It's theorized that although horses and other ungulates may have originated in the Americas, climactic shifts gradually raised the silica content of grasses, driving them out as the remaining populations slowly starved from grinding their teeth down too fast.
deleted by creator
Or teeth, grass is really tough on teeth.
It's theorized that although horses and other ungulates may have originated in the Americas, climactic shifts gradually raised the silica content of grasses, driving them out as the remaining populations slowly starved from grinding their teeth down too fast.
Fucking cool. Never heard that hypothesis before
eh, I find the theory human populations killed and ate all of them more compelling.