The killer whale, also known as the orca, isn't actually a whale; it's the largest member of the dolphin family. Like dolphins, orcas determine their surroundings by echolocation, which means bouncing sound off objects. They can even stun their prey using high-pitched clicks. Orcas feed on birds, fish, squid and other marine mammals, and sometimes work together to catch a meal, forcing fish into an area where they can be captured, or chasing a penguin into shallow water where other orcas lie in wait. These animals are speedy in the water, able to swim more than 56 kilometers (35 miles) per hour.
Orcas also resemble dolphins in that they're highly social. They cohabitate in pods that range in number from five to 30 individuals. They have a complex type of communication, much like a dialect, that allows them to distinguish one pod from another. The pods are led by the females in highly established hierarchies.