Odobenus rosmarus

A walrus’s tusks can grow up to 3ft (1m) long. They are used against predators, to establish dominance, to cut holes in the sea ice and to help heave the walrus’ enormous bulk out of the water. When I say enormous, I mean enormous – a walrus calf weighs about 14 stone (89kg) at birth, with adult walruses reaching weights of around 1.5 tons.