Meet the pronghorn. They're built for maximum evasion from predators through running and are considered to be the fastest land mammal on the North American continent. The top speed is hard to measure accurately and varies between individuals but they have been clocked at over 50 mph. They have very large eyes, possess a 320 degree field of vision and are quite skittish; I tried many times to get close. This shot that I consider my best was taken in South Dakota, required a blind and a lot of patience.