The Orca

The orca is one of the most powerful apex predators in the world. The size of a school bus and weighing up to 6 tons, this creature’s size allows it to dominate the ocean and prey on marine animals, large and small. Contrary to their name however, these “killer whales” are not whales. Killer whales, or orcas, are the largest species of dolphin in the ocean. Whale or dolphin, orcas are known for their size and tenacity when hunting—preying creatively on just about anything.

Orcas are found throughout the ocean, from polar regions to the Equator. Typically though, orcas favor cold, coastal waters. Orcas’ diets vary, consisting of seals, sea lions, fish, squids, seabirds, and even other whales. What enables such a large scope of predation is their means of hunting. Orcas hunt in pods of up to 40 members. There are distinctive behavioral differences to be observed between two types of orca pods, transient and resident, that affect what and how they hunt.

Resident pods are most often found in the waters of British Columbia and Washington. These pods remain in one area to live and hunt. Transient pods are nomadic, ranging throughout the Ocean. Along with a difference in ecological location, these pods also differ anatomically. Transient killer whales are a meter or so longer on average and lack much of the pigmentation that resident pod individuals have. This can be seen in the “saddle” region, located behind the top dorsal fin. Transient orcas also have longer, more pointed dorsal fins which make them easier to distinguish. Because of their roving lifestyle, transient orcas feed on marine mammals far more than the fish-eating resident orcas. Their larger size can be attributed to necessity when hunting sea lions, porpoises, and small whales.

In terms of behavior and socialization, these types of orcas also differ. Resident orcas tend to live in larger pods than transient orcas. Based off of closely related matrilines, pods can form clans with other pods of similar dialects and common maternal heritage. As the social structure increases in level, the bond becomes looser. At its base level, matrilines, the orcas maintain a very tight community—leaving only for hours at a time. Transient pods consist of usually one small matriline. These mother-offspring groups roam the ocean together, but it is not uncommon for permanent separation of a member. Some male orcas are known as “rovers” and only join pods temporarily for mating, spending the rest of their time alone. In terms of socialization, resident orcas are far more communicative. Hunting only fish, resident orcas will communicate through vocalizations and echolocation. Fish cannot hear the sounds emitted by their pursuers and are thus oblivious to the oncoming attack. Resident orcas will also celebrate when coming together as a larger group, breaching the water and slapping tails. Transient orcas are very different. Hunting mammals, which can hear the clicks and whistles of the pod, transient orcas remain silent for much of their travel—not wanting to be heard by their prey.

Across the two types, hunting techniques are creative and well executed. Hunting like a wolf pack, orcas have been known to target prey as a group, make waves to wash seals off of ice floes, and even launch themselves on land to reach sea lion pups and scare others into the water.

Despite the controversy surrounding aquariums and exhibits like Sea World, orcas have never been extensively hunted by humans. The treatment of these intelligent giants has been drawn to question when looking at organizations such as these. The morality of keeping animals used to such large habitats in tiny enclosures is something that has been in recent debate for quite some time.  I hope that, after reading this article, you are more aware of just how unique this animal is and better understand the ethical debate against their captivity.