Small fish are swallowed whole, head first so that the scales slip easily down the throat. The teeth of the crabeater seal are more specialized, though. They all have deep dents in them and form a sieve for s ifting shrimplike krill out of the water. As a seal dives, it breathes out and closes its nose and ears. Underwater, it uses oxygen stored in its blood.
Seals have more blood for their body size than do land mammals.
Back at the surface, the seal breathes again. While diving, a seal's heart rate slows from about 120 beats per minute to as low as 4-6 beats per minute. Most of the oxygen-rich blood is directed away from the outer parts of its body, like the flippers. It is pumped to the brain and heart, where it is really needed. Bulls, Cows and Pups Male seals are called bulls, and females, cows.