1. Krill are the principal food of the baleen whales, such as the blue whale and minke.

2. The cetaceans are divided into two groups: the baleen whales which have whalebone instead of teeth and the toothed whales.

3. In order to porpoise, baleen whales must reach four times their normal cruising speed - probably beyond their capabilities.

4. But it is easier to hear the baleen whale, with its lower-frequency call, than the beaked whales, says Theriault.

5. Whales are divided into two main groups, toothed whales and baleen whales.

6. Its calls do not match those of any known species, although they are clearly those of a baleen whale, a group that includes blue, fin and humpback whales.

7. Evoking the poster for the original summer blockbuster, a new species of killer sperm whale attacks a baleen whale in an illustration.

8. "When we saw its huge teeth, we knew it couldn't be a baleen whale.

9. One group of whales has, instead of teeth, long strips of bone, hanging from their upper jaw. This is the baleen whale, the largest animal in the world.