The cheek teeth of walruses are capable of crushing tough shells because they are strong and flat.


"The walrus has only 18 teeth in its mouth, but the upper canines form great ivory tusks up to a metre long. It uses them for levering itself on to ice floes, as weapons in battles with other males over females, and as digging tools to extract clams and other invertebrates from the sea bed. A walrus may dive to depths of 200 metres and more in search of food, and is thought to use its tusks to plough up the sediments on the sea bottom to expose shells, which are recognized in these murky depths by the stiff sensory bristles on its snout. Behind the tusks are strong flat teeth capable of crushing the hardest shells." (Foy and Oxford Scientific Films 1982:147)

The grand design: Form and colour in animalsBLA Publishing Limited for J.M.Dent & Sons Ltd, Aldine House, LondonOctober 23, 2016
Sally Foy