Although they are called killer whales, orcas belong to the dolphin family Delphinidae. But, orcas eat other species of dolphins.
Orcas have a distinctive appearance, a large black body, a white underside, a white patch above and behind the eye, ‘saddle patch’ behind the dorsal fin. Despite being called killer whales, orcas actually belong to the dolphin family Delphinidae. They’re the only species in their genus, but their closest relatives are dolphin species from around Australia and South East Asia like the Irrawaddy dolphin.
The Latin name for orca or killer whale is Orcinus orca. Orcinus translates to “of the kingdom of the dead” and is probably derived from Roman God of the underworld Orcus, a reference to the fierce hunting reputation of this animal.
A newborn baby orca weighs as much as a motorbike at about 180kg, and they’re 2-3m long. An adult male can weigh about 8600kg and grow up to 10m in length, while an adult female can weigh about 5400kg and grow up to 9m in length.
Orcas will eat other species of dolphins, although they’re harder to catch than some other prey because they can swim so quickly. In a high-speed chase, it’s not easy for a killer whale to open its mouth due to the drag it would cause on its lower jaw, so orcas will typically ram dolphins to stun them before going in for the kill.
Thanks to their large size and huge power, orcas are very fast swimmers and have been recorded at speeds of up to 54km/h (33mph).