Horse
Depending on breed, management and environment, the modern domestic horse has a life expectancy of 25 to 30 years. Uncommonly, a few animals live into their 40s and, occasionally, beyond. The oldest verifiable record was "Old Billy", a 19th-century horse that lived to the age of 62. In modern times, Sugar Puff, who had been listed in "Guinness World Records" as the world's oldest living pony, died in 2007 at age 56.
Horses in the United States
A 2005 genetic study of fossils found evidence for three genetically divergent equid lineages in Pleistocene North and South America. Recent studies suggest all North American fossils of caballine-type horses, including both the domesticated horse and Przewalski's horse, belong to the same species: "E. ferus". Remains attributed to a variety of species and lumped as New World stilt-legged horses probably all belong to a second closely related species that was endemic to North America. Digs in western Canada have unearthed clear evidence horses existed in North America as recently as 12,000 years ago. Other studies produced evidence that horses in the Americas existed until 8,000–10,000 years ago.