Fewest teeth for a seal

The species of seal with the fewest teeth is the walrus Odobenus rosmarus, which normally has only 18 teeth, whereas other seal species generally have 30–36 teeth. Some walrus specimens have additional rudimentary teeth, but these are of only relatively rare occurrence. The typical walrus dental complement consists of a single pair of upper incisors, no lower incisors, a single pair of greatly enlarged upper canines (its tusks), a single pair of lower canines, three pairs of upper premolars and three pairs of lower premolars, with no upper or lower molars present.

In the walrus, its greatly enlarged canines – tusks – grow continuously throughout its life in both sexes, but are longer and heavier in males than in females. In contrast, its other teeth are all very small, simple, and peg-like in structure. The tusks are surrounded by a broad mat of whiskers (vibrissae), up to 70 in number, which are attached to muscles and are well-supplied with nerves and blood vessels, serving as highly sensitive tactile organs able to gauge very accurately the size of anything with which they make contact.