The horse is a beautiful and majestic animal. Its physical strength and ability for speed is in stark contrast to its sensitive digestive system and need for companionship. For hundreds of years humans have tamed, trained, studied, used and worshipped the horse, not necessarily in that order. For those who have not lived a life on the farm or around equine, the life of a horse exists in a few stages depending on the sex: foal, yearling, colt, filly, mare, stallion, gelding.

The average lifespan of a healthy horse is 25 to 30 years, but some have been known to live into their 40's and 50's. Most of the time, the birth date of a horse is kept track of but general practice is rolling over a horse's age by one year every January first. The only exception is in the sport of endurance riding where the exact calendar age is required for qualification. If the age of the horse is unknown, a general idea can be gained from examining the teeth.

Foal

A foal is a horse under one year of age, and of either sex. Colt is the specific term of a male foal and filly for a female. A foal that is still nursing may be referred to as a suckling, and its mother a dam. Most domesticated foals are weaned around the four to six month range, while wild foals may nurse for longer. When a foal is born it can stand within 30 minutes, canter within a few hours and gallop within 24 hours. For the first ten days of life the foal will only feed on the mother's milk, after that solids are introduced. A foal should gain at least three pounds per day, thus their physical growth is rapid. Their mental maturity is not as fast, but they can respond to some basic training - riding and driving not included.

Yearling

A yearling is a horse that is one to two years old, of either gender. The terms colt and filly are still applied during the yearling stage, and often up until the horse is three or four years of age. A yearling can be compared in maturity to a human adolescent. Their physical growth is not quite complete, they are not sexually mature and training is still in the early stages. If the yearling will not be used to breed, then gelding occurs at this time to aid in behavioural training. If breeding is an option, then many owners will train the yearling for showing or try to find a buyer.

Colt/Filly

As previously stated, colt is a male horse under the age of four and filly is a female horse under the age of four.

Gelding/Stallion

When a colt is over the age of four and has not been gelded, he is then referred to as a stallion or full horse. Stallions are prized among horse enthusiasts for obvious breeding reasons, but also for their strong instinctual habits. They can be trained, with care, but must be monitored carefully as it is a stallion's natural instinct to exhibit aggression towards other stallions. In general the behaviour of a stallion is more challenging, but depending on genetics and training the stallion can be used in high level work such as racing and the Olympics. A gelding is a horse in which the testicles have been removed. The decision to castrate a horse may be done for the purposes of training, safety, herding, the gene pool, and even personal preference. If a horse is meant to become a member of a herd for its lifetime, then gelding is important to avoid conflict with stallions. In the case of training, gelded horses are more easily trained and manipulated.

Mare

A mare is a female horse over the age of four. A mare used for the sole purpose of breeding is a broodmare. Mares are sexually mature from age two, but should not be bred before they stop growing at age four. The cycles of a mare occur in 19 to 22 day cycles from early spring to late autumn, and cease in winter. A mare carries its foal for 11 months before giving birth, usually quite quickly and during the night. In sport and work, mares are prized as easy to train, intelligent, hard working and courageous.