About 55 million years ago Greenland's eruption and the beginning of the formation of the Atlantic Ocean caused climate warming:.......................
"The event changed global rainfall patterns, broiled and acidified the oceans, and killed up to 50 percent of the world’s deep-sea organisms. The warm climate also opened up new migration routes for horses and other mammals into North America and might have even fueled early primate evolution."
Primates had already evolved but the event presumably separated Old World from New World monkeys.
Migration routes for horses? Horses never developed in the Americas.
Nor have their pre-historic skeletal remains ever been found.
Bison yes, not horses.
All horses in the Americas first originated when Ferdinand Pissaro brought them over by boat, to conquer the Incas
Neither the Incas, nor the N American Indians, had ever developed the wheel. So horses able to carry "the Gods" and supplies were held in awe by both nations, and frequently stolen for breeding.
