Orcas are called killer whales. The name came from whalers. But the orca is the largest member of the dolphin family. It is mostly black on top, with a white belly and a white patch near each eye.

Male orcas usually grow to 20 to 26 feet (6 to 8 meters) long. Females are smaller, usually 18 to 22 feet (6 to 7 meters). A grown male usually weighs 12,000 pounds (5,400 kilograms) or more. As of November 2026, the biggest orca on record weighed more than 20,000 pounds (9,000 kilograms).

A matriline is a mother orca with her sons and daughters and her daughters' calves. These families form pods. A pod is made up of a few to 20 or more whales that are related to each other. In resident orca families, grown sons and daughters stay with their mother for life. Older female orcas teach younger whales how and where to fish.

Orcas have the most varied diet of all the whales and dolphins. But each group of orcas usually specializes in a few foods. Resident orcas eat fish, mainly salmon, and Bigg's orcas, also called transient orcas, mostly eat marine mammals. Young orcas learn how to hunt from older ones, so orcas in different places eat different foods.

Orcas hunt together as a team. Some herd schools of fish into a tight ball so the fish are easier to catch. Orcas that hunt herring in Norway also slap their tails to stun the fish. Some orcas near Antarctica work together to make waves that wash seals off ice floes. Orcas move to where the food is instead of following a fixed seasonal route.

Orcas use sound to find food, talk to each other and find their way in the water. They click and listen for the echoes. An orca hears through its lower jaw, and the sound travels on to the bones of its ear. Orca echolocation can build a detailed picture of the surroundings, and orcas can even tell fish species apart this way.

Orcas live in every ocean in the world, in cold seas near the poles and also in warm tropical seas. As of November 2026, scientists estimate there are around 50,000 orcas in the world. In the Southern Ocean, the biggest group of orcas, about 25,000 to 27,000, lives around Antarctica.

As of November 2026, the IUCN Red List says there is too little data to say whether orcas as a whole are at risk. The Southern Resident orcas have been listed as endangered in the United States since 2005. Threats to orcas include less food, chemical pollution, and noise and disturbance from boats.

A mother orca has one calf at a time. She is pregnant for 15 to 18 months. Female orcas live about 50 years in the wild, and some live to at least 90. Male orcas live about 30 years on average, and some reach at least 60.

Words to know

• matriline: a mother's family
• pod: an orca family
• herd: gather together
• echolocation: echo finding