Strange Animals Podcast

• Episode 418: Animals Discovered in 2024

  This week we take a look at some of the many animals that were discovered last year! Further reading: ‘Blob-Headed’ Catfish among New Species Discovered in Peru New Species of Dwarf Deer Discovered in Peru Hylomys macarong, the vampire hedgehog Hairy giant tarantula: The monster among mini tarantulas with 'feather duster' legs Woods Hole Oceanographic Institution and partners discover new ocean predator in the Atacama Trench Never-before-seen vampire squid species discovered in twilight zone of South China The blob headed catfish [photo by Robinson Olivera/Conservation International]: A new mini tarantula [photo by David Ortiz]: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week is the 8th year anniversary of this podcast, so thanks for listening! It’s also our annual discoveries episode, where we’ll learn about a few animals that were discovered last year--in this case, in 2024. Let’s start in Peru, a country in western South America. A 2022 survey of organisms living in the Alto Mayo region was published at the very end of 2024, revealing at least 27 new species and potentially more that are still being studied. One of those new species is a fish called the blob headed catfish. The new fish has been placed in the bristlemouth armored catfish genus, but as you can probably guess from its name, it has a big blobby head and face. Scientists have no idea why it has a blob head. It lives in mountain streams and that’s about all we know about it right now. Another animal found in the same survey is a new mouse. It lives in swampy forests and is semi-aquatic, including having webbed toes. It’s dark gray in color and is probably closely related to the Peruvian fish-eating rat, which is mostly brown in color and was only described in 2020. Another new species from Peru is a type of small deer, called a pudu, that has been named Pudella carlae. It’s one of those “hidden in plain sight” discoveries, because until 2024 it was thought to be the same as the northern pudu that also lives in Ecuador and Colombia. The new deer is only 15 inches tall, or 38 cm, and is dark brownish-orange in color with black legs and face. It only lives in Peru, mostly in high elevations. It’s also the first deer species discovered in the 21st century, although hopefully not the last. While we’re talking about mammal discoveries, we have to talk about the vampire hedgehog just because of its name. It was actually described at the very end of 2023, but it’s such an interesting animal that we’ll say it’s a 2024 discovery. The vampire hedgehog was actually discovered a whole lot earlier than 2023, but no one noticed it was new to science for a long time. A small team of researchers studying soft-furred hedgehogs decided to collect DNA samples from all the museum specimens they could find. One of the specimens was in the archives of the Smithsonian National Museum of Natural History, collected in 1961 but never studied. When the scientists compared its DNA to the other specimens they’d found, it didn’t match up. Not only that, a closer look showed that it had fangs. Naturally, they named it the vampire hedgehog and went searching for living ones. The vampire hedgehog lives in parts of Vietnam and is a member of the soft-furred hedgehogs, also called gymnures, hairy hedgehogs, or moonrats. Instead of spines, moonrats have bristly fur and long noses that make them look like shrews, but hairless tails that make them look like rats. They’re not rodents but are closely related to other hedgehogs. They eat pretty much anything but especially like to eat meat. This includes mice and frogs, along with various invertebrates. As for the vampire hedgehog’s fangs, both males and females have them, but males have bigger fangs. Scientists don’t know yet what the hedgehogs use their fangs for. It could be they help the animals keep a better hold on wiggly prey,

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• Episode 417: The Hoatzin

  I'm a bit under the weather this week, so here's a Patreon episode about a weird bird! Further reading: Hoatzin nestling locomotion: acquisition of quadrupedal limb coordination in birds Show transcript: Welcome to the Patreon bonus episode of Strange Animals Podcast for mid-November, 2019! We’re going to learn about a mystery bird today. When I say mystery bird, I don’t mean that people aren’t sure if it exists. It definitely exists. You can go to South America and look at it if you like, because fortunately it’s not rare or endangered. But scientists aren’t completely sure what it’s related to, because it’s a really weird bird. The hoatzin [pronounced what-seen] is a large bird, over two feet long, or 65 cm. It’s shaped sort of like a pheasant, with a chunky body, long neck and small head, and a long tail made of stiff feathers like a hawk’s. Its face has no feathers and blue skin, it has red eyes, and it has a spiky feather crest on its head. It’s black and chestnut brown with some darker and lighter streaks, and is a softer brown underneath. It’s a really pretty bird, in fact, with a strong bill. But it really doesn’t resemble any other bird alive today. The hoatzin is the only species in its genus, and the only genus in its family, and the only family in its order. It’s basically not really related to any other bird alive today, although in 2012 its genome was sequenced and found to be most closely related to cranes and plovers—but only very distantly. In fact, a 2015 study determined that the hoatzin started evolving separately from other birds 65 million years ago, right after the Cretaceous-Paleogene extinction event that killed off the non-avian dinosaurs. We only have a few fossils of hoatzin ancestors, but they show that it was much more widespread in the past and lived in what is now North America and Europe. But these days it only survives in northern and central South America. It likes swampy areas and forests near rivers or other water. The hoatzin eats plants—specifically leaves and buds, although it also eats some flowers and fruit. And leaves require a lot of digesting before the body can make use of the nutrients. The hoatzin’s digestive system is unlike any other living bird’s, because the hoatzin is a foregut fermenter. Its crop, which most birds only use to store extra food temporarily when the stomach is full, acts as a bacterial fermentation chamber—two chambers, in fact, since it’s divided into two sections. This acts like the rumen of a cow. Its crop is so big it doesn’t have room on its body for big flight muscles, so it’s not a strong flyer. It mostly stays in trees and bushes, eating leaves, flapping its big wings for balance and display, and hanging out with other hoatzins. The hoatzin’s digestive system has a weird side effect. It smells bad. It’s supposed to smell like manure. It’s sometimes called the stinkbird and, fortunately for the hoatzin, almost no one wants to eat it as a result. As you probably know, birds developed from dinosaurs. It’s easy to forget that, since birds have evolved structures like toothless beaks and front legs modified for flight and they no longer have lizard-like tails. But the hoatzin retains something from its dinosaur ancestry that is a startling reminder. The hoatzin is a social bird that lives in small flocks. It breeds during the local rainy season and builds its nest over water when the forest floods due to rain. The female lays two or three eggs, and when the babies hatch, they can climb around in the branches near the nest right away. This means they can hide from predators instead of being helpless in the nest. And the reason a hoatzin chick can climb so well is partly because it has big feet, and partly because it has finger claws on its wings: specifically a thumb claw and one finger claw, which are fully functional and make it look a lot like a fuzzy baby dinosaur.

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• Episode 416: The heaviest tarantula and the bitey-est ant

  Thanks to Siya, Sutton, Owen, and Aksel for suggesting this week's topic, the Goliath birdeater tarantula and the fire ant! Further listening: The TEETH Podcast Further reading: Tropical fire ants traveled the world on 16th century ships The Goliath birdeater tarantula, bigger than some kittens: Fire ants: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week we’re going to talk about two invertebrates, a spider and an insect. Thanks to Siya, Sutton, Owen, and Aksel for suggesting them! We’ll start with the spider, which Siya and Sutton both suggested. It’s the goliath tarantula, also called the goliath birdeater. You know it has to be a big spider if it’s called a birdeater. We’ve talked about it before, but not in a long time. The goliath birdeater is the heaviest spider in the world. If you think of the usual spider, even a big one, it’s still pretty lightweight. Let’s use a wolf spider as an example, which is found just about everywhere in the world. It’s a hunting spider that doesn’t spin a web, and while different species vary in size, the biggest is the Carolina wolf spider found in many parts of North America. A big female can have a legspan of four inches across, or 10 cm, with a body up to an inch and a half long, or 35 mm—but it weighs less than an ounce. That’s barely 28 grams, or just a little heavier than five sheets of printer paper. In comparison, the goliath birdeater tarantula can weigh over 6 ounces, or 175 grams. That’s heavier than a baseball, or two packs of cards. Its legspan can be as much as 12 inches across, or 30 cm with a body length of about 5 inches, or 13 cm. It’s brown or golden in color and lives in South America, especially in swampy parts of the Amazon rainforest. It’s nocturnal and mostly eats worms, large insects, other spiders, amphibians like frogs and toads, and occasionally other small animals like lizards or even snakes. And yes, every so often it will catch and eat a bird, but that’s rare. Birds are a lot harder to catch than worms, especially since the Goliath birdeater lives on the ground, not in trees. Because it’s so large, the goliath looks like it would be incredibly dangerous to humans. It does have fangs and can inflict a venomous bite, but it’s not very strong venom. The danger comes from a very different source, because the goliath birdeater is famous for its urticating spines. Many species of tarantula have special setae, hairlike structures called urticating spines, that can be dislodged from the body easily. If a tarantula feels threatened, it will rub a leg against its abdomen, dislodging the urticating spines. The spines are fine and light so they float upward away from the spider on the tiny air currents made by the tarantula’s legs, and right into the face of whatever animal is threatening it. The spines are covered with microscopic barbs that latch onto whatever they touch. If that’s your face or hands, they are going to make your skin itch painfully, and if it happens to be your eyeball you might end up having to go to the eye doctor for an injured cornea. Scientists who study tarantulas usually wear eye protection. The goliath birdeater tarantula is considered a delicacy in northeastern South America. People eat it roasted. Apparently it tastes kind of like shrimp. Next, Owen and Aksel wanted to learn about fire ants. I couldn’t believe that we’ve never talked about fire ants before! Fire ant is the name for any of the more than 200 species in the genus Solenopsis, but it’s typically used to refer to the species Solenopsis invicta. It’s native to tropical South America but has been introduced to parts of North America, Australia, China, Taiwan, India, Africa, and many other places where the climate is tropical or sub-tropical. The fire ant initially became so invasive due to Spanish galleons in the 16th century, which carried trade goods around the world.

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• Episode 415: Animals with Names

  This week we're going to learn about some animals that seem to have individual names! Further reading: Bottlenose dolphins can use learned vocal labels to address each other How Do Dolphins Choose Their Name? Vertical transmission of learned signatures in a wild parrot Baby Parrots Learn Their Names from Their Parents Study: African Elephants Address Each Other With Name-Like Calls Marmoset Monkeys Use Names to Communicate with Each Other The green-rumped parrotlet (photo by Rick Robinson, taken from this site): Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week we’re going to learn about some animals that seem to be using names to refer to other individuals or themselves. Let’s start with bottlenose dolphins, because they’re well-studied and scientists have known about this particular aspect of their society for over a decade. Every bottlenose dolphin has a signature whistle that identifies it to other dolphins. The signature whistles can be complex and the dolphin may add or change details to indicate its mood or other information. It’s not precisely a name in the way humans would think of it, but it is an identifier. The dolphin creates its own signature whistle when it’s young. Some dolphins pattern their whistles on their mother’s signature whistle, while others mimic their siblings or friends. Some seem to pattern theirs on a distant acquaintance, which sounds to me like they just like something about an unusual whistle and decide to incorporate it into their own whistle. As dolphins grow up, females typically don’t change their whistles, but males often do. Male dolphins often pair up together and remain bonded, and a pair may change their signature whistles to be similar. When a dolphin is trying to find a friend it can’t see, it will mimic that friend’s signature whistle. If a mother can’t see her calf and is worried, she’ll do the same, and her calf will answer by repeating its signature whistle. A lost calf will imitate its mother’s whistle. But it’s even more complicated than it sounds, because a group of dolphins who get together to forage may choose a shared whistle that the whole group uses. This helps them coordinate their behaviors to work together. Each member of the group uses a slightly different version of the group whistle, which means that each member can identify who’s speaking. Other cetaceans seem to use a similar kind of name. Sperm whales, for instance, have a unique click sequence that they use to announce themselves when approaching other whales. The signature clicks always appear at the beginning of a sequence and don’t vary. Bottlenose dolphins and many other cetaceans are extremely social animals. So are parrots. Studies of parrot calls indicate that parrots appear to have signature calls that they use the same way as dolphins do, to identify themselves to other parrots and as a way for other parrots to call for them. A study of wild green-rumped parrotlets in Venezuela discovered that the birds give a unique signature call to each baby while it’s still in the nest, and the baby continues to use its call its whole life, often with small changes. The study set up video cameras to monitor 16 nests of a large wild population of the parrots. The population has been well studied and is used to using nesting tubes that scientists have set up for them. This makes it easier for the scientists to monitor nesting behaviors. In this case, to test whether the names had something to do with genetics or not, the scientists sneakily moved half of the eggs from one nest to another, so that half the parents unknowingly raised some chicks that weren’t actually related to them. Despite the egg switcharoo, all the chicks were given names that were similar to the parents’ signature calls. The parents started using a specific signature call soon after the eggs hatched, and the babies started imitating it.

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• Episode 414: Two Marvelous Frogs

  Thanks to Eilee and Alexis for their suggestions this week, two amazing frogs! Further reading: Paradoxical frog: The giant tadpole that turns into a little frog Fungus is wiping out frogs. These tiny saunas could save them. How to build a frog sauna The paradoxical frog [photo by Mauricio Rivera Correa - http://calphotos.berkeley.edu, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=6703905]: The Vietnamese mossy frog [photo by H. Zell - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=81804225]: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. Let’s start 2025 off right with an episode about frogs! Thanks to Alexis and Eilee for their suggestions. Let’s start with Eilee’s suggestion, the paradoxical frog. The paradoxical frog is a type of tree frog that lives in South America. Like other frogs, it likes ponds and shallow lakes. Some individuals are green and some are brown, and a frog may have darker stripes or splotches, or might just be plain. The tadpoles eat algae and other tiny food, while the adults eat insects. As with most frogs, the paradoxical frog hatches into a larval stage called a tadpole or pollywog, which is fully aquatic. It later metamorphoses into its adult form as a frog. Most tadpoles start out very small and grow larger, then metamorphose into a juvenile frog which then grows to fully adult size. But while the paradoxical frog’s tadpole starts out small, it can grow to as much as 11 inches long, or 28 centimeters! It’s the largest tadpole in the world as far as we know. So how big is the adult frog if the tadpole is so enormous? About 3 inches long, or 7.5 cm, from snout to vent. That’s why it’s called the paradoxical frog, because a paradox is something that seems contradictory to expectations. Instead of the ordinary way of things, where a small tadpole grows into a bigger frog, in this case a big tadpole grows into a smaller frog. It’s sometimes called the shrinking frog. One interesting detail is that not all of the tadpoles are that big. If a female lays her eggs in a small body of water that’s likely to dry up, or that doesn’t have a lot of food available, or if there are a lot of predators in the water, the tadpole metamorphoses quickly and doesn’t grow very big. But if the tadpole is in a better location it matures much more slowly, which allows it to reach much larger size before metamorphosing. I should also mention that the 11-inch-long tadpole that is the largest ever measured was actually raised in captivity. In the wild, the largest paradoxical frog tadpole ever measured was 6 ½ inches long, or almost 17 cm. That’s still really big, but not that ridiculously big. But the confusing thing is that the tadpole is big and bulky, up to four times the size of the adult frog. Where does all that mass go after it transforms? Early scientists who learned about the paradoxical frog wondered the same thing. They were so confused that they suggested that the frog actually came first and later metamorphosed into the tadpole, which then metamorphosed into a fish. But the main reason the tadpole is so long is its tail. When it metamorphoses into a frog, it absorbs the tail and therefore appears to shrink. The bulkiness of the tadpole’s body matches the bulkiness of the frog’s body. And unlike most frogs, which metamorphose into juvenile frogs that still have some growing to do, the paradoxical frog metamorphoses into a completely adult frog. It’s as big as it will ever get and fully mature, ready to mate and lay eggs. Next, Alexis wanted to learn about the Vietnamese mossy frog. It lives in parts of Vietnam, Laos, and other nearby areas. It prefers mountainous rainforests and the female often chooses to lay her eggs in a tree hollow or even a rock cavity where water has collected. Instead of laying her eggs in the actual water, though, she lays them on rocks or branches above the water.

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