In this episode of Shark Week: The Podcast, we take a dive off the coast of Guadalupe Island with our host, Luke Tipple, marine biologist and shark expert, as he gets up close and personal with a 20 foot Great White. Then he deep dives into shark anatomy and talks about the major differences in teeth between shark species from the species that have hundreds of teeth, to species that have thousands. At the end of the episode, Luke talks about the biggest sharks in the world and a shark species small enough to fit in your hand.
In this episode of Shark Week: The Podcast, we take a dive off the coast of Guadalupe Island with our host, Luke Tipple, marine biologist and shark expert, as he gets up close and personal with a 20 foot Great White. Then he deep dives into shark anatomy and talks about the major differences in teeth between shark species from the species that have hundreds of teeth, to species that have thousands. At the end of the episode, Luke talks about the biggest sharks in the world and a shark species small enough to fit in your hand.
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For more about sharks, head to SharkWeek.com
[00:00:00] Luke: Good day and welcome to Shark Week: The Podcast. I'm Luke Tipple, marine biologist, and a frequent voice on my favorite things, oceans and sharks. I'm stoked to bring the magic of shark week, right to your ears.
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[00:00:15] Luke: Sharks have been a big part of my life for over 20 years now, studying them and diving with them all around the world. I guess that's given me some of the street cred to participate in many Shark Week documentaries throughout the years. And now, to be your host. So, whether you've never seen Shark Week before, or you've been a diehard fan over the 30-plus years it's been around, this podcast is for you.
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[00:00:43] Luke: My fascination with sharks really started at about five years old. I was spearfishing with my dad. Well, I mean, he was teaching me how to spear fish; I was doing very badly! But I remember seeing him dive down and touch something that was on the bottom of the sea floor. And it looked very strange to me, but then it moved and I realized that's a shark.
[00:01:02] Luke: It was a, a wobbegong shark, which have these beautiful colorations that make them disappear into the rocks. And he looked at me and said, you know, kind of with a grin check this out. And he dove down and immediately my five year old brain thought, oh my dad's about to get bitten by a shark. This's gonna be awesome.
[00:01:16] Luke: He grabbed its tail and kind of spooked it a little bit. Not that I'm endorsing any of that, but as a five year old, it was kind of cool. And I realized, I'm hooked. I'm in love with these animals immediately. And that really started with seeing an animal that I thought could cause such massive damage actually kind of be afraid by a bigger predator. And I thought there's a deeper story here.
[00:01:36] Luke: And, you know, teeth are a good place to start as any, because they're really the most distinctive feature of a shark. You know, when we see them in movies or anything else, it's always that big jaw filled with teeth. And, you know, humans have a long, long history with sharks and shark teeth.
[00:01:53] Luke: We've used them as tools! We've used them as fighting implements, as cooking implements. We've found daggers and clubs with shark teeth embedded in them, all throughout the Americas. And we've long known about sharks and their, sort of, deadly capacities, but there's so much more to the entire species of sharks than just, you know, the one or two big, dangerous bitey ones that we might think about.
[00:02:17] Luke: Because some sharks are absolutely gigantic, but they have the tiniest, tiniest little teeth, which is kind of mad to think about. So let's break it down! There's four distinct types of shark teeth, and they mainly vary because of the species and also the diet and their target animals that they're going after.
[00:02:35] Luke: These are the needle-like teeth, the dense flattened teeth, the completely nonfunctional teeth and the pointed lower teeth. And I'm gonna break those down for you. Now, we think of sharks as having lots and lots and lots of teeth and, and they do. Most sharks as a generality, you can say, have between five and 15 rows of teeth per jaw.
[00:02:54] Luke: There's species, like the bull shark; they have around 50 rows of teeth, total, and there's species like great whites, who have about 300 teeth, total. There's whale sharks, believe it or not, who have up to three thousand teeth total, but they're entirely useless in feeding or anything else really. They're just kind of very small and really just there's window dressing, ‘cause those animals are filter feeders.They're not really going out and predating on anything that requires chewing or biting.
[00:03:24] Luke: I find that the, the flattened teeth, even though we don't see them in, you know, movies or anything all that often, are actually some of the most fascinating because they involve a lot of evolution. They're mainly used for crushing food and they crush up shells and stuff, things like crustaceans and bivalves.
[00:03:42] Luke: These are animals like the wobbegong, that I described earlier. These are also animals like the angel sharks and nurse sharks. And, these sharks you'll find sitting on the bottom of the sea floor. They're often ambush predators. They might be waiting for something to walk past them like a crab, or, they'll be hunting in the rocks and finding something to crush up and crack and get that lovely meat from the inside.
[00:04:04] Luke: The more typical shark species we think about, they're ones like bull sharks and blue sharks, you know, these big, super predators; they have what we call needle-like teeth, very, very sharp teeth.
[00:04:15] Luke: And this is what we see hyped up in TV so often. Now, they have these teeth because they need to grab stuff that moves really fast. I mean, think about it! You're a fast moving animal, hunting fast moving animals. And have you ever tried to pick up a fish? It's not easy. Even dead fish are hard to pick up sometimes. Now, try to imagine grabbing one that's wriggling through the ocean at, you know, 30 miles an hour.
[00:04:36] Luke: You need something that just stops it like a vice. And that's these sharks with these needle-like teeth that can quickly grab an animal. They can grab a fish, they can incapacitate it and treat it as food.
[00:04:49] Luke: They spend most of their energy on quickly grabbing the food and then they consume it kind of afterwards. The sharks that have these teeth are impressive. They're, you know, blue sharks and hammerheads and, and some of these animals that, when you look into their mouth, it is just formidable. Now, when we're talking about formidable, we have to talk about the great white shark.
[00:05:09] Luke: They're the most famous jaws, probably on the planet. I mean, they had a movie named after 'em. But, they have these pointed lower teeth and triangular unique upper teeth and the upper teeth have these serrations on 'em that are extremely effective at cutting into prey. Now, I can tell you from personal experience, having one of these sharks come at you with intent… It's a formidable experience.
[00:05:34] Luke: I've worked for a long time with great whites, particularly down in Guadalupe. I was one of the pioneers of out of the cage swimming with great whites. And I can remember during a fairly controlled scenario but, in retrospect, a somewhat, you know, risky scenario, we're working with seven or eight great whites at the same time and it's impossible to keep your head, you know, on a swivel enough to see them all, at all times.
[00:06:00] Luke: I entered the water and fairly immediately did my perimeter check. You know, I see the 1, 2, 3 in front of me. I know there was a shark that went under the boat. I saw him behind me. Okay. We're good. And then I looked down and there's a shark coming directly at me doing, probably, about 17 to 20 knots.
[00:06:17] Luke: It's coming very, very fast. It's quite deep, but I can see it's jaws open, the white of its belly, it's tail slashing from side to side, it's coming directly at me. And I know that that's because I'm the new thing on the top of the water it's coming up to investigate, but we're also surrounded by seals and all types of things so who knows what would've happened if my training hadn't kicked in. And, that training only comes from hours and hours and really decades spent in the water with these animals.
[00:06:46] Luke: And I very quickly turned over, looked it straight in the eyes and swam directly at it, which was fortunately the thing that stopped what could have happened, happening.
[00:06:54] Luke: And, I hate to say that could have been an attack, it could have been a bite, because it could have just been investigating as well. I don't wanna put that on the shark, but at that place in time, I'm pretty sure that, I'm here walking around with two legs because my instincts were to swim towards that great, big mouthful of teeth.
[00:07:12] Luke: I can tell you those teeth are big. Now, some of those teeth, they can be absolutely gigantic, they can be inches big. Now, tiger sharks have very particular teeth. And I wanna talk about them because they're just absolutely formidable. Now, imagine this, take your finger and turn it into a hook, kinda like a Pirate's hook or something like that.
[00:07:30] Luke: Now imagine taking that finger and dragging it through a bowl of jello or dragging it through a bar of butter. Now that's kind of how a tiger shark feeds on a turtle. Now these teeth they can grab and not let go. And by shaking side to side and tearing through that shell, they can get into the meat of what that turtle is.
[00:07:52] Luke: And I've seen this in person. I've come across three tiger sharks attacking a turtle before. It's actually a very cruel thing to watch because they toy with it until it drowns. They grab it, take it down the bottom and wait until it moves around a little bit and then they'll let it go and let it swim to the surface.
[00:08:08] Luke: And the next one will grab it and take it down the bottom. And they'll keep doing that until the poor turtle wears out and it expires and drowns. And then they'll grab the shell with their teeth and just tear it to pieces and feed on what's inside. Brutally beautiful thing of nature to see.
[00:08:26] Luke: Let's move on to the completely nonfunctional teeth. I think of these as kind of the fun teeth of sharks. These are sharks like the whale shark and the basking shark. And, the thing that is so weird about these sharks is that they're the biggest ones. The whale sharks and basking sharks are so much bigger than any of the predatory sharks that we really think about.
[00:08:44] Luke: And they really just feed on plankton and small fish. Their teeth are so small that they're completely nonfunctional. They're just a row of just dentition in the front of their mouth, almost just like hard plates. But, they don't need 'em, they've evolved to a much easier way of feeding. They don't need to use all their energy in chasing around fish and they can just feed on plankton, just open their mouth, cruise along, get big and fat and have babies, which sounds like a pretty fun thing to do.
[00:09:12] Luke: Now, shark teeth are attached to their gums by soft tissue. So they don't have a root like us and they, they're not really that firmly stuck in their mouth and they often fall out. And that's why we find them on the sea floor or you'll see them used in tools and stuff, because it's actually quite easy to get them out.
[00:09:31] Luke: They can go through tens of thousands of these teeth in a lifetime. In fact, one example that comes to mind is a sandbar shark. And if you've seen these sharks, a gray nurse is another word for them, they have these formidable teeth that kind of stick out, just these rows and rows of teeth. They're actually a very benign shark.
[00:09:48] Luke: They don't have hardly any incidences of, you know, attack or bites on humans. And they're pretty benign really. Now, those sharks will go through about 35,000 teeth over the course of a lifetime, that's absolutely incredible. And, before you feel too much pity for these poor sharks losing their teeth all over the sea floor, they replace them very, very quickly.
[00:10:10] Luke: You know, you remember I said they'll have rows and rows of teeth. Those teeth, they're not baby teeth or anything. They're fully functional teeth and they'll snap into position as needed. So they really are just such a perfectly designed predator, where they can use their teeth for what they're needed to do, which is to be sharp, fast, and effective.
[00:10:29] Luke: And, when they get torn out or ripped out or blunt, then they can just replace them, which I think is absolutely incredible. Now, one more thing I've mentioned about teeth is the fun little party fact that you can take to people. They arguably have the most healthy teeth in all of the animal kingdom. The surface of their teeth is 100% fluoride.
[00:10:48] Luke: So, in theory, sharks won't suffer cavities. I mean, they never keep their teeth long enough to get a cavity, but in theory, they wouldn't get them. And that's something that I wish us humans had been smart enough to evolve throughout the time so that my dentist wouldn't want so much money.
[00:11:14] Luke: And with all that dentition, we're used to seeing them embedded in jaws. And, you know, you can walk into any old fishing place or something and see these great big jaws with great big teeth, you know, emblazoned on the wall as a hero trophy of the shark that I wish they hadn't have caught and had let go, but, regardless, pop culture has given us this image of teeth stuck in jaws.
[00:11:36] Luke: People have spoken to me and said, you know, how do you get the shark jaws? And why don't we see the rest of them? Well, the really interesting thing, and to some people, this would just be like, of course, but to some people, it's a revelation, that sharks don't have bones. That jaw you're seeing that holds all the teeth is not a jaw bone per se.
[00:11:54] Luke: It's actually just very, very tough cartilage. Now sharks are from what we call class chondrichthyes, which means, literally, cartilage fish. That’s as opposed to osteichthyes, which are bony fish. And you don't have to remember that, there's no test afterwards. But if you do wanna remember a word it's Elasmobranchii or Elasmobranchs, it's the subclass of sharks, rays, skates, and sawfish.
[00:12:20] Luke: These are the animals that we're very, very focused on and they all have cartilage rather than bone. You know sharks, as I said, they don't even have a single bone in their body. So how does cartilage do all of that? Now, I mean, what is cartilage? Grab your nose. That's cartilage! Grab your ear, twist it around. That’s also cartilage!
[00:12:38] Luke: Now, you'll notice, that they're different. Right? Well, imagine an animal that has evolved for millions and millions and millions of years, exclusively using cartilage. You'd think that some of that cartilage would be specialist… and it is! The cartilage is extremely tough and it does exactly the same job as a regular skeleton, you know, made of bones like ours would do, in that it gives their bodies shape and structure, and it protects their organs.
[00:13:04] Luke: But the areas that need much more protection, most species of sharks will be able to calcify those bits of cartilage. So, for example, the shark's head is largely made of calcified cartilage so that their brain is protected. And, so that their jaw is nice and strong to hold all of those super gnarly teeth.
[00:13:23] Luke: And, other parts of their body will have some of that cartilage that's just a little more or less flexible. Of note, are the shark fins. So, we all have heard about shark fin soup. The goal of shark fin soup is simply to eat the cartilage. Well, actually, I'll back up on that. I think the goal of shark fin soup is that people can feel self important as they're trying to suck down a shark because the cartilage doesn't have flavor.
[00:13:49] Luke: It's completely useless, there's no nutritional benefit whatsoever. And people are just eating it as a cultural or as a a status symbol. And it's really a practice that needs to stop. But, if you've ever seen a bowl of that, it'll just look like noodles and really that's the cartilage that's in there. Now, one of the first things I thought about when I started swimming with these larger sharks in particular, is their grace in the water.
[00:14:13] Luke: You see how smoothly and calmly they swim through the water and then, how quickly they can turn on that predatory instinct. It's absolutely incredible and a big part of that is in their not having bones. That cartilage is super flexible and it's also very light. If you couple that with a super large liver, that's full of oil, that can help with their buoyancy, you've got an agile, fast, incredibly flexible animal that can eat a lot of things very efficiently.
[00:14:41] Luke: It's a pretty cool thing. Now, even though sharks don't have bones, they can still somewhat fossilize. So, we have found fossilized remains of sharks. It's mostly the teeth, little bits of jaw, but we don't get what people traditionally think about, you know, as fossils, you know, we don't get this big dinosaur bone discovery of sharks.
[00:15:03] Luke: So, most of what we know about sort of the prehistoric sharks, we have to interpret, basically from their teeth. There's also something very interesting about their body that we should know. It’s that their body is entirely covered in teeth, it's not just the ones up in their mouth. Their skin is made of a thing called dermal denticles.
[00:15:22] Luke: Now dermal denticles is literally, as it says, it's skin teeth. And if you look with a very high powered microscope at a shark’s skin, you can see just rows and rows and rows and rows and rows of teeth that face backwards. And they give them this extremely efficient hydrodynamic surface that makes them slip through the water.
[00:15:42] Luke: In fact, this is the surface that swimmers have interpreted and use now for their swimming outfit so that they can go really, really super fast. I don't know if those things are banned yet. They probably should be, but it's a really efficient system. And, when you think about the advantages of having all those teeth, a cartilaginous skeleton, skin that's literally built to make you go fast, you can see why these animals are such efficient predators.
[00:16:09] Luke: Now, when we talk about sharks, we also have to talk about the environments in which they thrive. And, it's such an incredible group of animals because they really have inhabited every single body of water on the planet, that's ocean connected.
[00:16:22] Luke: Which is just an incredible thing to think about. They are specialists. So, we've got everything from the very, very largest sharks. You know, the whale sharks, that are filter feeding on plankton, right down to the very, very smallest sharks, which you wouldn't probably even think about as a shark, but they certainly are. You know, the smallest one is called the dwarf lantern shark.
[00:16:44] Luke: It grows about six to eight inches long, which is about the size of your hand. You know, this isn't a shark that's gonna be on any movie anytime soon, trying to scare the heck outta you. This is a shark that is extremely specialized in very, very small things. Now, if we go the entire other way, we look at the greatest, actually, one of my favorite sharks on the planet.
[00:17:06] Luke: It was the first shark that I worked with outta college. I was super fortunate in that I graduated. I didn't even pick up my diploma. I'd already applied for a job in Honduras to be the resident marine biologist. I was gonna tag Great Whites… uh, no, I was gonna tag whale sharks and, I was off. A pro tip for all you kids out there who are graduating from college. Go to your graduation ceremony because, I can't tell you the amount of these nightmares that I have, or I wake up in a cold sweat and I think, oh, did I graduate?
[00:17:36] Luke: I have these dreams about not graduating and just not having a diploma. And after all this work, I'm like, oh, did I finish or not? And that's because I guess I didn't go to my graduation ceremony. So, that's a nice piece of trauma to talk about on a podcast.
[00:17:49] Luke: But, I did get to go work with whale sharks, which was an absolute privilege and one of my favorite things to do in the world, because I got to see the biggest shark in the world in purely depthless blue water and shoot it with a spear gun. Which to me was one of the greatest thrills of my scientific life.
[00:18:07] Luke: It's probably not what most people would think about doing if they saw a shark that big, but they can get to over 60 feet long. That's 18 or 19 meters long. It's rare that they get to that long. They're usually between about 18 and 32 feet, maybe five to 10 meters. And the ones that I was working with were in the upper range of that, 30 to 40 feet, but the big ones are absolutely gigantic.
[00:18:32] Luke: They can weigh about 30 tons and they'll give birth to up to 300 pups. Now, not many of them will make it to adulthood, of course. They have a specific birthing strategy in that they'll put out a whole lot of them and hope that a couple of them last. But, the whale shark is just such an absolutely incredible example of a very, very large animal eating the smallest possible thing.
[00:18:57] Luke: It's kinda like elephants. When you think about it, you know, elephants are out there grazing on grass and stuff, and they've grown to be one of the biggest animals on the earth. And it's just like that in the water. Other massive sharks that are worth talking about; the basking shark, the megamouth shark. They're, you know, basking sharks get about 50 feet, megamouth’s around 25 and that's when we get past those sort of filter feeding sharks.
[00:19:22] Luke: And we get into the predatory ones. They're much smaller comparatively. The predatory ones that we like to think about; the great whites, tigers, even Greenland sharks and hammerhead sharks, they typically are around that 20 feet long range.
[00:19:36] Luke: Since we're talking about sharks, we may as well talk about one of the biggest baddest sharks ever to exist on this planet, which was the Megalodon. And, before anybody pipes up and starts talking about “that it could exist”... it's dead. It's gone. It's fossilized remains have been found and that's it. So, no amount of TV or movies or anything else will ever convince anybody with the knowledge of sharks that Megalodon is still around. It is not.
[00:20:03] Luke: So you can swim with a little more comfort. Great whites are still around, but Megalodons are not. Now, megalodon is notable because it was the largest fish that's ever been known, and it was the largest shark that's ever been known.
[00:20:16] Luke: And to put it in context, when we talk about that as compared to say a whale shark, they are about the same length, about 60 feet long. But the Megalodon was three times as heavy. They got super, super massive and super fat. So, you know, comparing that to a whale shark, the Megalodons got to about 60 tons, which is just ridiculous.
[00:20:40] Luke: So, while I think it's unfortunate that they don't exist because I'd love to be in the water and swim with one, just to say that I did and just to have my mind absolutely blown. It's probably for the best of the planet right now that they don't exist. All right, that wraps up another episode of Shark Week: The Podcast
[00:20:56] Luke: Stay tuned to this feed for shark facts you don't wanna miss and interviews with shark experts that will give us a behind the scenes scoop on what really happened out at sea. And… a lot happens in a month out at sea, and yes, we're keeping the shark passion alive after shark week is over, covering the Sharkiest current topics, talking to top scientists and experts to learn all about the latest conservation efforts in keeping this amazing animal from extinction.
[00:21:22] Luke: Thanks for listening to Shark Week: The Podcast. Be sure to rate us five stars and subscribe for more shark fun facts. I'm Luke Tipple. I'll see you next time.