Why do walruses have tusks?

Answer: Defense, dominance, ice climbing

Tusks regulate temperature — Wrong. Tusks do not regulate temperature; blubber and blood flow handle that. The tusks are used for mechanical tasks such as climbing onto ice, fighting, defense, and dominance displays.

Defense, dominance, ice climbing ✓ — Correct! Walrus tusks are elongated canines that both sexes have, and they serve several mechanical purposes. The animals hook their tusks into the ice to haul themselves out of the water, and they also use them to break breathing holes in the ice. Males fight with their tusks for access to mates, and larger tusks tend to mean higher social status. The tusks also help defend against polar bears. They can grow up to three feet long, and because walruses are suction feeders, the tusks are not needed for eating. The family name Odobenidae means 'those who walk with teeth,' which reflects how they use their tusks to move on ice.

Storing calcium for health — Wrong. Tusks are not calcium storage; they are functional tools. Walruses use them for hauling onto ice, fighting, defense, and establishing dominance.