae Family Tree