A filly is a female horse that is too young to be called a

mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than fo ...

. There are two specific definitions in use: *In most cases, a ''filly'' is a female horse under four years old. *In some nations, such as the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...

and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, the world of

horse racing Horse racing is an equestrian performance sport, typically involving two or more horses ridden by jockeys (or sometimes driven without riders) over a set distance for competition. It is one of the most ancient of all sports, as its basic pr ...

sets the cutoff age for fillies as five. Fillies are sexually mature by two and are sometimes bred at that age, but generally, they should not be bred until they themselves have stopped growing, usually by four or five.Ensminger, M. E. ''Horses and Horsemanship: Animal Agriculture Series.'' Sixth Edition. Interstate Publishers, 1990. p. 149-150 Some fillies may exhibit estrus as yearlings. The equivalent term for a male is a colt. When horses of either sex are less than one year, they are referred to as

foal A foal is an equine up to one year old; this term is used mainly for horses, but can be used for donkeys. More specific terms are colt for a male foal and filly for a female foal, and are used until the horse is three or four. When the foa ...

s. Horses of either sex between one and two years old may be called yearlings.

References

{{Reflist Types of horse Female horses

See also

References