Pronghorns (often incorrectly called antelope or pronghorn antelope, to be technical) form huge herds in the alfalfa fields near our home (Modoc County CA) during the winter. It is not unusual to see several hundred pronghorns (Antilocapra americanna) together. Leonard and I love to watch the pronghorns as they graze.
Pronghorns belong to the “Antilocapridae” family. Antilocaprida means “antelope-goat” but pronghorns are neither goats nor antelope. They are a unique species with no close relatives anywhere on earth. And pronghorns definitely are not related to the African antelope. They are the sole genus in the Antilocapridae family and the only species in the
Antilocapra genus – definitely a mammal that stands alone.
Pronghorns have a strictly North American lineage. Pronghorns never migrated (in either direction) across the Bering Sea land bridge nor have they ever traveled to South America. They are endemic (confined to a geographic area) to North America.
Fossil records show that during the Miocene (about 20 million years ago) a wide variety of prehistoric pronghorns roamed North America. Some of these early animals were as small as jackrabbits while others were larger than the contemporary pronghorn. The Miocene pronghorns comprised many genera and had diverse forms (forked, fan-shaped, long and slender, spirally twisted) and numbers (as many as six) of “pronghorns”.
Today only one pronghorn species remains. Pronghorns have no close living relatives and there is debate as to where they belong phylogenetically (evolutionary relationship among organisms).
Pronghorns possess great running speed and endurance. They are considered the fastest mammals in North America. Pronghorns evolved with dire wolves, short-faced bears, jaguars, North American lions, hyenas and cheetahs and were probably prey for all these animals. Running speed and endurance were survival tactics for the pronghorn during the Miocene. By the Pleistocene (about 2.5 million years ago to about 11,000 years ago) those early predators had all disappeared, however the selective pressure presented by modern-day pronghorn predators (wolves, mountain lions, man) continue to favor speed and endurance.