This quickness and agility in the water enable orcas to catch almost any prey they want. And when it’s feeding time, they look for animals that are sometimes even larger than they are. Orcas will eat sea lions, sharks, fish, squid, seabirds, and whales. They also 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.