Toothed Teeth Make Seals Successful
Customised teeth make it easy for crabeater seals to munch food. Hundreds of indentations in their teeth have helped them flourish in Antarctica.
The waters around Antarctica are the home of the world’s most numerous seal species, the crabeater seal, which does not eat crabs, rather it specialises in consuming krill.
Krill are rarely more than 1-2 cm long, so it is not energy- efficient to catch them one at a time for seals that grow up to 2.5 m long and weigh 200+ kg. To take advantage of all the small portions of food, the crabeater seal has developed special molars, which have more than 100 tiny indentations that function like the holes of a strainer. When a crabeater seal is searching for food, it swims with its mouth wide open into a group of krill, closes the mouth, and forces the water out through the many molar indentations. Subsequently, it consumes the krill which was trapped inside its mouth.
The seal’s teeth function like a strainer, which lets water escape, but traps the krill. DOUG ALLAN/NATUREPL & CHRIS AND TILDE STUART/ FLPA/MINDEN PICTURES
The teeth are designed to be close fitting at the front and sideways. The seal's molars include more than 100 small indentations. The back of the mouth is sealed off by a protruding bone, making it a closed strainer.