Hello and welcome to another Fun Fact From Flora ,
Hasn’t it been a little while!? Never fear. This one is a good “un. Today we have a little look at narwhal tusks.
For a long time scientists have just been hella baffled by what these ginormous javelins sticking out of the faces of these whales are for. This is partly because narwhals spend a lot of their lives hidden underneath the Arctic ice.
So what is that tusk? It’s actually an elongated upper left canine. And when I say elongated I"m not kidding. It’s usually about 8 feet long.
People thought that maybe it was an environmental sensor , that it was used for opening breathing holes in sea ice, as a weapon or that it was used for hunting , but the weird thing is thatnot all individuals have one.
Females typically don’t have them, so the tusks cannot perform some aspect of narwhal-life that is totally essential , because females actually typically live longer than males.
A lot of studies have drawn different conclusions. One drone recorded narwhals using it to strike and stun small Arctic cod, before eating them.
(you can see the footage here and it’s badass)
But again, this cannot be their primary function , otherwise individuals that didn’t have them would fare so much less well than their tusked-compatriots.
THIS ONE THAT WASHED UP ON A BEACH EVEN HAD TWO
The tusks have also been analysed and shown to be highly innervated sensory organs with millions of nerve endings in them. So they could be used to detect certain stimuli happening in the ocean around them. Some have also postulated (excellent word) that males may rub their tusks together to communicate certain traits of the water they have travelled through.
But none of these explanations quite cut the mustard.
The leading evidence now suggests that actually they are an example of runaway sexual selection. Like the feathers of a peacock, or the crazy antlers of a stag — evolution has just got a bit overexcited.
You can understand how this might happen. A narwhal with a longer tusk is likely to be in better condition , after all it’s grown this mighty fine-looking tusk and still survived with it sticking out of its face, and so is probably going to have better babies. You should have sex with that narwhal.
That just leads to a relentless cycle. Those females breed with long-tusked males, producing daughters that find long tusks really sexy and sons that have really long tusks. You can see how it can run away a bit.
We know this because the tusks
vary in size
way more than you would expect for a functional trait. Sexual traits are very sensitive to
nutrient
and
body
condition*
Hope you enjoyed a little foray into the lives of our unicornly cousins.
Love Flora xxx
And here’s a GIF of an animal falling over
