Animals That Live in Complex Societies

Food, babysitting, and lookout duty can fall to different meerkats in the same group. Helpers feed pups once they join the foraging group, and individuals take turns watching from raised spots. In one field experiment, well-fed meerkats stood guard more often, suggesting who has eaten can affect who watches next.

Young spotted hyenas usually acquire a rank just below their mother’s. Her relatives and allies can back them in disputes with other youngsters. Several female family lines may share a clan, and their rank relationships hold even though clan members spend much of their time in smaller groups.

A naked mole-rat colony usually has one breeding female and a small number of breeding males. Other members dig, bring back food, or help raise young. Researchers found that body size and other individual traits alone do a poor job of predicting which of those tasks a particular mole-rat takes on.

Female African savanna elephants and their young live in extended families led by a matriarch. When researchers in Amboseli played lion roars to families, those with older matriarchs were more sensitive to the particular danger posed by male lions. The experience of one elephant can shape how her family responds.

Female bonobos can gain leverage by joining forces. In a close analysis of five wild communities, females ranked higher relative to males when they formed coalitions more often. They frequently directed those coalitions against males, but the degree of female influence varied across communities and over time.

In the fish-eating resident killer whales of the Pacific Northwest, sons and daughters can stay with their mother throughout her life. In long-term records of northern and southern residents, calves and older descendants faced higher mortality shortly after losing a grandmother. The association was strongest for grandmothers past breeding age.

Young worker bees usually tend brood and do other work inside the hive, while older workers are more likely to forage. Those roles can change with the colony’s needs. In experiments with the age mix of colonies, some older foragers took up brood care again.

This leafcutter ant divides even garbage duty into distinct jobs. Researchers in Panama watched some workers carry waste away from the nest while others worked on the outdoor dump itself. The dump workers rarely left the heap, keeping their work apart from the foraging activity that supplies the colony’s fungus garden.

A bat that fed can share part of its meal with a roost mate that went hungry. In one captive study with familiar individuals, a bat was more likely to feed a particular roost mate if it had received food from that bat before. Previous sharing predicted donations better than kinship in that experiment.

This Lake Tanganyika cichlid typically lives with a dominant breeding pair and smaller helpers. Helpers can defend the breeding site, clean the eggs, or fan water over them. Some mature fish remain at the territory to help, where they have a chance of inheriting a breeding position.

Inside a reef sponge, a colony of these snapping shrimp can contain hundreds of individuals and one breeding female. She carries her eggs beneath her abdomen. Other members defend the sponge against intruders, protecting the shared shelter in which several generations can live together.

In a colony of this fungus-growing termite, the queen and king reproduce, soldiers help defend the nest, and workers maintain the fungus garden. Older workers bring in dead plant material. Younger ones process it into fresh comb, the surface on which the colony’s food fungus grows.

More than one female can lay eggs in the same nest cavity, while young from earlier years can remain with the group as helpers. The birds help care for nestlings and defend the territory together. Long-running work in California documented these shared nests within family groups that can also have several breeding males.