Saturday, February 9, 2013

Pronghorn Antelope

Pronghorns are not true antelopes, but examples of convergent evolution, wherein unrelated animals evolve in response to similar habitats so as to resemble one another. Rather than being an antelope of the Old World, the Pronghorn is the only surviving member of the family Antilocapridae (Wikipedia). Pronghorns are found in the Great Plains of southern Canada south into northern Mexico. Pronghorns rarely seen in western Minnesota are likely to be wanderers from South Dakotan herds. This photo was taken north of Fort Pierre along the western shore of the Missouri River.

In our region, Pronghorns become more common the further west you travel. Your chances increase when you cross the Missouri River in South Dakota and you can usually see them by the time you cross into Wyoming. In the 1920s, presumably due to overhunting, Pronghorn populations declined to about 13,000. They have now rebounded to about a million, and, in fact, may outnumber people in Wyoming (Wikipedia). East River populations in South Dakota were decimated (and perhaps extirpated) by blizzards in the late 1800s and 1940s. The animals have been reintroduced to these regions, but suffer from competition from livestock, sheep diseases, and prairie fragmentation.

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