![Vervet monkey with young](https://upload.wikimedia.org/wikipedia/commons/6/65/Vervet_monkey_with_young.jpg)
Alloparenting (also referred to as alloparental care) is a term used to classify any form of
parental care
Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal k ...
provided by an individual towards young that aren't its own direct offspring. These are often referred to as "non-descendant" young,
even though grandchildren can be among them.
Among humans, alloparenting is often performed by a child's grandparents and older siblings. Individuals providing this care are referred to using the neutral term of alloparent (or "helper").
Alloparental care encapsulates a diverse range of parenting systems across a range of animal groups and social structures. The alloparent–young relationship can be mutualistic or parasitic, and between or within species.
Cooperative breeding
Cooperative breeding is a social system characterized by alloparental care: offspring receive care not only from their parents, but also from additional group members, often called helpers. Cooperative breeding encompasses a wide variety of group ...
, joint brood care, reciprocal allonursing, brood parasitism and cuckoldry represent situations in which alloparenting plays a role.
Alloparenting is a form of parenting that is not found often in the wild.
With this type of care comes some costs, including the spending of time and energy for caring for another's offspring at your own expense with no direct benefits from it.
This form of parenting is seen frequently among the human population. However, it is not as popular among other species. Alloparenting is rare among classes of animals such as birds and mammals, with only about 3% of mammals exhibiting this parenting style, but this does not mean it does not occur.
In species that alloparent, it has been seen that offspring grow at faster rates and are often time 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 seen abundantly and it mainly revolves around this term. Other parents and people watch others young and help care for them while the biological parents are busy.
This is seen in Sperm Whales as well. To allow the mother to dive and gather food and resources, the whales in their social group separate their dives allowing for the baby to be monitored and overseen by a whale during all times.
Superb Starlings also perform this behavior. Their group living situation contributes to many potential parent figures in the young's life. The mother and father may provide the heat and guarding of the nest however it is a network of other superb starlings that also watch over and take care of the offspring as well.
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 an offspring that is not her own.
With alloparenting being rare as is, allonursing is even rarer. One reason for this is because, for a female to allow for the suckling and nursing of young, she too must have had an offspring recently for her to provide the nourishment. In a mother’s milk, different antibodies and immune boosting nutrients can be found. Allonursing helps the offspring receive more immune compounds than those of just its mothers.
Allonursing not only benefits the offspring but it also benefits the nurser as well by allowing them to gain maternal experience and therefore when their offspring is around they will be able to strengthen their survival.
In a study done with cooperative breeders and non-cooperative breeding species, the researchers found that there were fewer cooperative breeding species that allonursed however it was not a significant amount. In noncooperative breeding species, 66% of litter-bearing group living species allonursed compared to 31% of monotocous species.
In both cases, milk composition was not a factor.
In a case study done with sea lions, allonursing can be seen as well. In this study, the researchers recorded an allonursing event when an individual was observed nursing more than one pup at a time and suckling was being performed by a pup or yearling that was confirmed as not her own by tags, brands, or natural marking.
If there was any doubt in this, the event was not concluded. During this study, allonursing was seen twice during the pupping season and more commonly occurred later on.
Primiparous females were seen more often allonursing a pup than multiparous females. Unless the multiparous female was sleeping, oftentimes they would not allow nonfilial pups to suckle and immediately terminate any allosuckling as soon as they noticed the nonfilial pup.
This was different from the primiparous females who allowed for allonursing to continue.
Through these studies, it can be seen that allonursing is not common and for many, it is all based on the specific species and way of life. Although allonursing is beneficial to the offspring in receiving a wider variety of immune compounds, many species do not partake in this event.
Theory
In
biology
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary i ...
,
ethology
Ethology is the scientific study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objectiv ...
and
sociology
Sociology is a social science that focuses on society, human social behavior, patterns of Interpersonal ties, social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of Empirical ...
, alloparental care is defined as any form of
parental care
Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal k ...
, which is directed towards non-descendant young.
It was first used by Edward O. Wilson in 1975, in his book ''Sociobiology'' in an attempt to define a neutral term which could encapsulate the gender and relation specific terms of 'aunite' and 'auncle' which had previously been coined in the literature to describe this sort of behaviour.
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. The word alloparent roughly translates to "other-parent" based on the Greek root "allo", meaning other, and the Latin root "parens", meaning parent.
Alloparenting encapsulates a diverse range of parenting systems and behaviours. Simply, it can be understood as a system of parenting in which individuals other than the direct genetic parents act in a parental role, either for a short, or extended period of time. This definition does not exclude alloparents who are genetically 'related' to the offspring, such as siblings and aunts, who are often observed as 'helpers at the nest'.
In instances where this is the case, the alloparent and the offspring share a degree of relatedness (r
he coefficient of relatedness
He or HE may refer to:
Language
* He (pronoun), an English pronoun
* He (kana), the romanization of the Japanese kana へ
* He (letter), the fifth letter of many Semitic alphabets
* He (Cyrillic), a letter of the Cyrillic script called ''He'' in ...
] > 0), and therefore
kin selection
Kin selection is the evolutionary strategy that favours the reproductive success of an organism's relatives, even when at a cost to the organism's own survival and reproduction. Kin altruism can look like Altruism in animals, altruistic behavio ...
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.
There is some debate as to whether
interspecific
Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species.
Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organis ...
alloparenting (caring for the young of another species) constitutes 'true' alloparental care, particularly when the relationship is
parasitic
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...
for the alloparent, and the care being directed is therefore 'misdirected' or constitutes a maladaptive behaviour.
Though such parasitic relationships, such as what occurs with
cuckoo
Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separ ...
chicks, were not specifically addressed by
Edward O. Wilson
Edward Osborne Wilson (June 10, 1929 – December 26, 2021) was an American biologist, naturalist, entomologist and writer. According to David Attenborough, Wilson was the world's leading expert in his specialty of myrmecology, the study of ...
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 article will consider interspecific and parasitic alloparental behaviours to satisfy the definition of alloparental care.
Alloparental investment
In 1972,
Robert Trivers
Robert Ludlow "Bob" Trivers (; born February 19, 1943) is an American evolutionary biologist and sociobiologist. Trivers proposed the theories of reciprocal altruism (1971), parental investment (1972), facultative sex ratio determination (1973), a ...
defined
parental investment
Parental investment, in evolutionary biology and evolutionary psychology, is any parental expenditure (e.g. time, energy, resources) that benefits offspring.Clutton-Brock, T.H. 1991. ''The Evolution of Parental Care''. Princeton, NJ: Princeton ...
as: "any investment by the parent in an individual offspring that increases the offspring's chance of surviving (and hence reproductive success) at the cost of the parents ability to invest in other offspring" (Trivers, 1972).
This concept of parental investment applies to the alloparent in the same way that it does to the 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.
Possible forms of investment provided by an alloparent can be defined by three of the four classifications of energy expenditure proposed by Crawford and Balon (1996):
* Type II – Preparing for the offspring prior to zygotic development in terms of nest/den building and territory defense.
* Type III – Direct provisioning of food for the young.
* Type IV – Tending to, caring for, feeding, defending and teaching the young.
Given that the alloparent is never the genetic parent, and was therefore not involved in the reproductive behavior/copulation that produced the young, the Type I classification, 'energy investment in gametes', is not relevant when we consider alloparental investment.
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
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...
.
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.
This sort of parental care is often closely tied to social organisation and is thus very common in advanced animal societies such as primates.
It can take on the forms of:
* Cooperative breeding – This system of breeding is characterised by individuals (alloparents) who delay or forego their personal reproduction in order to assist in the reproduction of other individuals within the group, often a dominant breeding pair.
The alloparent 'helpers' are most commonly the siblings of the new offspring, or siblings to the breeding pair. This system is common amongst birds, primates and mammals such as the blackbacked jackal,
and
African wild dogs
The African wild dog (''Lycaon pictus''), also called the painted dog or Cape hunting dog, is a wild canine which is a native species to sub-Saharan Africa. It is the largest wild canine in Africa, and the only extant member of the genus '' Lyc ...
who share in pup feeding and display 'babysitting' behaviour.
Cooperative breeding is often provided as strong evidence in support of kin selection.
Cooperative breeding
Cooperative breeding is a social system characterized by alloparental care: offspring receive care not only from their parents, but also from additional group members, often called helpers. Cooperative breeding encompasses a wide variety of group ...
, particularly in birds, is favored in marginal environments where food is limited or there are high predation rates and it is therefore tough for a breeding pair to successfully raise young on their own.
Newly independent young may also find alloparenting the most successful reproduction option available to them in environments where the resources are scarce or there is habitat saturation. An extreme case of cooperative breeding is what occurs in eusocial insects such as some bee and ant species where a caste system has evolved and workers forgo their personal reproduction to aid in the reproductive success of the colony, gaining indirect fitness benefits through assisting related young.
* 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
In evolutionary biology, reciprocal altruism is a behaviour whereby an organism acts in a manner that temporarily reduces its fitness while increasing another organism's fitness, with the expectation that the other organism will act in a similar m ...
.
Reciprocal altruism involves individuals performing acts to increase the fitness of another individual, in the hope that the act will be reciprocated.
It is not dependent on relatedness, and therefore, babysitting behaviour is often observed amongst non-kin. This form of alloparental care has been observed in reindeer and elk who display reciprocal allonursing and form 'nursery' herds,
and
vampire bats
Vampire bats, species of the subfamily Desmodontinae, are leaf-nosed bats found in Central and South America. Their food source is blood of other animals, a dietary trait called hematophagy. Three extant bat species feed solely on blood: the com ...
who display reciprocity in food sharing.
Babysitting females are frequently observed in primate species, such as the
ring-tailed lemur
The ring-tailed lemur (''Lemur catta'') is a large strepsirrhine primate and the most recognized lemur due to its long, black and white ringed tail. It belongs to Lemuridae, one of five lemur families, and is the only member of the ''Lemur'' ge ...
,
vervet
The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus ''Chlorocebus''. The five distinct ...
monkeys,
rhesus macaques
The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally b ...
and
langurs
The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications spli ...
.
The formation of nursery groups has also been reported in the Atlantic bottle-nose dolphin and
sperm whales
The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the Genus (biology), genus ''Physeter'' and one of three extant species in the s ...
. There are some cases in which brood amalgamation between two species has been observed. In Lake Malawi, cichlid parents are seen to 'farm out' their brood into the brood a potential predator, the ''Bagrus meridionalis'' catfish, and remain to help defend against predators.
Intriguingly, the catfish's care of heterospecific young is mutualistic for all parties.
'Misdirected' (parasitic)
Relationships between 'parents' and young that are in some way parasitic, perhaps resulting from reproductive errors or maladaptive behaviour, constitute an interesting and somewhat hazy form of alloparental care. In some cases, alloparents may find themselves investing in
heterospecific
Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species.
Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organis ...
young, and gaining none, or very little overall fitness benefit. Although ultimately maladaptive, this sort of behaviour may be supported by an inability of parents to recognise 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
Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separ ...
bird.
The genetic parents and the young are not exempt to parasitism and exploitation either. In some species of fish, males exhibit
zygote
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism.
In multicellula ...
stealing, or alloparents may kidnap free-swimming young to help reduce selective pressures on their own brood.
In some cases, alloparents may exploit young in order to receive immediate benefits. In some primate species, low ranking individuals, particularly males, will temporarily care for young in order to increase social status, gain reproductive benefits or use them for 'agonistic buffering', often with little concern for the welfare of the young.
Two well-documented types of parasitic or misdirected alloparenting are:
*
Brood parasitism
Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own ...
: 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
In almost all forms of alloparenting, the young receives an overall fitness benefit from the care provided. In cooperative breeding or joint brood care, the presence of 'helpers' at the nest or den will usually increase the young's probability of surviving. This has been observed in a number of species including the
black-backed jackal
The black-backed jackal (''Lupulella mesomelas),'' also called the silver-backed jackal, is a medium-sized canine native to eastern and southern Africa. These regions are separated by roughly 900 kilometers.
One region includes the southe ...
(''Canis mesomelas'').
In a study of jackal groups in Tanzania spanning three and a half years, it was found that the presence of sibling helpers in the den had a significant positive correlation to offspring survivorship. Through helping feed the mother and her pups, guarding the litter, and contributing to their grooming and learning of how to hunt, each helper in addition to the parents, added 1.5 surviving pups to the litter.
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.
If the alloparents are inexperienced as parents, this could pose as a danger to the young. In some cases of brood amalgamation, young are positioned in a way that subjects them to greater predation risk than the genetic young of the alloparent.
To the alloparent
Alloparenting, given that the behaviour is often initiated by the alloparent, is rarely a costly act for the individual providing the care. Instances where the alloparent receives no benefits, or incurs a cost, generally involve parasitic relationships, where the individual has performed a reproductive mistake, or is misdirecting their parental care.
Evolution
In many discussions of alloparental care, the comment is often made that alloparenting can at first appear
altruistic
Altruism is the principle and moral practice of concern for the welfare and/or happiness of other human beings or animals, resulting in a quality of life both material and spiritual. It is a traditional virtue in many cultures and a core asp ...
.
This appearance stems from the fact that benefits to the alloparent are very rarely immediate, and any fitness benefits gained are indirect. Though alloparenting systems based on reciprocal altruism are well studied, purely altruistic care provided by an alloparent has not been observed. Two of the main evolutionary driving forces of alloparental behaviour are
kin selection
Kin selection is the evolutionary strategy that favours the reproductive success of an organism's relatives, even when at a cost to the organism's own survival and reproduction. Kin altruism can look like Altruism in animals, altruistic behavio ...
and reciprocal altruism.
In cases where the alloparent and young share no degree of relatedness, other benefits to the alloparent will have contributed to the evolution of the behaviour, such as 'mothering-practice' or increased survivorship through association with a group.
The cases where an evolution of such behaviour is most difficult to explain are parasitic relationships such as the
cuckoo chick in the nest of a smaller host parent. Behavioral ecologists have cited supernormal stimuli, reproductive errors, or the inability of alloparents to recognize their young as explanations that may support this behaviour.
In general, the occurrence of alloparental care is the result of both the life history traits of the species (how their evolution has predisposed them to behave), and the ecological conditions in which the individual finds themselves.
Evolution of cooperative breeding
Cooperative breeding constitutes a unique case of alloparenting with a specific evolution. It is a key example of where the evolution has been driven by the combination of life history traits and ecological factors, which act as the triggers.
The first hypothesis put forward for the evolution of cooperative breeding was that a shortage of suitable breeding habitat encouraged young to remain at the nest or territory for a period of time before attempting to raise their own young.
For example, habitat saturation was shown to be responsible for the occurrence of cooperative breeding in the
Seychelles warbler
The Seychelles warbler (''Acrocephalus sechellensis''), also known as Seychelles brush warbler, is a small songbird found on five granitic and corraline islands in the Seychelles. It is a greenish-brown bird with long legs and a long slender bill ...
, 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.
In nature
![Barbary macaque in Cap Carbon (Gouraya National Park)](https://upload.wikimedia.org/wikipedia/commons/7/75/Barbary_macaque_in_Cap_Carbon_%28Gouraya_National_Park%29.jpg)
Cooperative breeding exists in 9% of birds and in 3% of mammals.
Alloparenting behavior is known from 120 mammal and 150 avian species.
"In mammals, care typically encompasses allolactation, pup-feeding, babysitting and carrying young." This is seen when male
Barbary macaque
The Barbary macaque (''Macaca sylvanus''), also known as Barbary ape, is a macaque species native to the Atlas Mountains of Algeria, Libya, Tunisia and Morocco, along with a small introduced population in Gibraltar.
It is the type species of the ...
s carry around unrelated infants and care for them for hours at a time.
["Alloparenting". unt.edu. Texas Registry of Parent Educator Resources; University of North Texas. Retrieved 2005-12-28.] Another example is when
warthog
''Phacochoerus'' is a genus in the family Suidae, commonly known as warthogs (pronounced ''wart-hog''). They are pigs who live in open and semi-open habitats, even in quite arid regions, in sub-Saharan Africa. The two species were formerly cons ...
sows suckle piglets from other litters after the sows have lost their own litters.
'Babysitting' in sperm whales
Sperm whales
The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the Genus (biology), genus ''Physeter'' and one of three extant species in the s ...
(''Physeter macrocephalus'') are deep diving cetaceans 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.
As the 'babysitters' or alloparents dive and resurface the calves swim between them and therefore care is provided by a number of members within the social group.
To observe alloparental care in sperm whales, researchers looked at patterns of diving and surfacing in groups with calves compared to groups without calves.
The calves were observed accompanied by an adult member other than the mother and this allowed the mothers to feed while the calf was protected. The overlapping dive improves the survivability of the calf and benefits the mothers involved with the dive changes.
This form of alloparenting is a learned behavior that occurs under certain circumstances. The neurobiological background in sperm whales has not been deeply observed but coincides with the basis for alloparental care and adolescents learning motherly actions early and the calves gaining the most benefit.
Pilot whales
Alloparental care in
pilot whales
Pilot whales are cetaceans belonging to the genus ''Globicephala''. The two extant species are the long-finned pilot whale (''G. melas'') and the short-finned pilot whale (''G. macrorhynchus''). The two are not readily distinguishable at sea, ...
is observed in both direct and indirect forms. Babysitting is a form of direct care while shelter construction and maintenance are indirect care. The pilot whales had observed care through escorting from a non-biological member of the group.
The results show that most pilot whale calves were accompanied by an escort as newborns and young calves.
This study discovered that alloparental was occurring at the group level and not at the unit level. The companions providing the care were more often males than females; which is different from many of the other species listed. In other species, the males teach the social norms and behavior in group-living which explains the male companions.
Reciprocal altruism is the expected return of behavior in the future and this is an explanation for this escorting behavior. By escorting the young of another parent, the alloparent can expect the same to happen with their young. Pilot whales demonstrate alloparental care in the form of escorting and this has limited cost to the alloparent through reciprocal altruism.
Interspecific brood amalgamation
In
Lake Malawi
Lake Malawi, also known as Lake Nyasa in Tanzania and Lago Niassa in Mozambique, is an African Great Lake and the southernmost lake in the East African Rift system, located between Malawi, Mozambique and Tanzania.
It is the fifth largest fre ...
, it has been observed that a select few species of cichlids will 'farm out' their young into catfish (''
Bagrus meridionalis
The kampango or kampoyo (''Bagrus meridionalis'') is a critically endangered species of large and predatory bagrid catfish that is endemic to Lake Malawi, Lake Malombe and the upper Shire River in Africa. It prefers areas near rocks in water sha ...
'') broods, a larger predatory fish.
In many cases the cichlid parent will remain close by to participate in mutualistic defense of the young. In a study by Mckaye et al. (1985), 50% of observed catfish broods contained cichlid young; with the catfish offspring in these broods having six times greater survivorship.
This increased survivorship of the alloparent's young has been linked to the dilution effect, and the way that the geometry of the interspecific school is manipulated such that the cichlid young are forced to the periphery, where they are more vulnerable to predation.
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.
This case of interspecific brood care, which in some cases results in full adoption, is unique in that it is uncommon to see care of heterospecifics where the relationship is mutualistic for all parties.
Chimpanzees
Alloparental care was observed and studied in Chimpanzees. Alloparenting was a huge part of a successful twin chimpanzee’s upbringing. The mother of the twins observed was Sango and they observed the parental care of these babies starting at 2 years old.
In chimpanzees, there are four kinds of parenting behavior: walking together, infant carriage, grooming, and physical contact.
The male twin, who was named Daiya, spent most of the time raised by Sango, his mother. Along with her care, his father Robin spent an abundance of time expressing physical contact with him and very little grooming.
He also was seen walking with him often. The other chimpanzee females in the enclosure did not focus on Daiya much. Koyuki and Cherry provided a lot of physical contact with the toddler and were seen walking with him scarcely. Chelsea, another female who helped nurture him, walked with him and provided physical contact along with minimal grooming.
Judy, the last female in the enclosure barely helped nurture him, she only showed physical contact a few times. The care for the female twin, Sakura, differed greatly between the fully grown adult chimpanzees.
Rather than Sango providing the most care for her own young, Cherry was seen with her the most. Although Sango did provide all four parenting behaviors, she provided little grooming and walking compared to what she provided for Daiya. Like Sango, Robin provided much less care for the female twin compared to the male twin.
In Sakura’s case, a lot more alloparenting was observed. Cherry provided all four parenting behaviors for Sakura and so did Koyuki.
Chelsea provided three out of the four parenting types and instead of grooming as she did with Daiya, she was seen carrying Sakura instead. Judy was not present as much in Sakura’s upbringing just as seen with Daiya, however, she was spotted walking with her on occasion.
Indian Free-Range Dogs
Alloparenting is observed in Indian free-range dogs as they roam the streets of India. In this study, the researchers spent their time following one dog known as ML during the first season and her daughter PW, during the second.
They found that ML spent roughly 18.05% of her time with her pups. Of this 18.05%, 5.55% of that was spent actively parenting.
Over time as the pups grew up and got more independent ML spent less time with them. For PW, she spent 65% of her time with her pups which 84.6% of that was spent actively parenting.
For PW, her mother ML helped parent two of her pups. This occurred in the second year when ML did not give birth to any litter herself. ML showed all the behaviors of actual parenting. She helped groom, provide food, play, and protect the pups however she did not allow them to suckle.
ML spent a significantly higher amount of time and effort guarding than she did with any other active parental care behaviors when alloparenting.
When ML was alloparenting her grandchildren, the amount of time spent with them did not decrease as it did for her pups. Instead, she spent the same amount of time with them. She did not show any bias towards them and cared for each pup equally. Although there was no decrease in her time spent, her time alloparenting overall was less than what both her and PW spent with their kin.
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.
According to Deihl, the
Efé people of
Ituri Forest
The Ituri Rainforest is a rainforest located in the Ituri Province of northeastern Democratic Republic of the Congo. The forest's name derives from the nearby Ituri River which flows through the rainforest, connecting firstly to the Aruwimi Rive ...
in the
Democratic Republic of Congo
The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
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
Developmental psychology is the scientific study of how and why humans grow, change, and adapt across the course of their lives. Originally concerned with infants and children, the field has expanded to include adolescence, adult development ...
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
Attachment theory is a psychological, evolutionary and ethological theory concerning relationships between humans. The most important tenet is that young children need to develop a relationship with at least one primary caregiver for normal ...
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.
Alloparenting helps to reduce the stresses on these animals and reduce the overall energetic demands of having offspring.
The evolution of alloparenting came to rise by the rise of language which leads to cooperation, intelligence, and complex social interactions.
There is an observed correlation between brain size and alloparental care by non-mothers. Oxytocin is an important hormone involved in maternal behavior. A study on voles found that the expression of oxytocin receptors proportionally affects the alloparental behavior in adult female voles.
Prolactin was researched because, in biparental marmoset, the cortisol levels were higher in males than no parent males.
However, there are many hypotheses about the role prolactin, cortisol, and another hypothalamic pituitary axis has on male alloparental behavior, however, there is still more research on the exact roles. There are many hormones involved in parental care and these are leads to the causes of alloparental care.
Effect
Providing alloparental care has many effects on both the receiver of the care and the recipient.
A historian named Stephanie Coontz said human children “do best in societies where childrearing is considered too important to be left entirely to parents.”
This implies that in terms of humans alloparenting has a positive effect on the child. Receiving care from a variety of caregivers gives children the opportunity to learn from many and receive love in different ways.
Introducing a child to this environment allows them to adapt and learn to love and trust widely which will be beneficial in their future adolescent and adult years when they have to leave the comfort of home.
Providing alloparental care comes at a cost to the provider of the care and there are acute and long-term effects that the provider experiences. Prairie voles exposed to pups for 3 hours results in an increase of c-Fos expression in the brain region activated by maternal behavior and c-Fos was in oxytocin neural activation.
Male voles put under stressful experiences increased huddling, licking, and grooming of unrelated pups.
This shows that for males alloparental care could come as a form of stress relief. There is also an observed increase in cardiovascular activity, with a constant increase of heart rate when alloparents are around pups and this is related to the alloparent providing more heat to the pup.
One consequence of alloparental care in a study done on prairie voles is that adolescents exposed to pups showed a decrease in parental care to biological pups.
Other long-term consequences include increased competitiveness, heightened anxiety, and association with reproductive suppression. In a study done on primates, it was found that alloparenting has a positive correlation with infant development.
However, this could lead to malnutrition because mothers must provide more nutrients to keep up with the faster growth and development. Alloparental care is complex and has long-term and acute effects on the animal providing the behavior.
References
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