Animal Facts They Don't Teach You in School

Hello, these are all real scientific specimens used for research. Enjoy! So this is the rattle from a rattlesnake. I always wondered, how do rattlesnake rattles make sound? Well, if you look inside, you'll see that it's very hollow, and this was very surprising, because I thought rattlesnake rattles kind of worked like maracas. They had little bits inside of them that knocked around and made sound, but they're hollow, so that can't be the case. But look here, if I pull on the rattle, a piece comes off. It seems like the rattle can fit together in different sections. Here's an image that can help us see how all the sections fit together. One of the segments is highlighted in white. Can you see how all the segments kind of loosely fit inside of each other? Now check this out. Notice how the segments aren't firmly connected. There's kind of room for them to wiggle around and move. So when the rattle is shaken, those segments can knock together and create sound. It's not really the way I expected it to work, kind of like this guy. This is my favorite stingray, and I thought I knew how stingrays sting, but again, I got that one wrong too. Because if you look at the bottom, you'll see a long tail. I thought this was the stinger, but it's not the stinger. Look here, if I move that tail to the side, do you see that small barb? That's the stinger. Here's what it looks like removed from the stingray. Now look closely at that edge. It's dark and serrated and can easily cut into flesh. And here's the important part. Do you see those two grooves on either side of the middle of the stinger? Those grooves hold special cells that secrete venom into the flesh of the stingray's victims. Even this mini stingray has them. But he makes me wonder, why are stingrays always this color? Their underside is white, but if you flip them over, they're darker on top. I'll go into my collection of every fish ever and get some bigger rays to help us explain. Okay, so imagine we're in the ocean and we're looking at that stingray from above. The darker color helps it blend in with the dark color of the ocean. Now imagine we're looking at the stingray from below. Its lighter underside helps it blend in with the lighter colors of the sky. So the dark back and bright belly just help it camouflage while underwater, and it's not the only one. Sharks have the same color pattern. They're light on the bottom and dark on top. You also got penguins and normie fish and turtles, which have always made me wonder, how do turtle shells form? I kind of thought they were formed by the turtle's hard outer skin. Kind of like a fingernail, you know, but again, it's not. That's not how it works. This is a dyed turtle specimen. It can help us answer our question because dyed specimens are very unique. Here's another example. This is a seahorse. Check this out. The seahorse's flesh has been removed. Then it was soaked in a colorful dye, which stained its bones and cartilage. So this creates a dyed specimen, which doesn't only look pretty cool, but scientists use dyed specimens to reveal hidden structures inside delicate objects. Like in this seahorse, check this out. Instead of having regular ribs, kind of like us, it's made up of a bunch of rectangular plates that fit together to form its skeleton, which is very neat. But what can we find in that dyed turtle specimen? Okay, how are turtle shells formed? That's what we're wondering. Now, do you see those red lines on the turtle's back? Those are ribs. Here's a soft shell turtle shell. Notice how the ribs have flattened out and fused together. This Blanding's turtle shell is more of an extreme example. Check out how the ribs come out of the spine. They've completely expanded and then fused together along these lines. So a turtle shell isn't skin at all. It's a turtle's ribs that have expanded and fused together, which makes me wonder, is the same thing going on with pufferfish? What are pufferfish spines? Are they made out of ribs too, kind of like turtle shells? Well, let's go through my collection and snag this box. Let's open it up to find a pufferfish skeleton. Now watch closely. If I pick this part up and rotate it back, can you see how all the spines are layered on top of each other and kind of attached to the skin? Here's a look from another angle. Turns out pufferfish spines aren't ribs at all. They're simply super modified scales on the fish's skin. So spines are scales, they're not bones. But this is, this is a vertebrae from a giant blue whale. It's pretty cool because it's basically an enormous version of a human vertebrae. I never really understood why they were shaped like this, so let's check it out. So do you see this hole right here? That's the spinal cord goes through, kind of like this. And when I turn it on its side, do you see these two bony flaps that I'm holding? So the flaps on the next vertebrae slip in right here. Here's what it looks like. It slips in just like that. Now check this out. When they're together, there's a tiny little gap right where they meet, a hole right in the middle. Smaller nerves branch through this gap from the spinal cord towards the rest of the body. It's the same thing as human vertebrae, except yeah, it's a lot bigger. From one giant thing to another, this is a giant chameleon. Do you know how giant chameleons can launch their tongues really far? I thought they kind of did it by just spitting out their tongue really hard, but that's not the case. Here's another dyed specimen. It's kind of like that turtle we saw earlier, but this one's a chameleon. So let's flip it over. Do you see this bone in the middle of its jaw? This is the key to tongue spitting. Here it is along with the chameleon skull. It's right there. So a chameleon's tongue fits around this bone kind of like a sleeve and rings of muscle wrap around it, like a hand wrapped around a bar of soap. Okay, so when a chameleon wants to shoot its tongue, it squeezes those muscles, which shoots the bone forward, which launches the tongue that's wrapped around it. So chameleons spit out their tongue by squeezing a bone in their mouth, like a hand squeezing a bar of soap. But not one of these. This isn't a bar of soap. It's actually a miniature angler fish. They're like those fish that have small lures on the front of their heads. It's right here. It's that thing on their forehead that they kind of like dangle around and use to hunt. So I always wondered where the heck did this come from? So I went back into my collection of every fish ever and found a normal fish to compare it to. Okay, do you see any part of this fish that could potentially evolve into a lure? How about this long dorsal fin right here? Can you see how it's made out of a bunch of spines? Okay, so imagine if the front spine broke off from the That detached spine would form something kind of like a lure. So an angler fish lure is a spine that detached from its dorsal fin and just kind of scooted down onto its forehead. Okay, here's something that might be more familiar. This is a bushmaster. It's a kind of snake. And I've always kind of wondered, how do snakes use their fangs to inject venom? So let's find out. Okay, at the base of this fang, do you see that small hole? Here it is from the front. And now a little closer. This is the opening of a tube that runs right through the fang. When a snake bites, venom from the venom gland enters this hole and runs through the center of the tooth to the tip. Now, do you see that other tiny hole right there at the end? This is where the venom exits the tooth and enters the body of its prey, which is like some type of rodent or a bird or perhaps a giant rainbow cricket. Do you know how insects breathe? I didn't. And I think the answer is going to surprise you because they don't breathe out of their mouths like we do. Instead, take a look at this cricket's side. Do you see that tiny hole right there? That's called a spiracle. And if I zoom out, you can see a bunch more. Well, oxygen enters these holes. Then it's delivered everywhere else to the rest of the cricket's body. So insects breathe through a bunch of holes on their sides. But what about snails? Let's find this snail's breathing hole in the form of a poem. Perhaps they breathe right out their butts, just like some turtles do. But no, let's move more towards the front and set our field of view. Then zoom on in and get real close. You see it just right there? That tiny hole I'm pointing out is where snails suck in air. Yes, some land snails breathe out of pores that are kind of on their necks, tucked under their shells. I love when animals have sensory organs on weird parts of their body. And I think this is probably my favorite, a giant katydid. It's an enormous version of a common insect that's found in the United States. So katydids make a very familiar sound that I bet you've heard at night before. Listen to this. It's right here. This is not the sound of crickets. This is the sound of katydids. But I think it's much more interesting how katydids hear sounds. Katydids don't have ears on their heads like us. Instead, they're located in a very unusual position. We're going to try and find it. So while facing this katydid head on, let's locate one of its legs. This one will do. Now take a close look right below its knee. Do you see there's a small circle under there? Here it is close up. This is a very tiny eardrum. This eardrum functions just like the eardrums we have in our heads. The only difference is that katydids have ears on their knees. So I have this beetle and it looks pretty ordinary. I really wish it was something cooler like a rainbow cricket or that giant katydid we just looked at. So I was wondering, what if it was enormous and had these big jaws and really long legs? We can throw some antenna on there, maybe some big juicy eyes. The middle part can have some huge spikes on it. And on the bottom, let's throw this weird, like a tribal pattern tattoo type thing. Okay, let's see what it looks like. Hey, how about that? That looks wonderful. This is a giant saber-toothed longhorned beetle. It's found in South America, but let me show you something that's found all over the world. This is a jar full of remora. They're those weird fish that stick to sharks and whales. But how do they stick? That's a good question. Let's figure it out. So they don't have suction cups on their bellies, like I thought, but what about on the back of their heads? Ah, do you see these folds and flaps? Okay, so when they're underwater, remoras can squeeze those flaps like a muscle, suctioning themselves onto the surface of another animal. And when they release those flaps, they let go. This is the same action that happens in beaver mouths. This is my beaver skull. Now, do you ever look at your beaver skull and wonder what's the deal with this gap in between the front and back teeth? What the heck is going on here? Well, the answer has to do with those sweet beaver cheeks. When beavers are chomping wood, they suck in their cheeks through this gap. That's right there. This creates a seal that blocks off their throat so they can't swallow anything. That way, when they're chomping wood, they don't swallow or choke on any wood chips. And that's why beaver skulls have that gap.