I suppose I should answer the first question people have about this blog: What’s the title mean?
As most people know, one of the most amazing things about the narwhal -- and its most notable physiological feature -- is that it has a tusk. A spiral tusk that can extend up to eight feet long. And that tusk is a tooth, one of only two teeth in its jaw.
The left tooth erupts through its upper lip and becomes its tusk while the right tooth remains impacted in its jaw and only rarely does it grow. One narwhal researcher called the tusk “the most unusual tooth in nature” and perhaps the only example of asymmetry in teeth in the mammalian world. (I should note that except in rare cases, only males have a tusk, and a very tiny percentage of males have two tusks.)
Perhaps equally bizarre is that fetal narwhals show evidence of four teeth – two in front and two in back – but by the time they are born, the two original back teeth have disappeared and the two front teeth have migrated to the back. Why it would do that is anybody’s guess. The narwhal’s tusk is also remarkably flexible for a tooth, and incredibly heavy.
That’s a lot of cash for a narwhal’s left tooth.
Of what actual use is the tusk? Spearing food? Fighting?--
ReplyDeleteWHY did it evolve like that and then be the only creature which has such a thing— or were there others in early history.
Do tusks ever break in the course of a narwal's lifetime?
There has been lots of discussion over the years about why narwhals have a tusk. Most biologists believe it is a 'secondary sexual characteristic' like the deer's antlers or the peacock's feathers, to demonstrate dominance over other males and to attract the females. I'll discuss the ongoing disagreements on this topic in a future posting. Tusks do break on occasion, so that is not an unusual occurrence, though no one knows exactly how or why it happens.
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