A killer whale is technically a dolphin. The fact that it is larger than any of its distant cousins as well as the distinctive jet black and white markings and the tall fin on its back, are the easiest means of identification. The color markings vary slightly among groups throughout the world. Those differences exist even among the various groups within small areas such as Puget Sound. More research has been done on killer whales in Puget Sound than in any other area in the world.
Orcas have a very evolved social structure.
The family unit is the pod, which consists of as few as one or as many as 50 members. The number in an individual pod and its way of life depends on whether it is made up of transient or resident whales. Transient orcas tend to roam over large areas in pods of one to seven whales, stay underwater longer and include marine animals such as seals, sea lions and other whales in their diets. Killer whales have shown a remarkable ability to adapt to changes. Orcas in captivity have been trained to perform acrobatic feats on command and, despite their reputation as fierce and unrelenting hunters, have shown gentle and sensitive sides in their relationships with humans.