Kin selection

Belding's ground squirrels live underground in colonies where adult females are closely related (kin).

A squirrel may give a loud call to alarm its nest mates when it sees a predator.

Making alarm calls is dangerous: about half the time the caller is killed by the predator, but this may save its kin.

Close relatives share many genes, so kin selection may explain such altruistic behavior:

ground squirrel alarm call