A mare is an adult or other .
In most cases, a mare is a female horse over the age of three, and a is a female horse three and younger. In , a mare is defined as a female more than four years old. The word can also be used for other female animals, particularly and , but a female is usually called a « jenny ». A broodmare is a mare used for breeding. A horse’s female parent is known as its dam.
An uncastrated adult male horse is called a and a male is a . Occasionally, the term « horse » is used to designate only a male horse.
Mares carry their young (called ) for approximately 11 months from conception to birth. (Average range 320–370 days.) Usually just one young is born; twins are rare. When a mare foals, she nurses the foal for at least four to six months before it is , though may allow a foal to nurse for up to a year.
The , 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 (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.
However, for most competitive purposes, foals are given an official « birthday » of January 1 (August 1 in the ), 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 , which requires horses to be 60 true calendar months old (5 years) before competing at longer distances.
Fillies are by age two and are sometimes bred at that age, but generally should not be bred until they themselves have stopped growing, usually by age four or five.
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 or nursing a foal is not able to perform at as athletic a standard as one who is neither pregnant nor . In addition, some mares become from their foals, even temporarily, and thus are difficult to manage under saddle until their foals are .
Mares are considered easier to handle than . However, have little to no hormone-driven behavior patterns at all, thus sometimes they are preferred to both mares and stallions. Mares have a notorious, if generally undeserved, reputation for being « marish, » meaning that they can be cranky or unwilling when they come into .
While a few mares may be somewhat more distractible or irritable when in heat, they are far less easily distracted than a stallion at any time. Solid training usually minimizes hormonal behavior. For competitive purposes, mares are sometimes placed on , such as the drug Regumate, to help control hormonally based behavior. Some riders also use various , most of which have not been extensively tested for effectiveness.
In relation to maternal behaviour, 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 ».
Mares and geldings can be pastured together. However, mares may be a bit more territorial than geldings, even though they are far less territorial than stallions. Sex-segregating herds may make for less infighting, especially if kept in close quarters. However, studies also have shown that when a « lead mare » or « boss mare » is in charge of a herd, all remaining animals rest for longer periods and seem more at ease than do those in herds led by a gelding.
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.
Mares are used in every 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 classes. In , 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 , the , the , the and the .
Mares are used as animals in some cultures, especially by the and formerly nomadic peoples of . Fermented , known as , is the national drink of . Some mares, usually of breeding, are kept in North America for the production of their urine. Pregnant mares’ urine is the source of the in the hormonal drug (derived from Pregnant mares’ urine).
Until the invention of and even later where there was less cultural acceptance of the practice, mares were less difficult to manage than stallions and thus preferred for most ordinary work. Historically, the nomads of the 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, and .
The word mare, meaning « female horse », took several forms before A.D. 900. In the form was mere or mȳre, the for mearh (horse). The form of the word was Mähre. Similarly, in and , the word was marc, in , march, in Cornish « margh », and in marc’h. The word is « said to be of Gaulish origin. » The word has no known beyond and . One possible derived term is a mare’s nest, an expression for « excitement over something which does not exist » The term , is not directly connected etymologically with the word for female horse, but rather to that meant « incubus » or « goblin. »