Equus mexicanus Age: Pleistocene (13,000 -6,000 years ago) Location: Trinity River Gravel, Dallas County, Texas, USA
The rich grasslands than covered North America in the Eocene lead to a proliferation of grassland animals including the ancestor of the horse, by the beginning of the last age there were multiple species of horses across North and South America. The late Pleistocene marked the decline of much of the North and South American megafauna. The North American wild horse species became extinct at some period between 13,000 and 6,000 years ago. This sudden decline is unlikely to be completely due to the climatic changes of the retreating and advancing ice sheets and the arrival of early humans in the continent may have been a contributing factor.