Continuing my series on Winter Wildlife: The Pronghorn.
"Of all the animals we have seen the Antelope (Pronghorn) seems to possess the most wonderful fleetness. Shy and timorous they generally repose only on the ridges, which command a view of all the approaches of an enemy." Lewis and Clark.
It is true, Pronghorn have very large eyes which can detect movement from 4 miles away with 320 degree vision.
It is also true, Pronghorn are the fastest mammals in the Western Hemisphere and the second fastest mammal in the world (second only to the Cheetah). Actually the Pronghorn can maintain their speed longer than the Cheetah.
The pronghorn has a large windpipe, heart, and lungs which allow it to take in large amounts of air while it runs. They also have a very light bone structure with two long, cushioned, pointed toes which aid in running at high speeds.
They are built for speed and not jumping. So they can't (don't) jump fences like deer. They will go under fences instead of over them. Ranchers have been removing the barbed wire from the bottom of their fences and replacing it with barbless wire to lessen the damage to the Pronghorn.
Pronghorn's primary range in the US is Montana through Eastern Oregon, Wyoming, Colorado, and Arizona, though they can also be found in Minnesota, South Dakota, West Texas, Utah and Nevada. There is a subspecies, the Sonoran Pronghorn, in Southern Arizona and Mexico that is endangered. The US population of the Sonoran Pronghorn is less than 500.
Below are "winter" photos of Pronghorn from Montana. I like the first because it seems like a Japanese silk painting.