Polyandry (Ancient Greek: polys—many, anēr—man) is a form of polygamy whereby a woman takes two or more husbands at the same time. Polyandry is contrasted with polygyny, involving one male and two or more females. Polyandry is also distinct from group marriage, involving plural participants of each sex.
According to the Ethnographic Atlas, of 1,231 societies noted, 186 were monogamous; 453 had occasional polygyny; 588 had more frequent polygyny; and 4 had polyandry. Polyandry is less rare than this figure which listed only those examples found in the Himalayan Mountains. More recent studies have found 53 societies outside of the 28 found in the Himalayans which practice polyandry.
Fraternal polyandry was traditionally practiced among Tibetans in Nepal, parts of China and part of northern India, in which two or more brothers are married to the same wife, with the wife having equal 'sexual access' to them. It is most common in egalitarian societies marked by high male mortality or male absenteeism. It is associated with partible paternity, the cultural belief that a child can have more than one father.
Polyandry is believed to be more likely in societies with scarce environmental resources, as it is believed to limit human population growth and enhance child survival. It is a rare form of marriage that exists not only among poor families, but also the elite. For example, in the Himalayan Mountains polyandry is related to the scarcity of land; the marriage of all brothers in a family to the same wife allows family land to remain intact and undivided. If every brother married separately and had children, family land would be split into unsustainable small plots. In Europe, this was prevented through the social practice of impartible inheritance (the dis-inheriting of most siblings, many who went on to become celibate monks and priests).
In zoology, polyandry is a mating system involving a female and two or more males. Most broadly, polyandry refers to sexual relations with multiple males, within or without marriage.
In the Indian Himalayas, polyandry may be combined with polygyny to produce a system termed "polygynandry". The system results in less land fragmentation, a diversification of domestic economic activities, and lower population growth.
Fraternal polyandry (from the Latinfrater—brother) is a form of polyandry in which a woman is married to two or more men who are one another's brothers. Fraternal polyandry is found in certain areas of Tibet and Nepal, where polyandry is accepted as a social practice. The Toda people of southern India practice fraternal polyandry, but monogamy has become prevalent recently. In contemporary Hindu society, polyandrous marriages in the agrarian societies in Malwa region of Punjab are occurring to avoid division of farming land.
Fraternal polyandry achieves a similar goal to what primogeniture did in 19th-century England. Primogeniture dictated that the eldest son inherited the family estate, while younger sons had to leave home and seek their own employment. Primogeniture maintained family estates intact over generations by permitting only one heir per generation. Fraternal polyandry also accomplishes this, but does so by keeping all the brothers together with just one wife so that there is only one set of heirs per generation. This strategy appears less successful the larger the fraternal sibling group.
Some forms of polyandry appear to be associated with a perceived need to retain aristocratic titles or agriculturallands within kin groups, and/or because of the frequent absence, for long periods, of a man from the household. In Tibet the practice was particularly popular among the priestly Sakya class.
An extreme gender imbalance has been suggested as a justification for polyandry. For example, the selective abortion of female fetuses in India has led to a significant margin in sex ratio and, it has been suggested, results in related men "sharing" a wife.
Anthropologist Stephen Beckerman points out that at least 20 tribal societies accept that a child could, and ideally should, have more than one father, referring to it as "partible paternity." This often results in the shared nurture of a child by multiple fathers in a form of polyandric relation to the mother, although this is not always the case. One of the most well known examples is that of Trobriand "virgin birth." The matrilineal Trobriand Islanders recognize the importance of sex to reproduction but do not believe the male makes a contribution to the constitution of the child, who therefore remains attached to their mother's lineage alone. The mother's non-resident husbands are not recognized as fathers, although the mother's co-resident brothers are, since they are part of the mother's lineage.
Among the Irigwe of Northern Nigeria, women have traditionally acquired numerous spouses called "co-husbands."
Guanches from Gran Canaria practized polyandry before the Spanish conquest. According to European accounts, during a great famine in 14th or 15th century, girls were killed after coming to life in order to equilibrate demography. This resulted in a surplus of males and a shortage of females, which led to the adoption of polyandry.
In August 2013, two Kenyan men entered into an agreement to marry a woman with whom they had both been having an affair. Kenyan law does not explicitly forbid polyandry, although it is not common custom.
Sepulcral inscription for Allia Potestas, Museo Epigrafico, Terme di Diocleziano, Rome
"According to Julius Caesar, it was customary among the ancient Britons for brothers, and sometimes for fathers and sons, to have their wives in common."
"Polyandry prevailed among the Lacedaemonians according to Polybius." "(Polybius vii.7.732, following Timæus)"
"The matrons of Rome flocked in great crowds to the Senate, begging with tears and entreaties that one woman should be married to two men."
The gravestone of Allia Potestas, a woman from Perusia, describes how she lived peacefully with two lovers, one of whom immortalized her in this famous epigrafic eulogy, dating (probably) from the second century. 
Polyandry was widely (and to some extent still is) practised in Lahaul-Spiti situated in isolation in the high Himalayas in India.
In Arabia (southern) "All the kindred have their property in common ...; all have one wife" whom they share.
"In certain cantons of Media, ... a woman was allowed to have many husbands, and they looked with contempt on those who had less than five."
Among the Hephthalites, "the practice of several husbands to one wife, or polyandry, was always the rule, which is agreed on by all commentators. That this was plain was evidenced by the custom among the women of wearing a hat containing a number of horns, one for each of the subsequent husbands, all of whom were also brothers to the husband. Indeed, if a husband had no natural brothers, he would adopt another man to be his brother so that he would be allowed to marry."
In Bhutan in 1914, polyandry was "the prevailing domestic custom."
"A 1981 survey ... in Muli found 52% of the marriages engaged in monogamy, 32% practiced polyandry (brothers sharing a wife), and 16% practiced polygyny (sisters sharing a husband)."
The Hoa-tun (Hephthalites, White Huns) "living to the north of the Great Wall ... practiced polyandry."
Among the Gilyaks of Sakhalein Island "polyandry is also practiced."
Fraternal polyandry is permitted in Sri Lanka under Kandyan Marriage law, often described using the euphemism eka-ge-kama (literally "eating in one house"). Associated Polyandry, or polyandry that begins as monogamy, with the second husband entering the relationship later, is also practiced and it sometimes initiated by the wife.
Among the Kanak of New Caledonia, "every woman is the property of several husbands. It is this collection of husbands, having one wife in common, that...live together in a hut, with their common wife."
Friedrich Ratzel in The History of Mankind reported in 1896 that in the New Hebrides there was a kind of convention in cases of widowhood, that two widowers shall live with one widow. Additionally that in New Ireland and New Britain widows were claimed as common property by all the men.
According to inscriptions describing the reforms of the Sumerian king Urukagina of Lagash (ca. 2300 BC), the former custom of polyandry in his country was abolished, on pain of the woman taking multiple husbands being stoned with rocks upon which her crime is written.
Polyandrous relations are disapproved of in most expressions of Hinduism. There is at least one reference to polyandry in the ancient Hindu epic Mahabharata. Draupadi marries the five Pandava brothers. This ancient text remains largely neutral to the concept of polyandry, accepting this as her way of life. However, in the same epic, when questioned by Kunti to give an example of polyandry, Yudhisthira cites Gautam-clan Jatila (married to seven Saptarishis) and Hiranyaksha's sister Pracheti (married to ten brothers), thereby implying a more open attitude toward polyandry in Vedic society.
Technically speaking Draupadi was married to five different men, though they all were born to the same mother, who had five different men to father her children. It is said in GOTHRA or lineage history that they were considered not as biological brothers coming from a same father because Yuddhishthira was fathered by Dharma, Arjuna by Indra, Bhima by Vayu, Nakula and SahaDeva by Ashvinikumars. They came from different fathers as Pandu could not have progeny due to impotence.
The Hebrew Bible contains no examples of women married to more than one man, but its description of adultery clearly implies that polyandry is unacceptable and the practice was never permitted in Jewish tradition. In addition, the children from such relationships are considered illegitimate (i.e., a mamzer).
Islam also prohibits polyandry.Nikah Ijtimah is a pagan tradition of polyandry predating Islam which was forbidden to Muslims.
The queen bee is usually the only female bee within a hive reproducing with drones, which often come from various hives. She mothers most or all offspring within a given hive.
In the field of behavioural ecology polyandry is a type of breeding adaptation in which one female mates with many males. Another opposite breeding system to this is polygyny in which one male mates with many females (e.g., lions, deer, some primates, and many systems where there is an alpha male).
A common example of polyandrous mating can be found in the Field Cricket Gryllus bimaculatus of the invertebrate order Orthoptera (containing crickets, grasshoppers, and groundhoppers). Females in this species will mate with any male close to them, including siblings. Widely shown in frogs (Agile frogs, Rana dalmatina), polyandry was also documented in polecat (Mustela putorius) and other mustelids.
Many reptile species also demonstrate polyandry, especially among members of the tortoise family (Testudinidae). Through polyandry and long-term sperm storage, recent studies have found evidence for the ability of female tortoises to produce clutches of eggs that demonstrate multiple paternity. Predictably, these hatchlings showed an increase in genetic variability compared to those sired by a single male. Potential for multiple paternity within a clutch is primarily a result of sperm storage across reproductive cycles, since studies have confirmed the presence of multiple males’ sperm in the female tortoise reproductive tract simultaneously. As a result of clutches with greater variation in paternal genes and increased sperm competition, females can maximize both the genetic quality and number of offspring. Multiple paternities within a single clutch is therefore considered an effective strategy to increase the reproductive success and fitness of female tortoises.
It is easier to ensure reproductive success (i.e., it is more likely that the female will have offspring)
Females may be encouraging sperm competition between males post-copulation
Multiple sperm lines may confer more variation in traits to female's offspring, this seems to be the case in the honey bee where bees from different sperm lines excel at different roles within a single hive, benefiting the health of the hive as a whole.
Females may receive food offerings from prospective mates inciting copulation
Offspring paternity is unknown and this can be beneficial in encouraging parental care and discouraging infanticide by males
Some New World monkeys, such as Goeldi's Marmoset, have been observed living in polyandrous groups. Although groups may contain more than one female, the dominant female suppresses ovulation in subordinates, causing her to be the only one capable of reproduction. A Goeldi's Marmoset female regularly births more than one offspring, and her eggs are separately fertilized by more than one male. Paternal investment is high among Goeldi's Marmosets, and males often carry infants on their backs even if they are not the father of the infant. It has been suggested that multiple male mates were related, and therefore cooperation in caring for each other's young is adaptive; however, researchers tagged and tracked Goeldi's Marmosets over time, and noticed that unrelated males migrated to new groups to cooperate with nonrelatives as well as with relatives to care for young. It has also been suggested that females select cooperative males, and that the multiple offspring of Goeldi's Marmosets require paternal care for survival.
Current research suggests that polyandry is the dominant social structure in the Callitrichidae subfamily of New World monkeys.
The callitrichidae family includes marmosets and tamarins, two groups of small New World monkeys found in South America. Wild groups usually consist of three to ten individuals, with one reproductively active female, one or more reproductive males, and several nonreproductive helpers that can be either male or female. Interestingly, cooperative polyandry is not the only mating system found in these primates. Polyandrous, monogamous, and polygynous groups can be found within the same population, and a group can even change mating systems, making it the most flexible mating system of any non-human primate. Unlike most primates who typically give birth to single young, twins are the average litter size for tamarins and marmosets. The entire group participates in raising the offspring, sharing the responsibilities of infant carrying, feeding, and grooming. The presence of nonreproductive helpers appears to be the most important factor in determining which mating system is used, as ecological and environmental variability have not been found to have a significant impact. Goldizen (1987) proposed the hypothesis that monogamy in callitrichidae should develop only in groups with nonreproductive helpers to help raise the young, and in the absence of these helpers, both polyandrous males and females would have higher reproductive success than those in lone monogamous pairs. Indeed, in studies of Saguinus fuscicollis, common name saddle-back tamarin, no monogamous lone pairs have ever been seen to attempt a breeding cycle.
The term has gained some currency in sociobiology, where it refers, analogously, to a mating system in which one female forms more or less permanent bonds to more than one male. It can take two different forms. In one, typified by the Northern Jacana and some other ground-living birds, the female takes on much the same role as the male in a polygynous species, holding a large territory within which several males build nests. Subsequently, the female lays eggs in all the nests, and plays little part in parental care. In the other form, typified by the Galápagos Hawk, a group of two or more males (which may or may not be related) and one female collectively care for a single nest. The latter situation more closely resembles typical human fraternal polyandry.
Although polecats are chiefly polygynous, females can show polyandry, and the sexual conflict aspect of the mating system can change with environmental conditions. Sexual conflict may result in sexually antagonistic co-evolution or “sexual conflict”, in which one sex evolves a “manipulative” character which is countered by a “resistance” trait in the other sex.
These two forms reflect different resource situations: polyandry with shared parental care is more likely in very difficult environments, where the efforts of more than two parents are needed to give a reasonable chance of rearing young successfully.
Honeybees are said to be polyandrous because a queen typically mates with multiple males, even though mating is the only interaction that they have (the males die off, while the queen uses stored sperm for eggs she fertilizes). Utetheisa ornatrix also demonstrate a polyandrous mating system, where females mate with multiple males. On average, females mate with four to five males over their lifespan of three to four weeks but can mate with and receive up to thirteen spermatophores. This allows for increased paternal investment through the content of the spermatophores given to females.
Polyandry in primates, mammals and other animals is usually correlated with reduced or reverse sexual dimorphism—females larger than males. When males of a species are much larger than females, polygyny is usually practiced. As size difference decreases, or the females are larger than males, a species is more likely to practice monogamy or polyandry. The great apes (gorillas, orangutans, chimpanzees, and bonobos) are dimorphic, the greatest disparity occurring in gorillas. Chimpanzees and bonobos have promiscuous societies in which the female mates with multiple males and vice versa. Should only a few females come into estrous, the males of the group will mate with only a few females, creating a fluid form polyandry. However, in chimpanzees, should the alpha male be powerful enough, he will discourage the other males from soliciting a female in estrous and vice versa, effectively establishing a loosely maintained form of polygyny. Chimpanzees and bonobos exhibit slight sexual dimorphism, the latter being matriarchal despite the females' smaller size. Gorillas practice true polygyny with one much larger male travelling with several females and their children. He alone will mate with his female companions. Though orangutans are solitary, it has been found that several females will build their nests within an adult male's territory and will mate more often with this one male than with others, thus demonstrating a form of polygyny. Male and female gibbons (lesser apes) are similar in size and form monogamous pairs. Human males and females are less dimorphic in body size than the other great apes, and engage in polyandry, promiscuity, polygyny, and monogamy, the latter two being the most common. Conversely, birds of prey - which show distinct reverse sexual dimorphism—tend to be monogamous for long periods or mate for life; some species like the Snail kite will choose new mates every year, polygyny is noted in many Harriers and polyandry has been observed in the Harris' Hawk (notable for being the only bird of prey to regularly live and hunt in family and social groups) and the aforementioned Galapagos hawk.
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^Chris Arsenault (24 October 2011). "Millions of aborted girls imbalance India". Al Jazeera. Retrieved 29 October 2011. "While prospects for conflict are unclear, other problems including human trafficking, prostitution and polyandry—men (usually relatives) sharing a wife—are certain to get worse."
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