The Insane Biology of: The Narwhal

for centuries humans have been entranced by the mystical powers and ethereal beauty of a mysterious spiraling horn a horn that was thought to possess magical qualities from purifying water to counteracting poisons and deadly diseases if ingested its powers were so sought after that Queen Elizabeth paid 10,000 for a horn in the 1500s 6.3 million in today's money but Queen Elizabeth and all the other previl of this magic horn got certifiably Bamboozled the horn they so coveted was a real thing and it probably inspired the Unicorn Legends but the actual creature is not quite so ethereal maybe you're thinking that's still a majestic creature even if it's not a unicorn yeah maybe you would think that until you learn that that spiraling horn is actually a tooth an extremely long weird buck tooth the Narwhal somehow gets away with this but any other animal with a single 3 m long tooth would be immediately cancelled and things don't get better when you learn the name narwhal comes from Old Norse meaning corpse whale because the color of their skin resembles a drowned sailor gross and honestly they just keep getting weirder the more you learn scientists attached satellite trackers in cameras to narwhals and observed them spending the majority of their hunting time swimming upside down in rare cases belugas and narwhals have even mated to create the hybrid narluga narwhals are also one of the few sattian species that polar bears will actively hunt rather than waiting for a dead carcass to wash ashore which means they have to be especially careful about where and when they come up to breathe but even despite this they have an incredible lifespan with estimates that they can live up to 100 years because narwhals are not just weird but also incredibly hardcore narwhals are one of the deepest divers swimming as far as 1,800 M underwater to hunt for food and going especially deep in the winter they manage 18 to 25 Dives per day thanks to their thick blubber that provides insulation and energy collapsible ribs that bend under high pressures and an incredible ability to store 70 lers of oxygen in their lungs blood and muscles their bodies don't have the fast twitch skeletal muscles that give Dolphins such propulsive speeds and instead have muscles better able to handle endurance swimming requiring less oxygen but the biggest question about them is what's the deal with that horn or rather that big old tooth it's certainly fun to try to guess multi-tool Intergalactic antenna supersonic speed kebabs Predator evasion a meter of its lies but Jokes Aside scientists still don't really know the real answer some past theories about its purpose included sound transmission thermal regulation breaking ice and even a breathing organ but since it's usually only males who grow the horn it can't be critical for survival and yet some females do also have the horn too so it also likely isn't just to be for mating so what the heck is going on here what on Earth are these long protruding teeth horns for narwhals belong to the odonto cetti or toothed whale order like their distant relatives the sperm whale and the Orca narwhals are endowed with teeth but only two of them and in their case the teeth are actually known as tusks female narwhals have two tusks embedded in their jaw which rarely become visible in about 1.5% of females one of the those tusks will grow into a huge spear just like the males and in some cases males will have no Tusk though sometimes they'll also grow too for reasons we don't really understand even though the horns are called tusks they have a very similar Anatomy to other mamalian teeth the outer layers of the Tusk are hard material to protect the nerve at the interior the outermost layer is cementum a calcified material to protect the tooth immediately beneath it is the Dentin which is more bone-like and immediately surrounds the pulp tissue what's unusual about narwhals is that they have no enamel covering to protect their Tusk and the cementum and Dentin actually have fluid filled channels called dentinal tubules that interact with the environment and pass messages onto the nerve which goes directly to the brain all Maman teeth have these channels but they're generally covered by enamel otherwise the tooth becomes hyp sensitive to s Uli and painful think about what happens when you bite directly into a popsicle I can't even watch people bite into an ice cream without cringing many people are like me and experience discomfort in their teeth because our teeth are sensitive to the sudden temperature change and that's with a coating of enamel protecting our dentinal tubules yet narwhals have a 2 to 3 m projecting tooth without any enamel which is nearly always immersed in Arctic ice cold water we don't know for sure that they get toothaches but it certainly seems uncomfortable to have a fully innervated and sensitive tooth constantly exposed to icy water but maybe there's a good reason for such a sensitive tooth so researchers devised a fascinating test to see what it might be useful for they decided to measure how well a Tusk can detect changes in water salinity this is potentially a very important adaptation because one of the risks of living living in the Arctic is getting stuck in what's called an entrapment narwhals breathe air like all mammals but they live in an environment that's absolutely covered in ice of the 25,000 Square km waterways they Traverse there's often less than 3% open water and sometimes as little as half a per of open water and they absolutely can't break through the ice with their tusks and if the weather changes suddenly with a burst of cold and wind ice can form incredibly rapidly closing off the areas that narwhals need to surface to breathe the whales can become stranded without enough breathing holes and hundreds will squeeze into shrinking openings in the solid ice many unfortunately die if they can't get to the small ice Gap in time and the ones that do manage to battle for space to breathe become easy prey for polar bears that gather around the breathing holes between 2008 and 2010 alone Loc reported for entrapments of large groups of narwhals up to 600 individuals due to the sudden growth of sea ice so how does salinity factor into the dangers of entrapment because the ice contains very little salt only the water freezes so the water around newly formed ice becomes much saltier than it is in other locations that means being able to sense a sudden increase in salinity would be very helpful for narwhals because they'd know it it was time to book it and avoid getting trapped in the ice now back to the study researchers captured six male narwhals and hooked them up to electrodes to detect their heart rate then made a jacket for the Tusk so that they could fill it with fresh water and then a high salt solution the researchers found that narwhal's heart rate fell with freshwat and Rose dramatically with salt water probably because the Narwhals were panicking about being trapped in ice though that's not something we can ask them directly what the test did confirm for researchers is that the tusks have sensory capabilities and that if the Tusk is damaged as was the case for two of the males they have a harder time detecting salinity changes and we know narwhals travel in pods sometimes with hundreds of members so maybe those who don't have a Tusk are just taking signals from the ones that do but that doesn't explain what happens with an all female pod when none of them have tusks so it seems like the Tusk can't just be for this there's got to be more going on with this protruding tooth horn despite the fact that narwhals only have two teeth and neither are adapted for chewing they actually eat fairly sizable fish including hbit Cod and gonatus Squid they find their prey using echolocation then swallow them whole using a strategy called suction feeding basically they create a vacuum in their mouth by retracting the tongue and just slurp up the fish although narwhals are very hard to follow in the wild we've learned a good amount about their diet thanks to their long history of being hunted scientists have studied preserved remnants of their stomach as well as stable isotopes of carbon and nitrogen in their skin to understand what they're eating and how deep they're going to get it in the past researchers thought narwhals were picky eaters and would therefore be more likely to suffer from the combined effects of climate change and over fishing but a recent study compared the world's three main narwhal populations from the Baffin Bay the northern Hudson Bay and East Greenland the scientists were surprised to discover that their diets were quite varied from one place to another in East Greenland the Narwhal seem to feed more in a pelagic food web especially on kaalan fish the North Hudson Bay narwhals did the most Ben thic feeding partly explained by the fact that they live in shallower water they largely ate benic shrimp the Baff and Bay narwhals had the highest levels of nitrogen 15 Isotopes which means they feed at the highest trophic level of the three groups including a lot of hbit but possibly the most interesting of all was the differences between male and female diets males are significantly larger than females and it seems that they make more frequent and deeper Dives so they can feed on benthic species more easily it's possible that their greater size allows them to hold more oxygen for these Dives and then there's the presence of the Tusk using it to stab prey Kebab style seems like a bad idea because the Narwhals then wouldn't have any way of getting it off their Tusk but in 2017 scientists captured footage of narwhals using their Tusk to smack fish which seemed to momentarily stun them IM mobile and from there the Narwhals could more easily Hoover up the fish this Behavior has only been seen once so it's impossible to say if it's a widespread practice we also don't know if it makes males better Hunters than females but that certainly doesn't seem to be the case so it seems like there still must be something more to this tooth horn we've seen that narwhal tusks are sensitive to the environment around them and useful for bopping fish on the head but are these the real purposes of naral tusks or just a nice side benefit when a specific trait appears in the males and not the females of a species scientists look at a couple of Clues to try to figure out whether that trait is the result of sexual selection or not one of the first things to examine is Fitness not in the jimro way but in the context of being able to survive the environment in other words are female narwhals without a Tusk capable of thriving in the Arctic the answer is yes which suggests the Tusk is not a crucial element of survival so is this horn perhaps something more to do with mating or sexual selection to understand this it's important to consider hyper allometry which is common in sexually selected traits it means that for the organism's body size the sexually selected traits are larger than would be expected take the claw of a fiddler crab for example an important tool for aggressive posturing and for attracting mates as a male crab's body gets larger the claw doesn't grow in size with it in a one one ratio it grows even more this steep line has a slope of 1.56 meaning the relationship between these beefy Claws and body size is hyper allometric and Hyper allometry is common in sexually selected traits because more exaggerated traits can more easily signal your genetic quality to your mates even from a distance so do narwhal horns fall into this category to test the hypothesis that narwhal tusks are sexually selected researchers compared the body and Tusk size of 245 adult male narwhals collected from 1983 to 2018 sure enough they found the relationship between Tusk length and body length to be hyper allometric and another study found that a larger Tusk size correlated to a larger pair of testes and the Tusk keeps growing for the entirety of the narwal's life so that thing is getting longer and longer the older they get the real question about the Narwhal is whether the visual of a big Tusk alone is enough to attract a female or if the males have some kind of dominance display as well researchers have found that 40 to 60% of narwhal males have damaged or broken tusks and many of them have scarring on their heads and even bits of Tusk embedded in their jaw the tusks can't withstand direct ramming forces but they are resilient enough for lateral strikes this might explain why we sometimes see narwhal males crossing their tusks above the water maybe they're doing some kind of jousting performance for the females we just don't know because their breeding period tends to be in March and April when they're still living in the dense ice of winter you might also be wondering if these tusks are solely for the purpose of finding a mate how come narwhals also have the ability to stun fish and sense how salty the ocean is there is a couple of theories about that too maybe those traits have been obtained from The evolutionary ancestor of narwhals maybe the tusks were used solely for sensory purposes until some of the females started selecting males for the size of the Tusk on the other hand the Tusk might be currently evolving into a sense organ maybe its extra abilities are nice little add-ons we do know that crustacean claws aren't just about getting a mate but can also be used as weapons for hunting prey and for chemical communication who knows maybe someday all Nar walls will end up with horns male and female alike for now scientists aren't sure why some females end up with tusks or why some males have two of them the answer may be revealed in time depending on which whales seem to be gaining or losing tusks over the generations for now narwhals remain one of the ocean's most mysterious animals and even though I'm not a fan of a singular protruding tooth horn on most animals it does suit the Narwhal quite nicely there's something truly beautiful about pondering the complexity of evolution throughout the billions of years life has existed on this planet whether it's wondering about the existence of a strange whale tooth or pondering how a single cell becomes many reproducing mutating giving rise to the sponges worms jellyfish the invertebrates and the vertebrates the spilop pods birds reptiles mammals and eventually us there have been so many pivotal moments during the course of evolution that resulted in the world we know today and these moments are so fun to explore with the free-to-play game called cell to Singularity cell to Singularity is a non-fiction game available on Steam IOS and Android that takes you through Evolution where you start as a single celled organism and progress through the Tree of Life each biological upgrade brings you closer to engulfing an entire planet with a civilization on the brink of technolog iCal Singularity I have to admit I've become kind of obsessed with this game I'm not normally one for phone games I'm normally more of a doom scroller but this snaps me out of Doom scrolling I much prefer to think about reptiles and whales and the entire concept of evolution than airplanes falling apart or Russian politics it's easy to play and honestly really soothing with nice music and satisfying progression every time you open up sell to Singularity you get to see how many entropy points you've earned and to use them to unlock the next steps of evolution and every piece that you unlock gives you a short description of that evolutionary moment and reminds you of just how incredible every piece of The evolutionary puzzle is the game also has limited time events that run weekly in one of these events you get to explore the deep sea where it features the Dumbo octopus the vampire squid and the Beloved giant squid players can play the deep sea event again from April 10th to 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Channel: Real Science

Views: 554,058

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Id: gwAGYg81geQ

Length: 18min 21sec (1101 seconds)

Published: Sat Apr 06 2024