Killer whales, otherwise known as Orcas, are actually the largest members of the dolphin family, and as such are not whales at all. They are the great hunters of the ocean, often being compared to wolves for their hunting ability and desire to remain in a pack, or pod. They are not usually violent creatures but are at the top of the oceanic food chain, having no natural predators. Orcas are also known as the fastest mammal in the ocean, reaching speeds of up to 30 mph if necessary. After being seen hunting whales they became known as 'whale killers'. At some point the name became reversed and they have been known as 'killer whales' ever since.
While most populations of Orcas feed on fish there are some that prey on marine mammals as their primary diet. These whales dine on everything from sea lions to several different types of whales. Orcas are very social, living and hunting in matriarchal packs. Male orcas often spend their entire lives with their mother, only leaving them during mating season but then returning for the rest of the year.
Among Orcas there are three subspecies or populations that determines their diet, their social interactions and the general areas in which they live. Resident Orcas eat primarily fish and squid, have a strong familial bond and spend most of their time in the northeast Pacific ocean. Very little is known about the Offshore Orcas, but their diet appears to be mainly fish, sharks and sea turtles. They travel in large pods and are known to travel in the deep ocean waters. Transient Orcas are the so-called killer whales of lore. These Orcas eat exclusively marine mammals and travel along the Alaska waters in much smaller pods than the other Orcas.
The whales most often preyed upon by transient Orcas are Minke Whales and Gray Whales. They will also occasionally attack a Sperm Whale or Blue Whale but steer clear of a full size male Sperm Whale, as it is the largest mammal on Earth and can easily kill an Orca. They commonly go after young or weak whales, however in a pack of 5 or more they can take down a healthy adult whale. Orcas attack in a group and like to disable their prey before eating it. They will chase a mother and her calf until they are too tired to go on and then separate the mother from her calf. The Orcas will then prevent the calf from surfacing in order to drown it before eating it. Female Sperm Whales will travel in pods and provide a protective circle around their calves in the event of an Orca attack.
Orcas are not a threat to humans, but there are few human attacks on record. In every situation it was a case of mistaken identity where the Orca thought the human was their normal prey, and as a result did not injure the person. Orca attacks on humans are mainly limited to captive Orcas turning on their trainers. Orcas were hunted for their meat, as well as by fishermen who viewed them as competition until 1981 when they became protected by the International Whaling Commission.