The tusks of a walrus are tools that have social and mechanical functions.

References

“Large tusks (upper canines) occur in both sexes and are used in defence against predators, for breaking through ice, in intraspecific strife, for hooking over the edge of ice for stability while sleeping in the water, and as aids to hauling out and locomotion on ice (Belopolsky 1939; Burns 1965; Chapskii 1936; Collins 1940; Fay, unpublished data; Loughrey 1959; Nikulin 1941,1947; Ognev 1935; Pedersen 1962). It is widely believed that tusks function most importantly in feeding, by digging food out of the sea floor. Detailed studies of feeding ecology and functional anatomy dispel this notion, and suggest that walrus tusks have evolved chiefly for social communication.” (Miller 1975:590)

Journal article
Walrus ethology. I. The social role of tusks and applications of multidimensional scalingCanadian Journal of Zoology, 53(5): 590-613May 1, 1975
Miller EH

“The primary role of the tusks probably is a social one…The walrus’ use of its tusks in threat displays (Frontispiece) was formally reported first by Loughrey (1959:48), who observed that an animal with very large tusks can intimidate others “to move out of its way simply by threatening them,” whereas one with smaller tusks is met with active opposition from his peers. Both large tusks and large body size exert positive influence on achievement of a socially dominant position in male walruses (Miller 1975a)” (Fay 1982:135-136)

“Ancillary functions of the tusks include their use as weapons, both offensively and defensively.” (Fay 1982:136)

Journal article
Ecology and Biology of the Pacific Walrus, Odobenus rosmarus divergens IlligerNorth American Fauna, 74: 1 – 279January 1, 1982
Fay FH

Living System/s

Organism
WalrusOdobenus rosmarusSpecies