Among cooperatively breeding birds, pairs with helpers fledge about one and a half times more young than pairs without helpers, and the helpers are typically related to the breeding pair. A review of cooperative breeding in birds says kin selection has undoubtedly played a central role in how this behavior evolved, and cooperative breeding is a common strategy in dry regions of Africa and Australia. Naked mole-rats are eusocial: a colony has a queen, a few breeding males and non-breeding workers who care for the young and protect the colony. A honeybee colony has one reproductive female, the queen, and her offspring, while the workers that care for the young are the queen's sterile daughters.

Florida scrub-jays are one of the few animal groups where scientists have found a clear benefit to the breeding parents from having helpers. Their young typically stay in the territory where they were born for at least a year, living as a family group with their parents. Many spend their first several years as helpers. Helper scrub-jays defend the territory and bring food to the young, but they do not sit on the eggs. The Archbold Biological Station study keeps monthly counts of groups, group makeup, parentage and family trees for over 6000 individuals, as of November 2026.

In Yellowstone, wolf packs are most commonly a breeding pair and their offspring from several years. Older wolf siblings also take part in pup care and feeding, and kin selection is probably the best explanation. Pups there are generally weaned at 5 to 9 weeks old and then fed by various pack members through meat regurgitation. The positive influence of helpers was strongest for small packs. Unrelated wolves may also join a pack, so a pack is not always all relatives.

Researchers with the Kalahari Meerkat Project have followed one meerkat group for around thirty years, as of November 2026. In a meerkat group, one dominant female monopolises reproduction, and the other group members help raise her pups. When she dies, the oldest subordinate female, normally one of her daughters, takes her place. Meerkats do not have to be related to belong to the same group. Helpers babysit pups for a day at a time and bring them food until the pups are three months old, and they take turns, because a babysitter cannot eat while on duty and goes a whole day without food.

Vampire bats share blood meals with relatives and non-relatives alike. A study of vampire bats recorded food sharing from 2010 to 2014 and also made individual bats fast for 24 hours to see who would feed them. In the study, bats that were more generous were fed more when they failed to find food. A vampire bat that misses two nightly meals in a row will starve, which is why sharing is like an insurance policy.

Scientists studying resident killer whales found that post-menopausal grandmothers improve the chances of survival for their grand-calves. The orca grandmother study suggests that grandmothers who are still breeding cannot give the same support as grandmothers who no longer breed. Orcas teach younger pod members through apprenticeship, and skills in hunting and parenting are among the skills taught. An orca pod's dialect has been shown to stay the same in a pod for up to six generations. Dolphins recognize relatives by their whistles, and these sounds help keep a group together. An orca calf may nurse for up to two years, and mothers give birth to one baby at a time.

Jane Goodall started the Gombe chimpanzee study in 1960, and it is described as the longest-running study of wild chimpanzees as of November 2026. The Gombe studies have followed generations of chimpanzee families. Tanzanian field assistants record extremely detailed observations on paper, and the same methods continue today. If a young chimpanzee's mother dies, older siblings will often take over the care of a younger sibling. Researchers in Taï forest reported 18 cases of orphaned chimpanzees being adopted by group members. Half were adopted by males, and only one of those proved to be the father. Adoptions by adult chimpanzees can last for years and involve extensive care for the orphans.

Cubs born in a lion pride are twice as likely to survive as cubs born to a lioness on her own. Related females tend to have cubs at about the same time and nurse each other's cubs, and cub deaths are lowest when they do. In an African wild dog pack, once pups leave the den they become the responsibility of the whole pack, and pups nurse from other females as well as their mother. Dolphins help sick, hurt or young group members by taking turns pushing them to the surface to breathe. Lion cubs are often raised in crèches, where the whole pride helps raise several litters.

Words to know

• cooperatively: by working together
• eusocial: fully cooperative
• subordinate: lower-ranking
• apprenticeship: learning from experts
• fledge: learn to fly