North America also lost its many camels, which originated and evolved on the continent, only later spreading out into Asia and Africa. When camels were experimentally employed in military convoys across the Southwest in the 1850s, Lieutenant Edward Beale - unaware of the animals’ ancestral connection to the land—was pleasantly surprised by their uncommon effectiveness. Happily marching across their evolutionary homeland, they ate “the otherwise worthless weeds and other plants shunned by livestock, including creosote bush growing along the right of way in New Mexico.” North America lost its American zebras as well as its horses.

The story of horses in North America is a curious one. Horses evolved on the continent over millions of years, then suddenly went extinct around 12,000 years ago, only to be reintroduced a few thousand years later by Spanish colonists. If they persist on the continent for millions of years from now, geologists of the far future probably won’t detect this strange millennia-long absence.

— Ends of the World by Peter Brannen (Page 56)