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Strange Animals Podcast

Strange Animals Podcast

De: Katherine Shaw
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A podcast about living, extinct, and imaginary animals! Ciencia Ciencias Biológicas Historia Natural Naturaleza y Ecología
Episodios
  • Episode 473: Blue Frogs
    Feb 23 2026
    This week let’s learn about some blue frogs! Further reading: Scientists make chance discovery of rare blue skin mutation in Kimberley magnificent tree frog White’s True-Blue Green Tree Frog Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. When most of us draw a frog, we reach for the green markers, because most frogs are green. That’s true of the magnificent tree frog, also called the splendid tree frog, which is fairly common in the Kimberley region of western Australia. It grows just over 4 inches long, snout to vent, or about 10 and a half cm, and lives in rocky areas. It spends the day hiding in rock crevices, holes in trees, or sometimes in people’s houses, and it comes out at night to hunt for insects and other small invertebrates. From the name, you might imagine that this is an especially pretty frog, and it is. It’s mostly bright green on top and yellow to white underneath, and it has tiny yellow spots on its head and back. It looks like it has an olive green cap on its head, but that’s actually a large parotoid gland, a skin gland common in frogs and toads that secretes neurotoxins. Most frogs don’t have a parotoid gland at all, and in ones that do you typically will barely notice it, but the magnificent tree frog’s covers the entire top of its head almost to its nostrils and down onto its back. The skin color of a frog depends on its chemical makeup. Melanophores make black and brown colors, xanthophores make yellow. Blue is different, since it’s not a color that’s actually found in skin pigments. Instead, a green frog’s skin contains iridophores that reflect blue light waves, the same way a bird’s feathers show blue. The combination of yellow and blue makes green, and the addition of melanophore pigments determine how dark or bright the green is. In July of 2024, two land managers were working in the Charnley River-Artesian Range Wildlife Sanctuary. They were in a workshop when one of them noticed a magnificent tree frog sitting on a bench, not that unusual of an occurrence–except that this frog wasn’t green. It was blue! The condition is called axanthism, where the yellow pigments in the frog’s skin don’t show up the way they should. Most of them time axanthism in frogs means the animal has little patches of blue or bluish coloration, but this specific frog was blue just about everywhere it should have been green. Its parotoid gland was still olive green and it had yellow on its feet, but mainly it was a very attractive dark blue. The land managers were stunned. They took photos and sent them to pretty much everyone, and frog experts and ecologists hurried to examine the blue frog. But they decided not to keep the frog in captivity. It was released back into the wild to live out its blue froggy life normally. Some frogs are naturally blue, like some poison dart frogs of South America. The blue poison dart frog’s legs are dark blue and its body a lighter blue with black spots. It grows less than two inches long, or about 4.5 cm. Poison dart frogs collect toxins in their bodies from some of the toxic insects they eat, and the bright coloration signals to predators that this frog will make you really sick if you eat it. Axanthism is rare but not all that uncommon in frogs. About the same time that the blue magnificent tree frog was hopping into the workshop in Australia, two little girls playing around a pond in Nova Scotia, Canada found a teal-blue frog. Ironically, the frog is actually called the green frog and it’s ordinarily a dark olive-green all over. The girls named the frog Bluey and released it back into the pond. Another blue green frog was found in New Hampshire, in the United States, also in July 2024. In June 2024 a forest ranger spotted a northern leopard frog in Washington state that had splotches of light blue on its head and back. In May of 2024 a light blue Japanese tree frog was found by a couple on a walk. The Australian green tree frog is closely related to the magnificent tree frog, although it doesn’t have a parotoid gland hat. It’s mostly green with a white or pale gray belly. It’s sometimes called the dumpy tree frog because it’s a little chonk. Actually, for a frog it’s a pretty big chonk, up to 4 and a half inches long, or over 11 cm. It’s also sometimes called White’s tree frog after John White, who described it in 1790. It was the first Australian frog that was ever scientifically described. But that leads us to a little mystery. John White named the frog Rana caerulea. Its current scientific name is Ranoidea caerulea. But “caerulea” refers to the color blue, not green, as in cerulean blue. John White collected the frog in 1788, preserved it in alcohol, and finally described it two years later. He refers to it in his writing as a blue frog and the illustration accompanying it shows frogs that are actually blue. But this frog is supposed to be green! The main suggestion for why ...
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    7 m
  • Episode 472: The Hafgufa
    Feb 16 2026
    Further reading: Parallels for cetacean trap feeding and tread-water feeding in the historical record across two millennia Haggling over the Hafgufa Many renditions of the hafgufa/aspidochelone: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. Back in the olden days, as much as 1700 years ago and probably more, up through the 14th century or so, various manuscripts about the natural world talked about a sea monster most people today have never heard of. In ancient Greek it was called aspidochelone, contracted to aspido in some translations, while in Old Norse it was called the hafgufa. But it seemed to be the same type of monster no matter who was writing about it. The animal was a fish, but it was enormous, big enough that it was sometimes mistaken for an island. When its jaws were open they were said to be as wide as the entrance to a fjord. A fjord is an inlet from the sea originally formed by glaciers scraping away at rocks, and then when the glaciers melted the sea filled the bottom of what was then a steep valley. I’m pretty sure the old stories were exaggerating about the sea monster’s mouth size. The sea monster ate little fish, but it caught them in a strange way. It would open its mouth very wide at the surface of the water and exude a smell that attracted fish, or in one account it would regurgitate a little food to attract the fish. Once there were lots of little fish within its huge mouth, it would close it jaws quickly and swallow them all. Generally, any sea monster that’s said to be mistaken for an island was inspired by whales, or sometimes by sea turtles. The hafgufa is actually included in an Old Norse poem that lists types of whales, and the aspidochelone was considered to be a type of whale even though the second part of its name refers to a sea turtle. So whatever this sea monster was, we can safely agree that it wasn’t a fish, it was a whale. Up until just a few centuries ago people thought whales were fish because of their shape, but we know now that they’re mammals adapted to marine life. But the hafgufa’s behavior is really weird and doesn’t seem like something a whale would do. We’ve talked about skim feeding before, where a baleen whale cruises along at the surface with its mouth held open, until it’s gathered enough food in its mouth and can swallow it all at once. But whales aren’t known to hold their mouths open at the surface of the water and just sit there while fish swim in. At least, they weren’t known to do this until 2011. In 2011, marine biologists studying humpback whales off Canada’s Vancouver Island in North America observed some of the whales catching herring and other small fish in an unusual way. The whales would remain stationary in the water, tails straight down with the head sticking up partly out of the water. A whale opened its mouth very wide and didn’t move until there were a lot of fish in its mouth, which it then swallowed. Soon after, another team of marine biologists studying Bryde’s whales in the Gulf of Thailand in South Asia observed the same activity when the whales were feeding on anchovies at the surface of the water. The term for this activity is called trap feeding or tread-water feeding, and at first the scientists thought it was a response to polluted water that had caused the fish to stay closer to the surface. But once the two teams of scientists compared notes, they realized that it didn’t appear to have anything to do with pollution. Instead, it’s probably a way to gather food in a low-energy way, especially when there isn’t a big concentration of fish in any particular spot, and when researchers remembered the story of the hafgufa, they realized they’d found the solution to that mystery sea monster. The only question was whether the accounts were accurate that the hafgufa emitted a smell or regurgitated food to attract fish. Further observation answered that question too, and it turns out that yes, the old stories were at least partially right. The smell has been compared to rotten cabbage, but it isn’t emitted by the whale on purpose. It’s a smell released when phytoplankton is eaten in large numbers, whether by fish or whales or something else, and it does attract other animals. As for the regurgitation, this is always something that happens to some degree when a baleen whale feeds. The whale fills its mouth with water that contains the fish and other small animals it eats, and it presses its huge tongue upwards to force the water through its baleen, which acts as a sieve. Whatever’s left in its mouth after the water is expelled, it swallows. But baleen is tough and fish are small and delicate in comparison. Often, fish and other small animals get squished to death against the baleen, and parts of them are expelled with the water. This creates a sort of yucky slurry that could be interpreted as a whale regurgitating food to attract more fish. The scientists ...
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    8 m
  • Episode 471: Mystery Larvae
    Feb 9 2026
    Further reading: I Can Has Mutant Larvae? 200-Year-Old ‘Monster Larva’ Mystery Solved ‘Snakeworm’ mystery yields species new to science Hearkening back to the hazelworm Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. A few weeks ago when I was researching big eels, I remembered the mystery eel larva we talked about back in episode 49, and that led me down a fun rabbit hole about other mystery larvae. Let’s start with that eel larva. Eel larvae can be extremely hard to tell apart, so as a catchall term every eel larva is called a leptocephalus. They’re flattened side to side, which is properly referred to as laterally compressed, and transparent, shaped roughly like a slender leaf, with a tiny head at the front. Depending on the species, an eel may remain in its larval form for more than a year, much longer than most other fish, and when it does metamorphose into its next life stage, it usually grows much longer than its larval form. For instance, the larvae of conger eels are only about 4 inches long, or 10 cm, while an adult conger can grow up to 10 feet long, or 3 meters. On January 31, 1930, a Danish research ship caught an eel larva 900 feet deep, or about 275 meters, off the coast of South Africa. But the larva was over 6 feet long, or 1.85 meters! Scientists boggled at the thought that this larva might grow into an eel more than 50 feet long, or 15 meters, raising the possibility that this unknown eel might be the basis of many sea serpent sightings. The larva was preserved and has been studied extensively. In 1958, a similar eel larva was caught off of New Zealand. It and the 1930 specimen were determined to belong to the same species, which was named Leptocephalus giganteus. In 1966, two more of the larvae were discovered in the stomach of a western Atlantic lancet fish. They were much smaller than the others, though—only four inches and eleven inches long, or 10 cm and 28 cm respectively. Other than size, they were pretty much identical to Leptocephalus giganteus. The ichthyologist who examined them determined that the larvae were probably not true eels at all, but larvae of a fish called the spiny eel. Deep-sea spiny eels look superficially like eels but aren’t closely related, and while they do have a larval form that resembles that of a true eel, they’re much different in one important way. Spiny eel larvae grow larger than the adults, then shrink a little when they develop into their mature form. The six-foot eel larva was actually a spiny eel larva that was close to metamorphosing into its adult form. Not everyone agrees that Leptocephalus giganteus is a spiny eel. Some think it belongs to the genus Coloconger, also called worm eels, which are true eels but which have large larvae that only grow to the same size as adults. But worm eels don’t grow much bigger than about two feet long, or 61 cm. If the mystery larvae does belong to the genus Coloconger, it’s probably a new species. Until scientists identify an adult Leptocephalus giganteus, we can’t know for sure. Another mystery larva is Planctosphaera pelagica, which sits all alone in its own class because the only thing it resembles are acorn worms, but scientists are pretty sure it isn’t the larva of an acorn worm. It’s not much to look at, since the larva is just a little barrel-shaped blob that grows about 25 mm across. This sounds small compared to the eel larva we just discussed, but it’s actually quite large compared to similar larvae. Acorn worm larvae are usually only about a millimeter long. Planctosphaera has been classified as a hemichordate, which are related to echinoderms but which show bilateral symmetry instead of radial symmetry. Hemichordates are also closely related to chordates, which include all vertebrates. They’re marine animals that resemble worms but aren’t worms, so it’s likely that Planctosphaera is also wormlike as an adult. Planctosphaera isn’t encountered very often by scientists. It has limited swimming abilities and mostly floats around near the surface of the open ocean, eating tiny food particles. One suggestion is that it might actually be the larva of a known species, but one where an occasional larva just never metamorphoses into an adult. It just grows and grows until something eats it. So far, attempts to sequence DNA from a Planctosphaera hasn’t succeeded and attempts to raise one to maturity in captivity hasn’t worked either. Some people have estimated that an adult Planctosphaera might be a type of acorn worm that can grow nine feet long, or 2.75 meters, which isn’t out of the realm of possibility. The largest species of acorn worm known is Balanoglossus gigas, which can grow almost six feet long, or 1.8 meters, and not only is it bioluminescent, its body contains a lot of iodine, so it smells like medicine. It lives in mucus-lined burrows on the sea floor. Another mystery larva is Facetotecta, which have been found in ...
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Strange Animals Podcast is always entertaining and informative, fantastic for families. Highly recommended for homeschooling, too.

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I loved it very entertaining would recommend if you love animal and want to learn more.

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