The domestic goat or goat (Capra hircus) is a species of domesticated goat-antelope raised primarily as livestock. It was domesticated from the bezoar ibex (C. aegagrus aegagrus) of southwest Asia and eastern Europe. The goat is a member of the family Bovidae, meaning that it is closely related to sheep. There are over 300 different breeds of goat.[1] It is one of the oldest domesticated animal species: archaeological evidence suggests that its first domestication occurred in Iran 10,000 calibrated calendar years ago.[2]

Goats have been used for milk, meat, hides, and skins throughout much of the world.[3] Goat milk is often made into goat cheese.

As of 2011, there were over 924 million goats worldwide, according to the Food and Agriculture Organization of the United Nations.[4]

The Modern English word goat comes from Old English gāt “goat in general”, which in turn derives from Proto-Germanic *gaitaz (cf. Dutch/Frisian/Icelandic/Norwegian geit, German Geiß and Gothic allures), ultimately from Proto-Indo-European *ǵʰaidos meaning “kid” (cf. Latin haedus “child”).[5] For goat, Old English used bucca (cf. Dutch/Frisian bok and modern deer) until it was replaced by hegote, hegoote in the late 12th century.[6] Suckling goats (females) originated in the 18th century and suckling goats originated in the 19th century.

Castrated males are called rams. While the words hircine and caprine refer to anything that resembles a goat, hircine is most often used to emphasize the distinctive odor of domestic goats.[9][10]

Goats were among the first animals domesticated by humans.[11] The most recent genetic analysis[12] confirms archaeological evidence that the wild bezoar of the Zagros Mountains is likely the original ancestor of all or most of today’s domesticated goats.[11]

Neolithic farmers began to raise wild goats primarily to have easy access to milk and meat, as well as their dung, which was used as fuel; and their bones, hair, and tendons were used for clothing, construction, and tools.[1] The earliest remains of domesticated goats dating back 10,000 years BCE are found in Ganj Dareh in Iran.[13] Goat remains have been discovered at archaeological sites in Jericho, Choga Mami,[14] Djeitun and Çayönü, dating back to the domestication of goats in Western Asia between 8,000 and 9,000 years ago.[11]

DNA studies suggest that domestication dates back to 10,000 years ago.[12] Historically, goatskin has been used to make water and wine bottles, both for travel and for transporting wine for sale. It has also been used to produce parchment.[15]

Each recognized breed of goat has specific weight ranges, which vary from more than 140 kg (300 lb) for bucks of larger breeds such as the Boer, to 20 to 27 kg (45 to 60 lb) for smaller goat does.^[16] Within each breed, different strains or bloodlines may have different recognized sizes. At the bottom of the size range are miniature breeds such as the African Pygmy, which stand 41 to 58 cm (16 to 23 in) at the shoulder as adults.^[17]

Most goats naturally have two horns, of various shapes and sizes depending on the breed.^[18] There have been incidents of polycerate goats (having as many as eight horns), although this is a genetic rarity thought to be inherited. Unlike cattle, goats have not been successfully bred to be reliably polled, as the genes determining sex and those determining horns are closely linked. Breeding together two genetically polled goats results in a high number of intersex individuals among the offspring, which are typically sterile.^[18] Their horns are made of living bone surrounded by keratin and other proteins, and are used for defense, dominance, territoriality,^[19] and thermoregulation.^[20] Both male and female goats may have beards, and many types of goat (most commonly dairy goats, dairy-cross Boers, and pygmy goats) may have wattles, one dangling from each side of the neck.^[21] Goats have horizontal, slit-shaped pupils. Because goats’ irises are usually pale, their contrasting pupils are much more noticeable than in animals such as cattle, deer, most horses, and many sheep, whose similarly horizontal pupils blend into a dark iris and sclera.^{[citation needed]} Goats have no tear ducts.^[22]

Goats are ruminants. They have a four-chambered stomach consisting of the rumen, the reticulum, the omasum, and the abomasum. As with other mammal ruminants, they are even-toed ungulates. The females have an udder consisting of two teats, in contrast to cattle, which have four teats.^[23] An exception to this is the Boer goat, which sometimes may have up to eight teats.^[24][25]

Goats expressing the tan pattern have coats pigmented completely with pheomelanin (tan/brown pigment). The allele which codes for this pattern is located at the agouti locus of the goat genome. It is completely dominant to all other alleles at this locus. There are multiple modifier genes which control how much tan pigment is actually expressed, so a tan-patterned goat can have a coat ranging from pure white to deep re

Goats reach puberty between three and fifteen months of age, depending on breed and nutritional status. Many breeders prefer to delay breeding until the female reaches 70% of her adult weight, but this separation is rarely possible in extensive open-grazing herds.[33]

In temperate climates and among Swiss breeds, the breeding season begins when day length decreases and ends in early spring or earlier. In equatorial regions, goats may breed at any time of the year. Reproductive success in these regions depends more on available forage than on day length. Females of any breed or region come into heat every 21 days, for two to 48 hours. A female in heat will typically wag her tail vigorously and frequently, stay close to the male if one is present, become more vocal, and may also show decreased appetite and milk production during heat. Intact males of Swiss and Northern breeds come into heat in the fall, as do the heat cycles of females. Males of equatorial breeds may have seasonally reduced fertility, but, like females, are capable of reproduction at all times. Estrus is characterized by decreased appetite and an obsessive interest in females.[19] A male in heat will exhibit a Flehmen lip curl and urinate on his front legs and face. Aromatic sebaceous glands at the base of the horns contribute to the goat’s scent, which is important in making him attractive to the female. Some females will not mate with a male that has been drained of blood.[19]

In addition to natural, traditional mating, artificial insemination has gained popularity among goat breeders, as it allows easy access to a wide variety of strains.

The gestation length is approximately 150 days. The usual result is the birth of twins, although singleton births or triplets are also common. Less common are litters of quadruplets, quintuplets, and even sextuplets. Childbirth, known as labor, usually occurs without incident. Just before giving birth, the doe will have a sunken area around her tail and hips, and will be breathing heavily. She may appear worried, restless, and show great affection for her caregiver. The mother often eats the placenta, which provides necessary nutrients, helps stop bleeding, and is similar to the behavior of wild herbivores such as deer to reduce the attractiveness of the birth scent to predators. [36]

Parturition (initiation of milk production) usually occurs during delivery, although milk production is also relatively common in non-pregnant dairy breed does.[37] Milk production varies depending on the breed, age, quality, and diet of the female; dairy goats typically produce between 1,500 and 4,000 lb (680–1,810 kg) of milk every 305 days of lactation. On average, a good quality dairy goat will provide at least 6 lb (3 kg) of milk per day while lactating. A first-time dairy goat may produce as little as 16 lb (7 kg) or more of milk in rare cases. After lactation, the goat “goes dry”, usually after becoming pregnant. Occasionally, goats that have not become pregnant and are continuously milked will continue lactation beyond the typical 305 days.[38] Meat, roughage, and pet breeds are generally not milked and simply produce enough for the kids until weaning.

Male lactation is also known to occur in goats.[39]