Lifespan and life stages

Lifespan and life stages

Depending on breed, management and environment, the domestic horse today has a life expectancy of 25 to 30 years.^[4] It is uncommon, but a few animals live into their 40s and, occasionally, beyond.^[5] The oldest verifiable record was "Old Billy", a 19th-century horse that lived to the age of 62.^[4] In modern times, Sugar Puff, who had been listed in the Guinness Book of World Records as the world's oldest living pony, died in 2007, aged 56.^[6]
Regardless of a horse's actual birth date, for most competition purposes an animal is considered a year older on January 1 of each year in the northern hemisphere^[4][7] and August 1 in the southern hemisphere.^[8] The exception is in endurance riding, where the minimum age to compete is based on the animal's calendar age.^[9] A very rough estimate of a horse's age can be made from looking at its teeth.^[4]
The following terminology is used to describe horses of various ages:

• Foal: a horse of either sex less than one year old. A nursing foal is sometimes called a suckling and a foal that has been weaned is called a weanling.^[10] Most domesticated foals are weaned at 5 to 7 months of age, although foals can be weaned at 4 months with no adverse effects.^[11]
• Yearling: a horse of either sex that is between one and two years old.^[12]
• Colt: a male horse under the age of four.^[13] A common terminology error is to call any young horse a "colt", when the term actually only refers to young male horses.^[14]
• Filly: a female horse under the age of four.^[10]
• Mare: a female horse four years old and older.^[15]
• Stallion: a non-castrated male horse four years old and older.^[16] Some people, particularly in the UK, refer to a stallion as a "horse".^[17]
• Gelding: a castrated male horse of any age.^[10]

In horse racing, these definitions may differ: For example, in the British Isles, Thoroughbred horse racing defines colts and fillies as less than five years old.^[18] However, for Australian Thoroughbred racing, colts and fillies are less than four years old.^[19]