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.
List of Bureau of Land Management Herd Management Areas
Population of free-ranging horses is a concern because, unlike wildlife or livestock, horses are not hunted, do not face significant natural predators, nor are their numbers human-controlled by means of grazing permits. Without population control, their numbers can double every four years. With current management practices, numbers currently are increasing by about 15% to 18% each year. , 48,447 equines that had been captured, removed from the range were kept in holding facilities in various locations throughout the west and midwest. Many of these excess animals are eligible to be placed for "adoption" with private owners. Since 1971, about 220,000 horses and burros have been adopted through the BLM. In the early 2000s, about 8,000 horses a year were adopted, but at present, there are only about 2,500 horses adopted each year. The BLM attributes this to changing economic conditions. Of those remaining in the wild, , the estimated 67,027 horses and burros are two and a half times the population in 1971 when the Act was passed and about twice the recommended AML. Besides removal of about 3,500 animals in 2016 to long-term holding facilities and adoption, the BLM hopes to use fertility control and other tools to reduce numbers of horses on the range.