The African cheetah is commonly recognized as the world’s fastest land mammal — but few people have heard of the American cheetah (Miracinonyx), an extinct genus of two feline species that were endemic to North America during the Pleistocene period.
Researchers have pieced together fragments of skeleton and over time developed theories regarding the evolution of this mysterious animal, but they have been met with much controversy along the way.
Initially, the animal was assigned to the genera Felis, Puma and Acinonyx until it was considered distinct enough to label as its own genus, Miracinonyx. The two species officially identified as belonging to this genus were Miracinonyx inexpectatus and M. trumani.
Both species were similar to the modern cheetah, boasting shortened faces and expanded nasal cavities, in addition to powerful legs developed for running.
Although African and American cheetahs share many similar traits, taxonomically they were not related enough to be assigned to the same genus. There is much scientific debate regarding the evolutionary relationship between modern and extinct American cheetahs.
American cheetahs were estimated to have weighed about 150 pounds and measured five feet in body length. M. inexpectatus had shorter legs that were thought to be better equipped for climbing than the modern cheetah.
The two species seem to have shared some important general characteristics, including a preference for open grassland areas and the ability to attain very fast speeds.
American cheetahs most likely fed primarily on American pronghorn, which are the second fastest land mammals on the planet. Other prey may have included extinct mountain sheep and horses.
Although there are still controversies regarding the evolution of the American cheetah, it is certain this was an impressive and influential animal in the development of our modern wildlife.
Scientists have long speculated that the American cheetah may have been the contributing factor behind the evolution of the American pronghorn’s remarkable speed.