When you look at most whale's mouths, you may think that you're looking at some kind of odd teeth. What you are really looking at is a series of fibrous plates that hang from each side of the upper jaw, forming a comb-like structure. The interior of this structure is hair like and is the ultimate filtering device in this highly complex animal.
When gray whales feed, they feed on the bottom of the ocean. Rolling on their side with their mouth parallel to the ocean floor, they pull their huge tongues back into the back of their mouths pulling huge amounts of mud and everything in the mud. Amphipods, an animal that lives in the mud, are what they are after. The baleen filters out the adult amphipods and all of the mud and sand are expelled. The baleen are spaced so that juvenile amphipods are released back to the water. Because the adult competition has been removed the juveniles grow at an incredible rate, catalyzed by the nutrients stirred up by the whales.
Geologic studies have shown that the gray whale's activity also benefits the ocean, separating mud from sand; so the mud does not choke out the area but is carried away by currents. 16,000 gray whales and 200,000 walruses which carry on a similar activity are vital to the ecology of the Bering shelf. The intricacy of the design of the baleen and the gray whales' role in the ecology of a huge area of ocean speak of wisdom and design. Our knowledge of the sea is far less than what we know of the land, but as more and more is learned we see complexity that defies chance explanations.