Sunday Mammalfest, Episode 6

Walruses: large marine mammals living in arctic areas, recognisable by their distinctive tusks.

Narwhals: large marine mammals living in arctic areas, recognisable by their distinctive tusks.

Why tusks? What tusks? And for how long? Find out, as we enter: tuskworld…

walrus-group

Several notable differences stand out between the two species’ respective entuskments. The narwhal has one tusk, and only if it’s male (although entusked females and double-tusked individuals occur occasionally), while all walruses have two. Moreover, they are different sorts of teeth; the narwhal’s 3-metre-long tusk is an overgrown incisor, while the walrus’ 1-metre-long tusks are overgrown canines.

In both cases there’s uncertainty about the purposes to which the tusks are put, but they both seem to be mainly a status thing, used for display and fighting. The bigger your tusk, the more respect people give you.

They are also useful in relation to ice, for breaking holes in it or, in the case of the walrus, dragging oneself up onto it. This makes sense of why these tusks are found on mammals, but not fish (the beak of a swordfish works quite differently) and in arctic species but not temperate or tropical ones (or even antarctic ones). In the arctic there is a fucklot of floating ice (unlike the land-based antarctic), and this can pose a problem for mammals, who need access to the air to breathe.

It seems likely that this utilitarian function may have been the original reason for the development of tusks, which then became a sexual signal, like a peacock tail: only fit and healthy animals can grow large tusks, so animals with large tusks become more sexually successful and thus the tusks grow longer. This would also explain why narwhal females don’t have tusks, since sexual competition is generally less important for females – and unlike female walruses, they never have to drag themselves out of the water.

Note that it’s currently considered that probably neither species use the tusks in feeding or foraging. Both eat fish, although the walrus has a greater fondness for shellfish which it collects from the seabed.

In relation to this, it should be noted that walruses suck, hard. The walrus’ mouth is specially constructed so as to create powerful suction forces which allow it to suck clams and such like out of their shells. They are in this way sort of the polar opposite (no pun intended…well ok that’s a lie) of pangolins, whose mouths are complex machines for blasting their tongue outwards.

As a final note, the creature below? NOT A WALRUS. A fortiori, not a ‘lolrus’ either. Rather, a southern elephant seal, one of the few pinnipeds (seals, sealions etc.) larger than walruses.

An elephant seal is robbed

An elephant seal is robbed

5 Responses to “Sunday Mammalfest, Episode 6”

  1. DOMINO Says:

    *Chuckles bemusedly thinking about swordfish beaks.

  2. rumblegumption Says:

    From ‘Dogma’:

    Nun: You don’t believe in God because of Alice in Wonderland?
    Loki: No, “Through the Looking Glass”. That poem, “The Walrus and the Carpenter” that’s an indictment of organized religion. The walrus, with his girth and his good nature, he obviously represents either Buddha, or… or with his tusk, the Hindu elephant god, Lord Ganesha. That takes care of your Eastern religions. Now the carpenter, which is an obvious reference to Jesus Christ, who was raised a carpenter’s son, he represents the Western religions. Now in the poem, what do they do… what do they do? They… They dupe all these oysters into following them and then proceed to shuck and devour the helpless creatures en masse. I don’t know what that says to you, but to me it says that following these faiths based on mythological figures ensure the destruction of one’s inner-being. Organized religion destroys who we are by inhibiting our actions… by inhibiting our decisions, out of… out of fear of some… some intangible parent figure who… who shakes a finger at us from thousands of years ago and says… and says, “Do it – Do it and I’ll fuckin’ spank you. “

  3. Eusthenopteron Says:

    What about Odobenocetops? I don’t think it was an polar species, but it had tusks…

  4. links for 2009-06-14 « Rumblegumption Says:

    […] Sunday Mammalfest, Episode 6 « Directionless Bones […]

  5. Alderson Warm-Fork Says:

    You speak of the prehistoric ‘walrus whale’, which now that I investigate does appear to complicate the issue. As I understand it, the fact that this species convergently developed both the feeding method of walruses (bottom-feeding to find bivalves and suck them out of their shells) and also developed walrus-like tusks has strengthened the supposition that the tusks are involved in feeding somehow.


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