Strange Animals Podcast

• Episode 463: The Big Fish Episode

  It's an episode just absolutely full of fish! Thanks to Arthur, Yuzu, Jayson, Kabir, Nora, Siya, Joel, Elizabeth, Mac, Ryder, Alyx, Dean, and Riley for their suggestions this week! Further reading: Study uncovers mechanics of machete-like 'tail-whipping' in thresher sharks Business end of a sawfish: Giant freshwater stingray! The frilled shark looks like an eel: The frilled shark's teeth: The thresher shark and its whip-like tail [photo by Thomas Alexander - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=50280277]: The Halmahera epaulette shark, looking a little bit like a long skinny koi fish [photo by Mark Erdmann, California Academy of Sciences, Attribution, https://commons.wikimedia.org/w/index.php?curid=30260864]: A mudskipper, which is a fish even though it kind of looks like a weird frog [photo by Heinonlein - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=44502355]: The red-lipped batfish wants a big kiss: The male blue groper is very blue [photo by Andrew Harvey, some rights reserved (CC BY) - https://www.inaturalist.org/photos/62196538, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=157789928]: The giant oarfish is very long: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week we have a big fish episode! I mean, it’s a big episode about a lot of different fish, not necessarily fish that are big—although some of them sure are! Thanks to Arthur, Yuzu, Jayson, Kabir, Nora, Siya, Joel, Elizabeth, Mac, Ryder, Alyx, Dean, and Riley. I told you this is a big fish episode. Let’s jump right in with a fish suggested by Jayson, the sawfish. There are five species of sawfish alive today. The smallest can still grow over 10 feet long, or 3 meters, while the biggest species can grow over 20 feet long, or 6 meters. The largest sawfish ever reliably measured was 24 feet long, or 7.3 meters. The sawfish lives mostly in warm, shallow ocean waters, usually where the bottom is muddy or sandy. It can also tolerate brackish and even freshwater, and will sometimes swim into rivers and live there just fine. The sawfish is a type of ray, and rays are most closely related to sharks. Like sharks, rays have an internal skeleton made of cartilage instead of bone, but they also have bony teeth. You can definitely see the similarity between sharks and sawfish in the body shape, although the sawfish is flattened underneath, which allows it to lie on the ocean floor. There’s also another detail that helps you tell a sawfish from most sharks: the rostrum, or snout. It’s surprisingly long and studded with teeth on both sides, which makes it look like a saw. The teeth on the sawfish’s saw are actual teeth. They’re called rostral teeth and the rostrum itself is part of the skull, not a beak or a mouth. It’s covered in skin just like the rest of the body. The sawfish’s mouth is located underneath the body quite a bit back from the rostrum’s base, and the mouth contains a lot of ordinary teeth that aren’t very sharp. Since the sawfish has plenty of teeth in its mouth, you may be wondering how and why it also has extra teeth on both sides of its saw. It’s because the rostral teeth evolved from dermal denticles. Dermal denticles look like scales but they’re literally teeth, they’re just not used for eating. Sharks have them too, along with some other fish. In the case of the sawfish, the rostral teeth grow much larger than an ordinary dermal denticle, and stick out sideways. Both the rostrum and the head are packed with electroreceptors that allow the sawfish to sense tiny electrical charges that animals emit as they move. This might mean a school of fish swimming through muddy water, or it might mean a crustacean hiding in the sand. The sawfish sometimes uses its rostrum to dig prey out of the sand, but it also uses it to slash at fish or other animals.

  --------  

  20:31

  --------

  20:31
• Episode 462: Cryptic Coloration

  Thanks to Måns, Sam, Owen and Askel for this week's suggestions! Further reading: Shingleback Lizard What controls the colour of the common mānuka stick insect? The mossy leaf-tailed gecko has skin flaps that hide its shadow. There's a lizard in this photo, I swear! [photo by Charles J. Sharp - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=92125100]: A shingleback lizard, pretending it has two heads: The beautiful wood nymph is a beautiful moth but also it looks like a bird poop: The Indian stick insect (photo by Ryan K Perry, found on this page): The buff tip moth mimics a broken-off stick. This person has a whole handful of them: A cuttlefish can change colors quickly [photo by Σ64 - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=77733806]: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week we’re going to talk about a few types of camouflage, a suggestion by Måns, and we’ll also talk about some camouflaged animals suggested by Sam, Owen and Aksel, Dylan, and Nina. There are lots of types of camouflage, not all of it visual in nature. Back in episode 191 we talked about some toxic moths that generate high-pitched clicks that bats hear, recognize, and avoid. Naturally, some non-toxic moths also generate the same sounds to mimic the toxic moths. Måns specifically suggested cryptic coloration, also called crypsis. It’s a type of camouflage that allows an animal to blend into their surroundings, which can involve multiple methods. Some animals have cryptic coloration mainly along the edges of the body, to defeat a skill many predators use called edge detection. A lot of amphibians and reptiles have patches surrounded by an outline, with dark patches having a darker outline and light patches having a lighter outline. This acts as disruptive camouflage, hiding the outline of an animal’s body as it moves around. Some animals take this camouflage even further, with a way to hide their own shadow. This is the case with the mossy leaf-tailed gecko, which is native to the forests of eastern Madagascar. It can grow up to 8 inches long, or 20 cm, not counting its tail, and it’s nocturnal. Its tail is flat and broad, sort of shaped like a leaf, but it doesn’t disguise itself as a leaf. The mossy leaf-tailed gecko has a complicated gray and brown pattern that looks like tree bark, and it can change its coloration a little bit to help it blend in even more. At night it’s well hidden in tree branches as it climbs around looking for insects, but in the day it needs to hide really well to avoid becoming some other animal’s snack while it’s sleeping. It does this by finding a comfortable branch and flattening its body and tail against it so that it just looks like another part of the branch. But to make it even more hidden, it has a flap of skin along its sides that wraps even farther around the branch. Not only do these skin flaps hide its edges, it hides its shadow, since the flaps are really flat and there’s no curved edge of a lizard belly pressed against a branch that a predator might notice. The most common kind of cryptic coloration is called countershading, and it’s so common that you might not even have noticed it although you see it almost every time you see a fish, amphibian, reptile, and many birds and mammals. Countershading is an animal that’s darker on top and lighter underneath, like a brown mouse with a white belly. It’s even found in some insects and other invertebrates. Countershading is another way to hide a shadow. If a dolphin, for instance, was gray all over, its underside would look darker because of shadows, since sunlight shines down from the sky and makes shadows underneath the body. That would make its body shape look rounder, meaning it stands out more and a predator would notice it more easily. But most dolphins are pale gray or even white underneath.

  --------  

  17:07

  --------

  17:07
• Episode 461: Therizinosaurus and Its CLAWS

  Further reading: Study: Giant Therizinosaurs Used Their Meter-Long, Sickle-Like Claws for Display Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. I am delighted to report that Therizinosaurus lived in what is now Mongolia in Central Asia, in the Gobi Desert. 70 million years ago, the land wasn’t a desert at all but a forest with multiple rivers and streams flowing through it. Lots of other dinosaurs and birds lived in the area, including a tyrannosaurid called Tarbosaurus that was probably the only predator big enough to kill Therizinosaurus. When the first Therizinosaurus fossils were discovered in the 1950s, they were initially thought to belong to a type of giant turtle. Later it was reclassified as a sauropod relation, not a turtle. These days, we know for sure it’s not a turtle and we’re pretty sure it’s not anything like a sauropod. The Therizinosaurus fossils found so far are incomplete. All we have are some ribs, one hind foot, and mostly complete arms and hands. We don’t have any parts of the skull or any vertebrae, so paleontologists still have a lot of questions about what Therizinosaurus looked like and how it lived, although we have more complete specimens of some of its close relations to help scientists make good guesses. Luckily we have its hands, because its claws are enormous. Therizinosaurus had claws bigger than any other dinosaur known. Therizinosaurus was a big dinosaur overall, with an estimated length of 33 feet, or 10 meters, although until a more complete specimen is discovered we can’t know for sure how big it really was. It may have stood up to 16 feet tall, or 5 meters, and walked on its hind legs. It’s classified as a theropod these days, a group that includes famous dinosaurs like T. rex and Spinosaurus, but it wasn’t closely related to those big fast meat-eaters. Most paleontologists think Therizinosaurus ate plants, but again, we don’t know for sure since we don’t have any of its teeth to examine. Its closest relatives were herbivorous but its immediate ancestors were carnivorous. If Therizinosaurus was a plant-eater, why did it have such enormous claws? Its claws were seriously terrifying! Its arms were big and strong in general, measuring about 8 feet long, or 2.5 meters, including long, slender fingers, and the claws measured over three feet long! That’s more than a meter long. If the claws were covered with a keratin sheath, which is probable, they would have been even longer when Therizinosaurus was alive. They were relatively thin and straight with a curve at the end. There are many reasons why an animal develops big claws. Predators need claws to help grab prey or tear meat into pieces, or an animal may need big claws to help it dig or climb trees. Claws are also great for defense. Some animals use claws to grab tree branches and bend them closer to the animal’s mouth, which is something that giant ground sloths probably did, at least sometimes. The new study published in February 2023 examined the claws of Therizinosaurus and lots of other dinosaurs to learn how strong they were. The claws were 3D scanned, and then the scans were used in various models that measured the stress placed on each claw in various different activities. The study discovered that the claws of different dinosaurs were strong in different ways depending on what they were used for, which wasn’t a surprise. What was a surprise was that Therizinosaurus’s claws were weak no matter which model the scientists used. In other words, Therizinosaurus probably didn’t use its claws to fight other dinosaurs unless it just had to, because they would break too easily. It wouldn’t have dug with its claws or even used them to hook branches down closer to its mouth. As far as we can tell, its claws were basically useless. But obviously, Therizinosaurus used its claws for something or it wouldn’t have evolved to have such gigantic claws.

  --------  

  7:42

  --------

  7:42
• Episode 460: Blue Blobs and Graveyard Snakes

  Further reading: Mysterious ‘blue goo’ at the bottom of the sea stumps scientists Three new species of ground snakes discovered under graveyards and churches in Ecuador Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. I’ve come down a cold this week, and while I’m feeling better, it is settling into my chest as usual and I’m starting to cough. Since I’m still recovering and need to be in bed instead of sitting up researching animals, and since my voice is already sounding a little rough, here’s a Patreon episode this week instead of a regular episode. I had been planning to run old Patreon episodes for a few weeks in December so I could have some time off for the holidays, and those were already scheduled, so I just moved one of those episodes up to use this week instead. This is a Patreon episode from October of 2022, where we talked about two very slightly spooky animal discoveries. We’ll start with a suggestion from my brother Richard, about a strange newly discovered creature at the bottom of the ocean. On August 30, 2022, the NOAA Ocean Exploration research team was off the coast of Puerto Rico. That’s in the Caribbean, part of the Atlantic Ocean. The expedition was mostly collecting data about the sea floor, including acoustic information and signs of climate change and habitat destruction. Since the Caribbean is an area of the ocean with high biodiversity but also high rates of fishing and trawling, the more we can learn about the animals and plants that live on the sea floor, the more we can do to help protect them. When a remotely operated vehicle dives, it sends video to a team of scientists who can watch in real time and control where the rover goes. On this particular day, the rover descended to a little over 1,300 feet deep, or around 407 meters, when the sea floor came in view. Since this area is the site of an underwater ridge, the sea floor varies by a lot, and the rover swam along filming things and taking samples of the water and so forth, sometimes as deep as about 2,000 feet, or 611 meters. The rover saw lots of interesting animals, including fish and corals of various types, even a fossilized coral reef. Then it filmed something the scientists had never seen before. It was a little blue blob sitting on the sea floor. It wasn’t moving and it wasn’t very big. It was shaped roughly like a ball but with little points or pimples all over it and a wider base like a skirt where it met the ground. And it was definitely pale blue in color. Then the rover saw more of the little blue blobs, quite a few of them in various places. The scientists think it may be a species of soft coral or possibly a type of sponge, possibly even a tunicate, which is also called a sea squirt. All these animals are invertebrates that don’t move, which matches what little we know about the blue blob. The rover wasn’t able to take a sample from one of the blue blobs, so for now we don’t have anything to study except the video. But we know where the little blue blobs are, so researchers hope to visit them again soon and learn more about them. Next, let’s return to dry land and learn about some newly discovered snakes. In fact, we’re not just on dry land, we’re way up high in the Andes Mountains in South America, specifically in some remote villages in Ecuador. A teacher named Diego Piñán moved to the town of El Chaco in 2013, and he started noticing dead snakes on the road that he didn’t recognize. He also realized that people were killing the snakes on purpose. A lot of people are afraid of snakes, so Piñán made sure to teach his students about them so they would learn that most snakes aren’t dangerous. He also kept the dead snakes he found and preserved them in alcohol so he could figure out later what species they were. But he never could figure it out. Then a scientist named Alejandro Arteaga assembled a team to study the animals found in remote areas of the...

  --------  

  5:58

  --------

  5:58
• Episode 459: Strange Little Dolphins

  Thanks to Alexandra, Jayson, and Eilee for their suggestions this week! Further reading: Scientists have discovered an ancient whale species. It may have looked like a mash-up of ‘a seal and a Pokémon’ The nomenclatural status of the Alula whale Field Guide of Whales and Dolphins [1971] The little Benguela dolphin [photo taken from this site]: The spinner dolphin almost looks like it has racing stripes [photo by Alexander Vasenin - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=25108509]: The Alula whale, which may or may not exist: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week let’s learn about some whales and dolphins, including an ancient whale and a mystery whale, all of them really small. Thanks to Alexandra, Eilee, and Jayson for their suggestions! Let’s start with an ancient whale, suggested by Jayson. The genus Janjucetus has been known since its first species was described in 2006, after a teenage surfer in Australia discovered the fossils in the late 1990s. It grew to about 11 feet long, or 3.5 meters, and lived about 25 million years ago. So far it’s only been found around Australia. But much more recently, just a few months ago as this episode goes live, a new species was described. That’s Janjucetus dullardi, also found in Australia along the same beach where the first Janjucetus species was found, and dating to around the same time period. We don’t know a lot about the newly described whale, since it’s only known from some teeth and partial skull. Scientists think the individual was a juvenile and estimate it was only around 6 feet long when it died, or 2.8 meters. Small as it was, it would have been a formidable hunter when it was alive. Its broad snout was shaped sort of like a shark’s and it had strong, sharp teeth and large eyes. Because it was an early whale, it wouldn’t have looked much like the whales alive today. It might even have had tiny vestigial back legs. Its eyes were huge in proportion to its head, about the size of tennis balls, and it probably relied on its eyesight to hunt prey because it couldn’t echolocate. Its serrated teeth and strong jaws indicate that it might have hunted large animals, but some scientists suggest it could also filter feed the same way a crabeater seal does. Modern crabeater seals have similar teeth as Janjucetus, as do a few other seals. The projections on its teeth interlock when the seal closes its mouth, so to filter feed the seal takes a big mouthful of water, closes its teeth, and uses its tongue to force water out through its teeth. Amphipods and other tiny animals get caught against the teeth and the seal swallows them. If Janjucetus did filter feed, it probably also hunted larger animals. Otherwise its jaws wouldn’t have been so strong or its teeth so deeply rooted. But Janjucetus wasn’t related to modern toothed whales. While it wasn’t a direct ancestor of modern baleen whales, it was part of the baleen whale’s family tree. Baleen whales, also called mysticetes, have baleen plates made of keratin instead of teeth. After the whale fills its mouth with water, it closes its jaws, pushes its enormous tongue up, and forces all that water out through the baleen. Any tiny animals like krill, copepods, small squid, small fish, and so on, get trapped in the baleen. It’s just like the crabeater seal, but really specialized and way bigger. Whether or not Janjucetus could and did filter feed doesn’t really matter, because the fact that it’s an ancestral relation of modern baleen whales but it had teeth helps us understand more about modern whales. Next, Eilee wanted to learn about the Benguela [BEN-gull-uh] dolphin, also called Heaviside’s dolphin. It lives only off the southwestern coast of Africa, and it’s really small, only a little over 5 and a half feet long at the most, or 1.7 meters. It’s dark gray with white markings,

  --------  

  11:49

  --------

  11:49

More Science podcasts

Trending Science podcasts

About Strange Animals Podcast