A mare is an adult
female
Female (symbol: ♀) is the sex of an organism that produces the large non-motile ova (egg cells), the type of gamete (sex cell) that fuses with the male gamete during sexual reproduction.
A female has larger gametes than a male. Females a ...
horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...
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
The Thoroughbred is a horse breed best known for its use in horse racing. Although the word ''thoroughbred'' is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are ...
horse racing, a mare is defined as a female
horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...
more than four years old. The word can also be used for other female
equine animals, particularly
mules and
zebra
Zebras (, ) (subgenus ''Hippotigris'') are African equines with distinctive black-and-white striped coats. There are three living species: the Grévy's zebra (''Equus grevyi''), plains zebra (''E. quagga''), and the mountain zebra (''E. ...
s, but a female
donkey is usually called a "jenny". A broodmare is a mare used for breeding. A horse's female parent is known as its dam.
Reproductive cycle
Mares carry their young (called
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 foal ...
s) for approximately 11 months from conception to birth. (Average range 320–370 days.)
[Ensminger, M. E. ''Horses and Horsemanship: Animal Agriculture Series.'' Sixth Edition. Interstate Publishers, 1990. p. 156] Usually just one young is born; twins are rare. When a
domesticated mare foals, she nurses the foal for at least four to six months before it is
weaned, though
mares in the wild may allow a foal to nurse for up to a year.
The
estrous cycle
The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestr ...
, also known as "season" or "heat" of a mare occurs roughly every 19–22 days and occurs from early spring into autumn. As the days shorten, most mares enter an ''anestrus'' period during the winter and thus do not cycle in this period. The reproductive cycle in a mare is controlled by the
photoperiod (length of the day), the cycle first triggered when the days begin to lengthen. As the days shorten, the mare returns to the anestrus period when she is not sexually receptive. Anestrus prevents the mare from conceiving in the winter months, as that would result in her foaling during the harshest part of the year, a time when it would be most difficult for the foal to survive.
[Ensminger, M. E. ''Horses and Horsemanship: Animal Agriculture Series.'' Sixth Edition. Interstate Publishers, 1990. p. 150]
However, for most competitive purposes, foals are given an official "birthday" of January 1 (August 1 in the
Southern Hemisphere), and many breeders want foals to be born as early in the year as possible. Therefore, many breeding farms begin to put mares "under lights" in late winter in order to bring them out of anestrus early and allow conception to occur in February or March. One exception to this general rule is the field of
endurance riding, which requires horses to be 60 true calendar months old (5 years) before competing at longer distances.
Fillies are
sexually mature
Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural defini ...
by age two and are sometimes bred at that age, but generally should not be bred until they have stopped growing, usually by age four or five.
[Ensminger, M. E. ''Horses and Horsemanship: Animal Agriculture Series.'' Sixth Edition. Interstate Publishers, 1990. p. 149-150]
A healthy, well-managed mare can produce a foal every year into her twenties, though not all breeders will breed a mare every year. In addition, many mares are kept for riding and so are not bred annually, as a mare in late
pregnancy
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ...
or nursing a foal is not able to perform at as athletic a standard as one who is neither pregnant nor
lactating
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...
. In addition, some mares become
anxious when separated from their foals, even temporarily, and thus are difficult to manage under saddle until their foals are
weaned.

The formation of the bond between a mare and her foal "occurs during the first few hours
post-partum , but that of the foal to the mare takes place over a period of days".
Behavior
Mares are considered easier to handle than
stallion
A stallion is a male horse that has not been gelded (castrated).
Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" nec ...
s.
In wild herds, a "boss mare" or "lead mare" leads the band to grazing, to water, and away from danger. She eats and drinks first, decides when the herd will move and to where. The herd stallion usually brings up the rear and acts as a defender of the herd against predators and other stallions.
Uses

Mares are used in every
equestrian sport and usually compete equally with stallions and geldings in most events, though some competitions may offer classes open only to one sex of horse or another, particularly in
breeding or "in-hand" conformation classes. In
horse racing, mares and fillies have their own races and only a small percentage compete against male horses. However, a few fillies and mares have won classic horse races against colts, including the Prix de l'Arc de Triomphe, the
Kentucky Derby
The Kentucky Derby is a horse race held annually in Louisville, Kentucky, United States, almost always on the first Saturday in May, capping the two-week-long Kentucky Derby Festival. The competition is a Grade I stakes race for three-yea ...
, the
Preakness Stakes
The Preakness Stakes is an American thoroughbred horse race held on Armed Forces Day which is also the third Saturday in May each year at Pimlico Race Course in Baltimore, Maryland. It is a Grade I race run over a distance of 9.5 furlongs ...
, the
Belmont Stakes, the
Melbourne Cup and the
Breeders' Cup Classic.
Mares are used as
dairy animals in some cultures, especially by the
nomads
A nomad is a member of a community without fixed habitation who regularly moves to and from the same areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the po ...
and formerly nomadic peoples of
Central Asia
Central Asia, also known as Middle Asia, is a region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes the former ...
. Fermented
mare's milk, known as
kumis, is the national drink of
Kyrgyzstan
Kyrgyzstan,, pronounced or the Kyrgyz Republic, is a landlocked country in Central Asia. Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the south, and the People's Republic of China to the ea ...
. Some mares, usually of
draft horse
A draft horse (US), draught horse (UK) or dray horse (from the Old English ''dragan'' meaning "to draw or haul"; compare Dutch ''dragen'' and German ''tragen'' meaning "to carry" and Danish ''drage'' meaning "to draw" or "to fare"), less o ...
breeding, are kept in North America for the production of their urine. Pregnant mares' urine is the source of the
active ingredient in the hormonal drug
Premarin (derived from Pregnant mares' urine).
Until the invention of
castration, and even later where there was less cultural acceptance of castration, mares were less difficult to manage than stallions and thus preferred for most ordinary work. Historically, the
Bedouin nomads of the
Arabian peninsula preferred mares on their raids, because stallions would nicker to the opposing camps' horses, whereas mares would be quiet. However, other cultures preferred male horses over mares either due to a desire for more aggressive behavior in a fighting animal, or to not be inconvenienced with a loss of work ability due to a mare's pregnancy,
parturition and
lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The pr ...
.
Etymology
The word ''mare'', meaning "female horse", took several forms before A.D. 900. In
Old English the form was ''mīere'', ''mere'' or ''mȳre'', the
feminine forms for ''mearh'' (horse). The
Old German form of the word was ''Mähre''.
Similarly, in
Irish and
Gaelic, the word was ''marc'', in
Welsh
Welsh may refer to:
Related to Wales
* Welsh, referring or related to Wales
* Welsh language, a Brittonic Celtic language spoken in Wales
* Welsh people
People
* Welsh (surname)
* Sometimes used as a synonym for the ancient Britons (Celtic peopl ...
, ''march'', in Cornish "margh", and in
Breton ''marc'h''.
The word is "said to be of Gaulish origin."
It is said by some writers to derive from
Proto-Germanic
Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed proto-language of the Germanic branch of the Indo-European languages.
Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic bran ...
*''marhijō'' ("female horse"), from Proto-Germanic ''marhaz'' ("horse"), from
Proto-Indo-European
Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo- ...
*''markos'' ("horse").
The word has no known
cognates beyond
Germanic and
Celtic.
However, an interesting hypothesis links these Indo-European words to Mongolian морь
[Wiktionary entry for Mongolian морь (mori, horse)](_blank)
/ref> (mori, horse).
[Articl]
"Of horse riding and Old Sinitic reconstructions"
on Language Log at the University of Pennsylvania.
[Articl]
"Mare, mǎ, etc."
on Language Log at the University of Pennsylvania.
In addition, the Wiktionary entry for морь includes a comparison to possibly related words for horse in Korean, Manchu, Chinese (馬/马 mǎ), Japanese (うま uma), and others.
One possible derived term is a ''mare's nest'', an expression for "excitement over something which does not exist".[Etymology OnLine](_blank)
, accessed November 25, 2007
The term '' nightmare'', is not directly connected etymologically with the word for female horse, but rather to homophone
A homophone () is a word that is pronounced the same (to varying extent) as another word but differs in meaning. A ''homophone'' may also differ in spelling. The two words may be spelled the same, for example ''rose'' (flower) and ''rose'' (pa ...
s that meant "incubus" or "goblin".
See also
*Horse breeding
Horse breeding is reproduction in horses, and particularly the human-directed process of selective breeding of animals, particularly purebred horses of a given breed. Planned matings can be used to produce specifically desired characteristics i ...
*Stallion
A stallion is a male horse that has not been gelded (castrated).
Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" nec ...
*Gelding
A gelding is a castration, castrated male horse or other equine, such as a pony, donkey or a mule. Castration, as well as the elimination of hormonally driven horse behavior, behavior associated with a stallion, allows a male equine to be calmer a ...
* Filly
*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 foal ...
*Colt (horse)
A colt is a male horse, usually below the age of four years.
Description
The term "colt" only describes young male horses and is not to be confused with foal, which is a horse of either sex less than one year of age. Similarly, a yearling is ...
References
{{reflist
Types of horse
Horse breeding and studs
Female horses
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