Alloparenting

thumb|upright=1.5|[[Vervet monkey with young in Tanzania]]

Alloparenting (or alloparental care) is a term for any form of parental care provided by an individual towards young that are not its own direct offspring. These are often called "non-descendant" young, even though grandchildren can be among them. In species that alloparent, it has been seen that offspring grow at faster rates and are often weaned earlier.

Behavior

The behavior revolving around alloparental care is more or less the same among species. The term "babysitting" is often used as a way to describe how this parental style works. In humans, alloparenting is common and mainly revolves around this term. Other parents and people watch others' young and help care for them while the biological parents are busy. These behaviors allow for the parents to have more freedom while knowing that the young are cared for. Alloparental care itself involves certain behaviors from the individuals partaking in this care. In humans and chimpanzees, this may involve carrying, walking with, cleaning, and physical contact with the young. In other animals such as whales, birds, and Indian free-range dogs, these behaviors may be feeding/regurgitating food, giving warmth, and guarding. In sea lions, behaviors such as allonursing may be seen. Behavior is the center of alloparenting and without parental care, many species' young would not survive.

Allonursing

Allonursing falls under alloparenting. Allonursing is when a female provides nourishment for offspring that is not her own. Allonursing not only benefits the offspring but it also benefits the nurser as well by allowing her to gain maternal experience, and therefore when her offspring is around she will be able to strengthen its survival. In addition, Wilson used the term alloparent (or helper) to refer to the individuals providing the care, and proposed allomaternal and allopaternal as phrases that could be used to distinguish the sex of the helper. "Alloparent" roughly means "other-parent"; from the Greek root "allo-", meaning other.

Alloparenting encapsulates a diverse range of parenting systems and behaviours. Simply, it can be understood as a system of parenting where individuals other than a direct genetic parent act in a parental role, either for a short, or extended period of time. This definition does not exclude alloparents who are blood relatives of the offspring, such as siblings and aunts, who are often observed as 'helpers at the nest'. In such cases, the alloparent and the offspring share a degree of relatedness (r (coefficient of relatedness) > 0); so kin selection is often involved in the evolution of the behaviour. Use of the term non-descendant young, as opposed to non-related young is therefore an important distinction in the definition of alloparenting. The non-descendant young in whom the alloparent invests can be conspecific (of the same species) or heterospecific (of a different species), a phenomenon often observed in fish and a select number of bird species. Though such parasitic relationships, such as what occurs with cuckoo chicks, were not specifically addressed by Edward O. Wilson in his original discussion, adoption and slavery across species in ants was discussed; a relationship which could be described as parasitic for the heterospecific young.

This concept of parental investment applies to the alloparent in the same way that it does to a genetic parent; however, any investment into the production of gametes, which Trivers included in his definition, is not relevant, and is therefore usually restricted to behavioral considerations for the alloparent.

Classification

The forms of alloparental care which occur in nature are numerous and varied and resist classification. Relationships between the alloparent and the young, and the alloparent and the genetic parent, range from cooperative and mutualistic to exploitative and parasitic. The below outline provides one classification for the many forms of alloparenting which have been observed:

'True' (mutualistic)

This form of alloparenting is characterized by interactions/relationships which provide and overall fitness benefit to the alloparent, the young, and the genetic parent. and African wild dogs who share in pup feeding and display 'babysitting' behaviour. Cooperative breeding is often provided as strong evidence in support of kin selection.

• Joint brood care ('babysitting') – Communal care of broods is similar to cooperative breeding, but more commonly involves a number of reproductive pairs or mothers. Sometimes referred to as 'babysitting' or reciprocal cooperation, this system of parenting allows the genetic parents greater foraging freedom, and appears to be supported by the mutual benefits participating individuals acquire through reciprocal altruism. and vampire bats who display reciprocity in food sharing. Babysitting females are frequently observed in primate species, such as the ring-tailed lemur, vervet monkeys, rhesus macaques and langurs.

thumb|right|Brood parasitism: [[Reed warbler feeds a common cuckoo chick.]]

'Misdirected' (parasitic)

Relationships between 'parents' and young that are in some way parasitic, perhaps resulting from reproductive errors or maladaptive behaviour, are an interesting and somewhat hazy form of alloparenting. In some cases, alloparents may find themselves investing in heterospecific young, and gaining none, or very little overall fitness benefit. Though ultimately maladaptive, this sort of behaviour may be supported by an inability of parents to recognize their own young (for example stolen fertilisations in fish), or supernormal stimuli 'enslaving' the alloparent into providing the care, as is seen in the case of brood parasitism of the cuckoo bird. Two well-documented types of parasitic or misdirected alloparenting are:

• Brood parasitism: this is where the genetic parent will leave their young in either the care of a conspecific or heterospecific alloparent who commonly has a brood of their own.
• Cuckoldry: this occurs in many colonially breeding bird species where extra-pair copulations may take place and the males end up caring for unrelated offspring.

Benefits

To the alloparent

Benefits acquired by the alloparent are dependent on the form of alloparental care, but range from:

• Indirect fitness benefits gained via kin selection
• Parental experience: gaining mothering/parental practice through 'babysitting' can increase the likelihood that the alloparents future genetic offspring will survive.
• Increase in social rank
• Extra-pair breeding opportunities/acquisition of mates
• Protection from predation during cooperative breeding or joint brood care.
• 'Agonistic buffering': individuals may enlist the influence of young within a group as protection during aggressive interactions.
• Acquisition of home territory following cooperative breeding
• Increased survival of genetic offspring during joint brood care

To the young

thumb|right|Black-backed jackal pups playing

In almost all forms of alloparenting, the young get an overall fitness benefit from the care provided. In cooperative breeding or joint brood care, the presence of 'helpers' at the nest or den usually increases the young's probability of surviving. This has been observed in a number of species including the black-backed jackal (Canis mesomelas). By helping raise their full siblings, with whom they share a coefficient of relatedness of , the helpers were benefiting from increasing their inclusive fitness.

In cooperative breeding

In cooperative breeding, mothers are able to conserve energy, travel further away from nesting grounds to forage for food/supplies, maintain social interactions, and better protect their offspring from predators. The offspring that experience alloparental care benefit from increased protection from predators, development of social cues, and learning group dynamics through social interactions. The alloparents benefit as they are given the opportunity to gain mothering skills before they have reached reproductive age. The relationships formed through alloparenting have also been seen to enhance the stability of the family, herd, or community over time.

Costs

To the young

In some instances of alloparental care the young are exploited, which may lead to mistreatment by the alloparent. An example of this is when male primates use young for 'agonistic buffering' during confrontations with dominant males. For example, habitat saturation was shown to be responsible for cooperative breeding in the Seychelles warbler, a small passerine bird. It was also observed that remaining at the nest correlated to a higher chance of inheriting the parent's territory. Additional ecological constraints have since been proposed as factors favoring cooperative breeding:

• Reduced survival probability following dispersal
• Reduced probability of finding a mate
• Reduced chance of successful breeding once a territory has been established

As a result, cooperative breeding is often seen in populations where there is:

• High population density
• Intense competition for food, territory and resources
• Stable environment

This has in turn selected for species producing a small number of offspring who require a large amount of parental care.

Alloparenting behavior is known from 120 mammal and 150 bird species. This is seen when male Barbary macaques carry around unrelated infants and care for them for hours at a time. Another example is when warthog sows suckle piglets from other litters after the sows have lost their own litters.

thumb|right|upright=1.3|A mother sperm whale and her calf off the coast of [[Mauritius.]]

'Babysitting' in sperm whales

Sperm whales (Physeter macrocephalus) are deep divers that exhibit alloparental care in the form of 'babysitting'. When the whales are young, they are not able to dive to and remain at the depths that their mothers frequent in order to graze and feed. Yet being left at the surface alone makes them vulnerable to predators like killer whales and sharks. Sperm whale social groups appear to modulate their diving behaviour in order to provide alloparental care to young within the group and reduce the time they spend alone at the surface, at the same time allowing the mother greater foraging freedom. They do this by changing the synchronicity of their dives to limit the time a young whale spends alone. It is through this manipulation that the catfish young gain greater protection from predators. Although placed in a more vulnerable position, the cichlid young still benefit from the interaction; both their genetic and 'allo' parents defend against predators (mutualistic defense), and being a mouth breeding species, this 'farming out' (which frees them from the mouth) may allow the cichlid young to forage more and grow faster. It has also been observed that the bagrid catfish alloparent will allow the cichlid young to feed off the skin on its dorsal surface.. Given the lack of archaeological evidence for cats kept as pets until some 4,000 years before present, intraspecific social behavior including alloparenting was most likely fully evolved before interspecific sociality emerged, but the comparative abundance of resources in and around human settlements increased frequency of the behavior. Alloparenting in particular seems to be related to feline allogrooming and allorubbing. which can result in greater familiarity between individuals. In colonial situations and shared habitats, such familiarity can extend to offspring of individuals. In research published in 1987 on semi-feral farm cats in England, researchers observed that all 12 breeding females that could have nursed each other's offspring did so, and in the majority of cases shared their kittens' nests. As housecats have more opportunities to interact with one another and typically face less competition over resources or range, they display even greater social tolerance towards one another than feral or semi-feral cats, which may result in increased frequency of alloparenting behaviors, In any event, alloparenting amongst cats confers numerous benefits; ranging from protection against predators and potentially infanticidal males, increased health for mothers and offspring, (future) reduction in conflict over resources and territory, information exchange, and so on.

In humans

Alloparenting in humans is a common form of parental care in a variety of cultures and can include care giving from siblings, grandparents, other relatives and unrelated family members such as teachers for providing learning and support. One particular example is a situation in which grandparents adopt a parental role. This is sometimes named a "skipped generation household". In 1997, 8% of children in the United States lived with their grandparents, with the grandparents being the caregivers in one third of those cases. the Efé people of Ituri Forest in the Democratic Republic of Congo practice alloparenting, with care for infants coming from siblings, grandparents, and older members of the community. Deihl states that where siblings are alloparents this provides adolescents experience of being a parent.

Human psychology in alloparenting

The traditional model of child psychology in relation to parents is called, "Classical Attachment" in which the child has a strong attachment to one figure (the mother). In alloparenting communities, attachment theory suggest that the same sort of bond is shared between the child and multiple community members. This has potential advantages for the child and the parents. The child has a diversified network of caregivers which can provide intimate emotional support. The parent's cost of child rearing goes down as well as the emotional cost and cost of tangible resources. According to The US National Library of Medicine, alloparenting has proven to activate portions of the brain that are correlated with decreasing stress levels.

Cause and effects of alloparenting

Cause

Alloparental care has many benefits for the young as well as the biological parents of the young. It occurs when there is a high energetic command of the biological parents and the group living of these animals.