In all mammals, the bond between mother and daughter is tight at birth, with the infant staying close to her parent for support and comfort as well as for milk. As the youngster grows, however, she becomes increasingly independent. This shift has been documented for Soay sheep living on the Scottish island of St. Kilda (Clutton-Brock et al., 2004). They are free-ranging and thought to be intermediate in type between wild sheep and domestic sheep; the latter have had their social instincts bred out of them to some extent so that they will perceive a shepherd as their leader rather than an elderly ewe (Darling, 1969). Although they seldom interact with their mother, Soay juvenile and yearling daughters usually graze within 20 meters (22 yd) of her as their mutual bond weakens (Clutton-Brock et al., 2004). (The bond between mother and son dissolves much faster, with the lamb on his own by six months of age.) By the time the daughter is about two years old, this friendship is gone, too. She is no more likely to associate with her mother than with any other female in their group. From a human point of view, it is nice to know that the mother likely will, by that time, have another young offspring at heel.

In other species such as those described as follows (chimpanzees, gorillas, baboons, Japanese monkeys, and ring-tailed lemurs), some daughters remain close to their mothers when they reach maturity, continuing to interact with her in a variety of ways. These species are all primates. Presumably other species have close mother–adult daughter ties, too, but research has not focused on this possibility.