Resident orcas throng in summer

The killer whale or orca (Orcinus orca) is the largest species of the dolphin family and is considered the apex predator of the marine world. Killer whales are found in all the world’s oceans, though they prefer cooler temperate and Polar regions.

Killer whales become mature at 15 years of age. Females breed until the age of 40 and give birth to a single calf about once every five years. Calves nurse for up to two years and are dependent on their mother for the first 10 years of their lives. Calf mortality is high, and some studies indicate nearly half do not survive their first year.

Males typically range from 19-26 feet in length, while females are smaller, ranging from 16-23 feet. Females live for 50 years on average, but they can live up to 70-80 years of age. Males have shorter lifespans with an average of 30 years and maximum of 50-60 years.

In Alaska waters, two types or races of killer whales occur that differ from each other in several respects.

Resident killer whales subsist on fish and are known to visit the same areas consistently. They travel in large pods and form lifelong family bonds. Pods are matrilineal, composed of a female and her offspring. Males leave the pod for short periods to mate outside their maternal group, but otherwise spend their entire lives with their mothers. All pod members, including males, care for the young.

Transient killer whales feed on marine mammals and travel in smaller, less structured pods. Transient and resident killer whales inhabit the same waters but do not intermix.

Offshore killer whales are the third and least understood group. They roam the open ocean and feed primarily on fish, sharks and sea turtles.

There are also three distinct races of killer whales in the Antarctic. Type A killer whales live in open water and feed on minke whales. Type B killer whales inhabit inshore waters and feed mainly on seals. Type C killer whales live mainly in pack ice and feed on fish.

The debate as to whether or not the different types of killer whales comprise separate species is ongoing. Although transients and residents could theoretically interbreed, genetic studies indicate they have not done so for thousands of years. Presently, each race is identified as a distinct ecotype.

Killer whales are highly vocal in communicating with each other. Residents are especially so, and each pod has its own distinct dialect.

Individual killer whales can be identified by noting differences in the dorsal fins or saddle patches. By cataloguing individual killer whales, researchers are better able to trace their movements.

The killer whales we see in Kodiak waters roam the northern Gulf of Alaska waters. In summer, resident killer whales throng to Kodiak in pursuit of salmon, forming megapods of 100 to 150 animals.