Allomothering is the nonmaternal raising of young by individuals outside the parental pair bond. In certian primate social groups, often times alloparents will aid in raising the infant. providing food, or protecting infant from predators, ect. This alloparent could be a close relative, non-reproductive male, or a non-reproductive helper.
Maestripieri, D. (1994). Social structure, infant handling, and mothering styles in group-living old world monkeys. International Journal of Primatology, 15(4):531-553.
Benefits of allomothering
Allomothering has been found to be a learning method to becoming a better mother in some primates.
Jane Lancaster hypothesized that learning-to-mother primate females with no children of their own participate in allomothering.
Lynn Fairbanks (1988) found that females without offspring tried to allomother more frequently than what you'd expected based on the group's population, while parous females tried it much less than expected. In a study she conducted on vervets they found that first-time mothers with high alloparenting experience raised 100% of their first offspring to maturity, but mothers with low experience had less than a 50% survival rate of their first infant (Fairbanks, 1988).
In this case allomothering provided the skills for future mothers to successfully raise their young to maturity. Allomothering occurs in other mammal species, particularily elephants. Juvenile elephants help to comfort, assist and protect the calves. Caretaking of the calves helps to strengthen the family bond in the elephant groups (Lee, 1987).
Lee, P. 1987. Allomothering in African Elephants. Animal Behaviour, 35,1,278-291.
Fairbanks, L. (1988). Vervet monkey grandmothers: effects on mother-infant relationships. JSTOR, 104(1/2), 176-188
In humans, living postreproduction is an anomaly other primates don't share. Coall & Hertwig (2010) discussed the hypothesis that granparents are a class of allomothering & promote their reproductive fitness by caring for their grandchildren.
Coall, D. & Hertwig, R. Grandparental investment: past, present, and future. Behavioral and Brain Sciences, 33, 1 -59.
Species that Practice Allomothering
Allomothering, also referred to as cooperative breeding or alloparenting, is practiced in many species. Nine percent of bird species and an estimated three percent of all mammal species, even humans, participate in alloparenting. Some birds that allomother are magpie jays. This behavior is common in about twenty percent of all primates. Vervet monkeys, marmosets, golden lion tamarins, dusky leaf monkeys, lemurs, and langurs, live in social groups and cooperatively take care of young. Great apes (orangutans, gorillas, etc.) tend not to allomother. Young African elephants and dolphins are “raised” by other females in their group as well as their biological mother. Meerkats, wild dogs, and wolves even have subordinate females that go through a pseudo pregnancy and develop milk to feed the dominant female’s offspring. Some bird species also practice allofathering.
Hrdy, S. B. (2009). Meet the alloparents. Natural History, 118(3), 24-29.
Fairbanks, L. A. (1990). Reciprocal benefits of allomothering for female vervet monkeys. Animal Behavior, 40, 553-562.