Toothed Teeth Make Seals Suc­cess­ful

Science Illustrated - - ANTARCTICA -

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.

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