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Welcome to “Marine Mammal Highlights”, the next in our new series of blogs!

Over the next few weeks we’ll be sharing some of our favorite marine mammals and giving you some fun facts and biology about each one. For a more interactive experience you can listen to our “Marine Mammal Highlights” discussions on YouTube, or in audio-form on our brand new podcast, “PacMam Podcast” (available wherever you like to listen)!

Over the next 3 weeks we’ll be sharing our favorite cetaceans (whales, dolphins, or porpoises), and in the first of these Dr. Cindy Elliser explains why her favorite is the Narwhal:

The Unicorn of the Sea: The Narwhal

The unicorn is a staple in many myths, legends and fantasy.  Everyone knows about the magical horse with a beautiful spiral horn on its head, but did you know that myth is based on reality? 

In the cold waters of the arctic of Canada, Greenland, Norway and Russia, European whalers found a curious creature, a whale with a horn! Well, not a horn, but a tusk actually. They brought the tusks back to Europe, spinning tall tales of what kind of animals the tusks were attached to. And let’s be honest, a horse with a horn seems more plausible than a whale with one, especially one that can reach 10ft long!

Even though the narwhal is real, it is shrouded in almost as much mystery as the mystical unicorn. They live in remote places which are dark for half the year, and covered in ice for half the year too, which makes field work extremely difficult.  Thus we know relatively little about narwhals compared to other cetaceans (whales, dolphins, and porpoises). But what we do know is pretty cool!

Let’s start at the beginning. After spending 14 months in the womb, they are actually born grey or greyish brown.  As they age they become whiter.  The grey becomes black with overlapping white patches in a mottled pattern.  The name narwhal actually comes from the Norse ‘Nar’ ‘hval’ which means corpse whale, referring to this coloration which Norse sailors thought resembled the skin of a drowned sailor.  Though I think their coloration is much more beautiful than that dark analogy.

Now their horn, or more accurately their tusk, is a tooth that grows in a twisting, counterclockwise (or lefthanded) spiral!  Their scientific name, Monodon monoceros, means one tooth one horn in Greek.  This is the only tooth the narwhal has (except for the other tooth that is embedded in the skull; rarely this one will grow into a second, shorter tusk).  They don’t have any teeth in their mouth.  This one tooth continues to grow throughout their life (hence it can reach 10 ft!).  So why is it spiraled? Think about other tusks, like the elephant and rhinoceros, they are all curved.  The twisting allows it to grow straight, even if the deposition of material at the base is uneven.  It is even flexible, able to flex several degrees in any direction.

Pod of narwhals, northern Canada, August 2005. Image courtesy of Kristin Laidre.

All males have this tusk, while only 15% of females do.  The big question is WHY?  Well, it isn’t for dueling (though that would have been pretty cool!), or for spearing prey (how would they get the fish off the tusk?).  Only recently have we started to discover the why (and we still don’t know fully).  In 2014 it was discovered that it is a backwards tooth – with the nerves (up to 10 million!) and tiny holes on the outside, with the dense material on the inside of the hollow tusk.  This discovery in 2014 highlighted the main function: a sensory organ!  They can sense chemical changes in the water which could help find prey, or mates.  So why just the males? It may be that it is something like a Lion’s mane; the females may use the tusk to assess the fitness of the male (better tusk = better sensing = find better food/stay away from danger/find mates = stronger male).

Although there may be other uses.  They have recently shown that narwhals can stun prey with their tusk (https://www.youtube.com/watch?v=OoTjLIN67Bw).  They have been seen rubbing tusks – perhaps they are transferring information about the environment.  It may also be a part of their social structure, establishing dominance and ranks within pods.  These mythical looking tusks are likely multifunctional, and we are just scratching the surface about this unusual tooth.

Much research has focused on this most unique feature, but we do know some other basic information. Narwhals can weigh 1,760 – 3,530 lbs and measure 13 – 18 ft in length. Like many other toothed whale (odontocete) species they can live up to 50 years.  They feed (by sucking them up!) on things like halibut, cod, squid and shrimp – eating more in the cold winter than in the ice free summer.  This may be due to low productivity in the arctic in summering areas, or a way to avoid competition with the many baleen whale species that come up to feed in the summer.  They can dive up to about 5, 900 ft, able to sustain intense pressure for a long time, something few other animals can handle.

I have always had a special place in my heart for narwhals.  Perhaps it is because behind marine mammals, horses are my second favorite animal (and thus unicorns as well, I mean come on, magical horses?).  Couple that with their amazing features, and perhaps the mystery around them as well, it isn’t hard to see why the narwhal would be one of my favorite marine mammals.

Will still have so much to learn about narwhals, those enigmatic unicorns of the sea.  Their Inuit name, Qilalugaq qernartaq, means ‘the one that points to the sky’, describing their behavior of pointing their tusk straight up out of the water.  May they point us in the direction of knowledge about them, their ecosystem and how to protect them.

cindy.elliser@pacmam.org

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