Why are baleen whales different from toothed whales?

Baleen whales are in the same family as their cousins the toothed whales, but they have baleens instead of teeth. Hundreds of long baleen plates grow down on either side from the roof of their mouths. Popularly called ‘whalebones’, baleens are actually flexible strips of keratin, the same substance that is found in human hair and fingernails. The baleen plates are edged with hairy fibres that create a sieve to strain prey like knit, plankton, and other small organisms from water.
The whale takes a mouthful of water containing its prey, closes its mouth, and forces the water out between the baleen plates with its tonge. The food is trapped and swallowed. Unlike teeth, baleen continues to grow throughout a whale’s life, as the ends are always wearing out.

Another difference between these two kinds’ whales is that baleen whales are generally large animals. They are not predators. This means that they do not go hunting for the food. In contrast, toothed whales are active predators, usually moving in pods to find prey, which they grasp with their teeth and swallow whole.