About 320 individually identified transient orcas are commonly seen along the coastline of Washington and British Columbia and from Southeast Alaska to California. These transient communities haven't all been photographed. (Photo - courtesy of Harbour Spiel Magazine - Pender Harbour BC)

Transient killer whale pods are generally comprised of an adult female and two or three of her offspring. Among the differences between residents and transients are that while resident orcas of both sexes stay within shouting distance of their mothers their entire lives, only first-born male transients maintain such intense fidelity to their mothers. Optimum pod size for transients is three, so whenever a third offspring is born, one of the siblings often leaves. The rule seems to be that the eldest son can stay, but all but one of the others may have to go.

After departing their mother's company, roving males may join up with other groups from time to time. Females are more likely to join up with other transients, at least for a time. It isn't known if the hosts are relatives. Departing offspring, whether male or female, tend to leave their mother at 5 to 12 years of age.