The Spanish Empire and other Europeans brought horses to the Americas. Some of these animals escaped and began to breed and increase their numbers in the wild. The re-introduction of the horse, extinct in the Americas for over 7500 years, had a profound impact on Native American culture in the Great Plains of North America and of Patagonia in South America. By domesticating horses, some tribes had great success: horses enabled them to expand their territories, exchange more goods with neighboring tribes, and more easily capture game, especially bison.
How long had horses been extinct in the Americas prior to their re-introduction?
7500 years