Like other whales, the killer whale is a warm-blooded, air-breathing mammal. They are called "killers" because they prey on fish, dolphins, seals and even larger whales. There are no records of them ever attacking humans. Orca is another name for killer whale.
Killer whales are top-level marine carnivores and opportunistic feeders. Their diet varies depending on the prey available locally as well as on the season. Each whale needs to consume about 4% of is body weight each day, so a reliable, abundant prey-base is essential, and each pod's movement is related to the movement of the food supply.
Orcas travel and hunt in social groups (called pods) of 3 to 40 whales, and sometimes up to 100. They swim in most of the world's oceans, but are most common in cool to cold water.
Adult males are recognized by their tall, triangular dorsal fin, females and immature males by a smaller, curved fin. Large bulls can attain a length of more than 9 m (30 ft.) and a weight of up to 7 t (8 tn.).