American Cheetah (Miracinonyx)

The American Cheetah was more closely related to this modern cougar.

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American Cheetah; also known as Miracinonyx; pronounced MEE-rah-SIN-oh-nix


Plains of North America

Historical Period:

Pleistocene-Modern (2 million-10,000 years ago)

Size and Weight:

About six feet long and 100-150 pounds, depending on species



Distinguishing Characteristics:

Long legs; lithe body; blunt snout; foreshortened face with enlarged nasal cavities (to allow for more efficient respiration) 

About the American Cheetah (Miracinonyx)

Like the American Lion, the American Cheetah (genus name Miracinonyx) may yet turn out to have a misleading nickname; there's an argument to be made that this predator of Pleistocene North America was more closely related to modern pumas and cougars than it was to cheetahs. If, in fact, the American Cheetah turns out not to have been a true cheetah, you can chalk the confusion up to convergent evolution, the tendency for animals in the same ecosystems to evolve the same general features: like modern cheetahs, the lithe, long-legged Miracinonyx made its living by pursuing speedy mammalian megafauna, including deer and prehistoric horses, across the rolling North American plains. However, there's no way to know if Miracinonyx could achieve Cheetah-like bursts of speed in the 50-mile-per-hour range, or if its speed limit was set by evolution to a much lower level.

Adding to the uncertainty about its name, the American Cheetah comprises two very different species (Miracinonyx trumani and Miracinonyx inexpectatus), which may potentially wind up being assigned to different genera, depending on future fossil discoveries. M. trumani more closely resembled a modern cheetah, and may have been capable of hitting top speeds of over 50 miles per hour in pursuit of prey, as referenced above. M. inexpectatus was built more like a cougar than a cheetah (though it was somewhat slimmer overall), and its fully retractable claws point to a possible arboreal lifestyle --that is, instead of chasing prey over the prairies like M. trumani, it may have leaped on them from the low branches of trees, or perhaps scrambled up trees to escape the notice of larger predators. (What was once considered a third Miracinonyx species, M. studeri, is now classified as an M. trumani subspecies).