A (not-so) Inconvenient Tooth
July 28, 2017 9:10 AM   Subscribe

Many people know that the narhwal tusk is a single modified tooth (they’re certainly not unicorn horns). Meet the narwhal expert and dentist who has spent his life discovering that the narwhal tooth is even weirder than you’d think. But there's lots more to learn!

In addition to functioning as a sensory organ, the WWF has recently captured footage of narwhals using their tusks to stun prey before eating them.
More narwhal facts and adaptations.

In other weird-tooth species, male strap-toothed whales have 2 teeth that grow around their jaw, preventing them from opening their mouths more than 10-13cm, but it doesn’t seem to bother them much.

Babirusas (deer-pigs) have very impressive tusks, but there is too much of a good thing.

Musk deer are sometimes called ‘vampire’ deer due to their adorable fang-tusks.

Moving on to other head-protrusions, antlers are really cool, not least because antler cells can apparently be grafted onto other animals who will start to grow boney structures at the graft site. (includes non-graphic B&W pictures of lab mice with growths on their heads).

Shed antlers can be carved into intricate antler carvings. But be careful where you find them; in Canadian national parks it's illegal to pick up shed antlers, which have nutritional value for other species.

Finally, it’s good to remember that antlers aren’t horns (SL Youtube: the Brainscoop with Emily Graslie), though pronghorns are a bit of both. And, of course, remember that tusks are teeth (description of elephant tusk composition and growth).
posted by robot-hugs (18 comments total) 53 users marked this as a favorite
this is my first post and it's kind of weird but i just got real excited about tusks this week and had to share.
posted by robot-hugs at 9:47 AM on July 28 [22 favorites]

The main article is an excellent read, thanks! "The Octonauts" has a narwhal episode where their tusks' sensory abilities are featured, and now I'm eager to re-watch that with my kid and tell her more about this giant tooth.

On preview -- great first post!
posted by of strange foe at 9:50 AM on July 28 [3 favorites]

Thanks for putting this together, robot-hugs! That's certainly a lot to chew on. :)
posted by mordax at 9:59 AM on July 28 [1 favorite]

"But the second most wacky whale is the strapped tooth whale, formally called Mesoplodon layardii. It has two lower teeth that erupt and completely encircle the upper jaw and prevents the whale from opening its mouth. There are other wacky examples of teeth--the wackiest for a land animal is the warthog, their tusks completely encircle them and sometimes penetrate their own brain.

Somewhere along the line some animals missed the boat on evolution."

This makes me feel better about my own dumb teeth. Thanks, whale dentist!
posted by Atom Eyes at 10:04 AM on July 28 [1 favorite]

i just got real excited about tusks

You and Fleetwood Mac.
posted by Greg_Ace at 10:12 AM on July 28 [1 favorite]

fun fact about Narwhales : their blood is so iron rich that the meat is black!
posted by LegallyBread at 11:00 AM on July 28 [7 favorites]

Awesome FFPP!

My 9-year old thinks narwhals and unicorns are awesome and I will show her some of these later. You'll make her day. :7)
posted by wenestvedt at 11:06 AM on July 28 [1 favorite]

A friend of mine thought narwhals were a fantasy creature until she was an adult.

The most ridiculous part, though, is what made her reconsider this belief was Elf.
posted by RobotHero at 12:26 PM on July 28 [1 favorite]

the single long tusk is present in males and about 15% of females [4th link]

This puts some restrictions on any explanation of the tusk as primarily a sensory organ which detects salinity gradients such as the dentist in the 1st link seems to favor; if knowing salinity gradients at nine feet instead of a foot or two is that useful -- which is hard to understand on its own -- why isn't it useful for females too?

Narwhals have to find breathing holes in the ice in the dark of polar winters, since they don't migrate, and I'd guess breathing holes could have a different salinity profile from underneath the ice than holes which don't actually break the surface, and given that breathing holes expose narwhals to predation, as well as making a search more efficient, it might be nice to be able to find one from significantly below the surface instead of coming all the way up. That would make males specialists in pioneering new breathing holes, which would be essential in extending hunting territory. Which might be a natural role for males in the first place, since pregnant females probably wouldn't be able to hold their breath as long, and ought not to push themselves as close to their limits anyway.
posted by jamjam at 12:40 PM on July 28 [1 favorite]

I love this for a couple of reasons:

1. I know at least one person - a very intelligent, professional, curious person - who up until very recently did not believe narwhals are real animals.
2. This is so weird it proves they are real, because who would make this up?
posted by louche mustachio at 1:08 PM on July 28

I had forwarded this twitter post to my friend just this morning, because there are so many people in there saying they used to think narwhals were made up.
posted by RobotHero at 1:45 PM on July 28

MetaFilter: They're confounding to a dentist.
posted by GenjiandProust at 3:49 PM on July 28 [2 favorites]

did not believe narwhals are real animals

posted by flabdablet at 8:50 AM on July 29

Funny timing, the Smithsonian National Museum of Natural History has an exhibit on narwhals opening August 3rd.
posted by gudrun at 11:49 AM on July 29

Only yesterday I was telling my daughter that only male narwhals have tusks. I would hang my head in shame, but instead I'm just going to go through these links with her. Live and learn!
posted by widdershins at 7:07 AM on August 2

Wow. My brain expanded as a result of this post. Many thanks!
posted by yoga at 7:32 AM on August 2

Live and learn!

A little animal song.
posted by flabdablet at 2:15 AM on August 3

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