Orcas - also know as killer whales - have a diverse diet that includes many types of fish, sea birds, marine mammals and turtles. Now, a new study by Dr. Lisa Ballance from the NOAA Southwest Fisheries Science Center in La Jolla, California, confirms a previous assumption that orcas also hunt other whales - including the much larger humpback. As humpbacks migrates up the west coast of Australia, the orcas are waiting in packs to attack and kill the new-born humpback calves. But in a violent fight that includes splashing, slapping the water with its tail, together with an alarming bellow type sound, male humpbacks assist the females in an aggressive attempt to drive the orcas away. The humpback calf is often successfully protected by the male, but when separated from the female by the orcas, the result is a quick and easy predation.

- Paper in Marine Mammal Science
- BBC story