Monthly Archives: September 2017

Episode 034: Saber-Toothed Animals

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This week we’ve got a heaping helping of animals with big pointy teeth! Whether you spell it saber or sabre, you don’t want teeth of that description biting you.

Smilodon is the best saber-toothed cat:

Thylacosmilus’s weird chin bone:

Thylacosmilus might have looked something like this when alive:

Kolponomos might have looked something like this when alive:

And the sabertooth fish is still alive!

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

For this week’s episode, we’re looking at saber-toothed animals. The animal people generally think of as THE saber-tooth cat, or saber-tooth tiger, is Smilodon fatalis. Smilodon and its relatives were members of the feline family, although not very closely related to the big and little cats living today. We have a whole bunch of Smilodon fossils, many from the La Brea tar pits in California.

Smilodon was probably descended from a saber-tooth cat called Megantereon, which lived in North America, Eurasia, and Africa. It might have still been around only half a million years ago, was definitely around as recently as 2.5 million years ago, definitely around as long as 4.5 million years ago, and recent finds have been tentatively dated to 7 million years ago. So Megantereon was a very successful animal. It was stocky with strong forelimbs and neck, with long upper canines—not as big as Smilodon’s, but certainly saber-toothed. It wasn’t a giant cat, probably close to a jaguar in size, with males probably being around 5 or 6 feet long (or around 1.5 meters) not including the tail and a little over 2 feet high at the shoulder, or 72 cm. It probably killed its prey by leaping on it and biting its throat.

Megantereon probably acted a lot like a leopard, including climbing trees, but its descendant, Smilodon, was too heavy for tree-climbing. Smilodon was a big, tough kitty about the size of a modern lion. It lived in North America, and migrated into South America at some point too. It probably looked more like a bear than a cat since it was stocky, heavily muscled, and had a broad head and jaws that could open much wider than modern cats’.

Smilodon cubs didn’t have saber teeth. A cub only started growing its big teeth when it was around a year and a half old, and by around three years old the fangs were fully grown, about 7” long or 18 cm. Very few remains of young Smilodons have been found in the La Brea tar pits, so researchers think cubs were mostly fed and cared for by their mother until they had fully grown fangs and had learned to use them.

For a long time researchers thought Smilodon lived in forested areas, but recent studies show that it probably preferred open areas. One 2016 study compared carbon and nitrogen isotopes found in collagen samples from bones of Smilodon and other predators with those of prey animals in South America to find out what they were eating. It turns out that Smilodon ate a lot of Megatherium and other giant ground sloths, as well as a camel-like ungulate called Macrauchenia. There’s even some evidence that Smilodon may have hunted in family groups. Overall, the finding suggests that Smilodon lived a lot more like modern lions do than like other big cats.

The first Smilodon fossils found date to around 2.5 million years ago, but remains found in Florida dated to 5 million years ago have recently been described as a related saber-toothed cat. Smilodon lived until only 10,000 years ago at the end of the Pleistocene. It preyed on ice age megafauna and researchers think it may have died out when its main prey animals went extinct. Humans probably had something to do with their extinction too.

Smilodon wasn’t the only big predator in North America during the ice age, though. It wasn’t even the only big feline predator. It shared its territory with the American lion and the American cheetah. Neither of those had saber teeth but they’re awesome so I’m going to tell you a little bit about them anyway.

The American lion died out at the same time as much of the other ice age megafauna, around 11,000 years ago. Unlike Smilodon, it’s closely related to modern big cats—in fact, most researchers consider it a subspecies of the modern African lion. We don’t know for sure if the males had manes, but we do know that the American lion was much bigger than modern lions although not as heavy as Smilodon. It probably stood almost four feet tall at the shoulder, or 1.2 meters. Remains of American lions have been found in the La Brea tar pits so we know they shared territory with Smilodon.

The American cheetah lived on the prairies of North America. Its body plan resembled the modern cheetah’s and it was built for speed, but researchers aren’t sure if it was actually closely related to the modern cheetah. It may be more closely related to the cougar. It was a little larger and heavier than a modern cheetah. Either way, it’s probably the reason why pronghorn antelopes are so fast. They can run over 55 miles per hour or 88 km per hour, much faster than gray wolves and cougars, their current predators. The American cheetah died out around 12,000 years ago.

There are a lot of saber-toothed cats known to science, all related to Smilodon. But there are other animals with similar teeth that are unrelated to the saber-toothed cats. Thylacosmilus atrox looked superficially like a saber-toothed cat. It lived in South America, with most fossils found in Argentina, and went extinct close to three million years ago, long before Smilodon appeared in South America. But Thylacosmilus wasn’t a feline at all. It wasn’t even slightly related to felines. In fact, it was a marsupial, sometimes called a pouched saber-tooth because marsupials keep their babies in pouches, like kangaroos and possums.

Thylacosmilus was about the same size as Megantereon or a modern jaguar. Its saber-like canines were bigger than Smilodon’s and had roots so deep they were practically pressed up against the braincase. But it had something no saber-toothed cat had. Its lower jaw had a pair of bony downward projections called flanges. Think of it as a chin that went horribly wrong. The chin bones pointed downward at the same angle that the fangs pointed downward, and apparently protected them. Researchers aren’t sure if the fangs were actually inside the mouth or just pressed up against the outside of the chin.

Like Smilodon and its relatives, Thylacosmilus had immensely powerful forelegs that it used to grapple prey. But its jaws were weak. Smilodon’s jaws were much weaker than a big cat’s, but Thylacosmilus literally couldn’t outbite a domestic cat. Researchers think it grappled and subdued its prey with its forelegs, then delivered a precision bite with its fangs that severed the animal’s windpipe or major neck arteries. To do this, it didn’t need a strong bite, it needed strong neck muscles, and that’s exactly what it had.

Kolponomos was another saber-toothed animal, totally unlike Smilodon except for its teeth and powerful neck muscles. It’s related to bears, but that branch of the bear family also gave rise to pinnipeds like seals. Kolponomos lived around 20 million years ago along the Pacific coast and used its fangs not to bite the necks of its prey, but to pry shellfish off of rocks. Its snout was narrow and sloped downward, but we don’t have a complete skeleton so we don’t know how big it was or what it really looked like, but it probably resembled a buff sea otter with big fangs more than a seal or bear.

Clearly, saber teeth have evolved multiple times in different types of animals to serve different purposes. They’re not a recent development, either. 250 million years ago, just before dinosaurs evolved and took over the world. An animal called a gorgonopsid, or gorgon for short, lived in what is now Africa and Eurasia. Not a whole lot was known about it until 1998 when a very nearly complete skeleton was discovered in South Africa.

Complete skeletons are almost never found in the fossil record. Dinosaur and other animal skeletons displayed in museums are usually assembled from different individual animals. Sometimes a particular bone has never been found at all so scientists have to make an educated guess. But this gorgon looked like it had died and just flopped over. Nothing ate parts of it, nothing scattered its bones after it decayed. There it was, just waiting for the paleo team to find it.

Gorgon wasn’t a mammal. It wasn’t exactly a reptile either. It was a precursor to mammals, a reptilian creature with mammalian characteristics. It resembled a lion crossed with a monitor lizard, although researchers aren’t sure if it had actual fur or both bristles and scales. It was big—some ten feet or 3 meters long with saber-tooth fangs nearly 5” or 12 centimeters long. Reptiles living today have legs that stick out from the sides of their bodies, so when they walk their bellies are very close to the ground, but gorgon’s stance was different. Its walk probably resembled what’s called the “high walk” of crocodilians, where the gator lifts its body and tail off the ground entirely to walk more easily and quickly on land. Researchers think gorgon hunted by ambushing its prey and delivering a massive bite, then retreating to wait for the injured animal to weaken. This is similar to how komodo dragons hunt.

Gorgon died off in the Permo-Triassic extinction event 250 million years ago. Everyone knows about the Cretaceous-Paleogene extinction that ended the rule of the dinosaurs, but the Permo-Triassic extinction was even worse. More than 95% of all marine animals died out, and some 70% of land animals. Even a lot of insects went extinct, and some evidence suggests that a lot of plants went extinct too. Scientists don’t know what caused the extinctions, but it might have been a meteor strike like the one generally accepted to have caused the Cretaceous-Paleogene event. Whatever happened, it hit marine life hard because the oceans became extremely acidic due to increased CO2 levels in the air and the increased temperature at the ocean’s surface in many areas—104o F or 40o C. It took millions of years for the oceans to recover.

So far all the animals in this episode are extinct. While a lot of living animals have fangs of one kind or another, there don’t seem to be any that use their fangs the way saber-toothed cats did. But I don’t want to leave you after saying, “Yeah, something happened and everything DIED,” so I’ll finish up by talking about the sabertooth fish, of the family Evermannellidae. It’s alive and it’s wonderfully creepy.

The sabertooth fish lives in the depths of tropical and subtropical waters. It has tubular eyes that point upwards so it can see its prey, mostly squid, silhouetted against the far-off surface. It’s grayish-brown in color with a greenish iridescence. Its fins are brown. It has smooth skin without scales and a big mouth that can open extremely wide, which is good because the sabertooth fish can swallow prey that’s actually bigger than it is. Its stomach distends to hold whatever can fit down its gullet. This sounds terrifying, especially when you look at its teeth, but keep in mind that it’s only about seven inches long, or 18 cm. It has two pairs of curved fangs, one in the upper jaw, one in the lower, with smaller teeth in the back of its mouth. If you’ve ever tried to catch a living squid with just your mouth—and I really hope you have not—you’ll probably have noticed that it’s hard to keep the squid from slithering away. Wouldn’t some saber teeth help with that? The sabertooth fish thinks so.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on iTunes or whatever platform you listen on. We also have a Patreon if you’d like to support us that way. Rewards include stickers and twice-monthly bonus episodes.

Thanks for listening!

 

Episode 033: Dunkleosteus, Helicoprion, and their weird-toothed friends

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This week we’ll learn about some terrifying extinct fish, the armored dunkleosteus and the spiral-toothed helicoprion, plus a few friends of theirs who could TEAR YOU UP.

Dunkleosteus did not even need teeth:

Helicoprion had teeth like crazy in a buzzsaw-like tooth whorl:

Helicoprion’s living relatives, chimaeras (or ghost sharks) are a lot less impressive than they sound:

Helicoprion probably looked something like this:

But helicoprion has been described in all sorts of wacky ways over the years:

So what are the odds this rendition of edestus is correct? hmm

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week we’ve got a listener suggestion! Will B. suggested placoderms, which were armored fish that lived hundreds of millions of years ago. He especially recommended Dunkleosteus. I looked it up and went, “Oh holy crap,” so you bet we’re going to learn about it today. I’m also pairing that terrifying fish with a really weird shark relation called Helicoprion. And we might even take a look at a few other fishes while we’re at it. Creepy extinct fish for everyone! Oh, and Will asked that I include more metric conversions. [heavy sigh] okay I guess

If you had happened to live around 350 million years ago when Dunkleosteus was alive, you would be a fish. Well, you would probably be a fish. I don’t know for sure. That was during the Late Devonian period, and the Devonian is remembered as the “age of fish” by undergraduate geology and palaeo students everywhere. While land plants were evolving like crazy, developing true roots and seeds, fish were even crazier. Ray-finned fish evolved during the Devonian and so did lobe-finned fish like coelacanths. The first amphibious critters developed in shallow lakes and started to spend time on land, and in the ocean there were early sharks, lots of trilobites, and a whole lot of armored fish. Including, eventually, dunkleosteus.

Dunkleosteus terrelli was the biggest species of placoderm. It probably grew over 30 feet long OR TEN METERS, WILL, which made it bigger than a great white shark. But dunkleosteus didn’t have teeth. And before you think, oh, it must have been a filter feeder or something, oh no. It didn’t need teeth. Instead it had bony plates like a gigantic beak. It could open and close its jaws incredibly fast—something like one 50th of a second—and could bite through armor and bone no problem. One article referred to its jaws as sheet-metal cutters. Scientists think its bite was as powerful as that of a T rex, although it didn’t quite match that of megalodon, but since T rex and megalodon both lived many millions of years later than Dunkleosteus, it’s useless to speculate who would win in a fight. But my money’s on Dunkleosteus.

Dunkleosteus wasn’t a fast swimmer. Its head was covered in heavy armor that probably served two main purposes. One, the armor plates gave its massive jaw muscles something substantial to attach to, and two, it kept its head safe from the bites of other placoderms. That’s right. Dunkleosteus was a cannibal.

We actually don’t know exactly how long Dunkleosteus was or what most of its body looked like. The only fossils we’ve found were of the head armor. We do have complete fossils and body impressions of other, much smaller placoderms, so since all placoderms seemed to have the same body plan we can make good guesses as to what Dunkleosteus looked like.

One surprising thing we do have associated with Dunkleosteus fossils are some remains of its meals. These are called fish boluses, and they’re basically just wads of partially-digested pieces of fish that either get horked up by whatever ate them or pass through the digestive tract without being fully digested. From the fish boluses, we know that Dunkleosteus probably preferred the soft parts of its prey and didn’t digest bones very well.

In 2013, a fossil fish over 400 million years old was described that combines features of a placoderm skeleton with the jaw structure that most bony fishes and four-footed animals share. Some other early bony fishes discovered recently also show some features of placoderm skeletons. What does that mean? Well, until these discoveries, researchers had thought bony fishes weren’t very closely related to placoderms. Now it looks like they were. And that means that placoderm jaws, those fearsome cutting machines, were actually the basis of our own jaws and those of most animals alive today. Only, in our case they’re no longer designed to shear through armor and bone. Maybe through Nutter Butters and ham sandwiches instead.

So what happened to dunkleosteus? Around 375 million years ago something happened in the oceans—not precisely an extinction event, but from our perspective it looks like one. Even without human help species do go extinct naturally every so often, and when that happens other species evolve to fill their ecological niches. But during the late Devonian, when species went extinct in the ocean… nothing took their place.

We don’t know what exactly was going on, but researchers have theories. One suggestion is that, since sea levels were rising, marine environments that were once separated by land got joined together. Species that had evolved in one area suddenly had access to a much bigger area. They acted like invasive species do today, driving native species to extinction and breeding prolifically. They kept new species from developing, and caused a breakdown in the biodiversity of their new territories. This only happened in the oceans, not on land, which adds credence to the theory.

It took a long, long time for the oceans to fully recover. For example, coral reefs disappeared from the fossil record for 100 million years as corals almost died out completely. But the animals that had already started evolving to take advantage of life on land survived and thrived—and that led to us, eventually. Us and our little unarmored jaws.

From Dunkleosteus and its sheet-metal cutter beak let’s go to another fish that looked like a shark but had teeth that are so bizarre I can’t even understand it. Helicoprion and its tooth whorl have baffled scientists for over a century.

The various species of Helicoprion lived around 290 million years ago. Like sharks, only its teeth are bony. The rest of its skeleton is made of cartilage, which doesn’t preserve very well.

So what’s a tooth whorl? It resembles a spiral shell, like a snail’s, only made of teeth. I’m not even making this up. Originally people actually thought they were some kind of weird spiky ammonite shell, in fact. Then someone pointed out that they were made of teeth, but no one could figure out what earthly use a circular saw would be if you were a fish and just wanted to eat other fish. Where would you even keep a circular saw of teeth?

Various suggestions included putting the tooth whorl at the very end of the lower jaw, just sort of stuck out there doing nothing; putting the tooth whorl way in the back of the throat where I guess it would cut up fish as they went down; on the snout, on the back, or even on the tail, which are not places where teeth typically do much good. Originally researchers thought the tooth whorl was probably a defensive trait, but now it’s accepted that it was used the way the rest of us use our teeth, which is to eat things with.

The smallest teeth in a tooth whorl are on the inside curls and the biggest are on the outside. Eventually researchers realized the small teeth were from when the individual was a baby fish and had little teeth. Like sharks, helicoprion kept growing teeth throughout its life. Unlike sharks, it didn’t lose its old teeth when the new ones grew in. The older, smaller teeth were just pushed forward along the curve of the whorl and eventually were buried within the animal’s jaw, with only the biggest, newest teeth actually being used.

In 1950 a crushed tooth whorl was found with some cranial cartilage, so scientists knew that the whorl was associated with the head and wasn’t, for instance, on the dorsal fin. That fossil was found in Idaho and consisted of 117 teeth. The whorl was 23 cm in diameter, or about 9 inches across, although slightly larger ones have been found. In 2011 the fossil was examined with a state-of-the-art CT scanner and a 3D computer model generated of the animal’s skull.

Researchers think they have a pretty good idea of what a living helicoprion’s head and jaws looked like. The tooth whorl was fused with and extended the full length of the lower jaw. It grew inside the mouth roughly where the tongue would be if it had a tongue, which it did not. Helicoprion didn’t have teeth in its upper jaw, so the tooth whorl acted less like chompers than like a meat slicing machine. When it closed its mouth, the tooth whorl was pushed back a little and would therefore slice through any soft-bodied prey in the mouth and also force its prey deeper into its mouth. Helicoprion probably ate small fish, cephalopods, and other soft-bodied organisms.

Since we don’t have any fossils or impressions of helicoprion’s body, we don’t know for sure what it looked like, but researchers estimate it probably grew to around 13 feet or 4 meters, but may have possibly exceeded 24 feet or 7.5 meters.

For a long time researchers thought helicoprion was a shark, but it’s now classified as a type of chimaera, which are small weird-looking shark-like fish known also as ghost sharks, spookfish, ratfish, and rabbit fish. I’m going to call them ghost sharks because that’s awesome. They’re not that closely related to sharks although they do have cartilaginous skeletons, and most species like the ocean depths. Ghost sharks have been spotted at depths of 8,500 feet, or 2,600 meters. The longest any species grows is around 5 feet, or 150 cm. Unlike helicoprion, they don’t have exciting teeth. They don’t really have teeth at all, just three pairs of tooth plates that grind together. Some species have a venomous spine in front of the dorsal fin.

While we’re talking about shark-like fish with weird teeth, let’s discuss Edestus, a genus of shark-like fish with weird teeth that lived around 300 million years ago, around the same time as dunkleosteus. It was related to helicoprion but it didn’t have a tooth whorl. Instead it had one curved bracket of teeth on the lower jaw and one on the upper jaw that meshed together like pinking shears. You know what pinking shears are even if you don’t recognize the name. Pinking shears are scissors that have a zigzag pattern instead of a straight edge, so you can cut a zigzag into cloth but not paper because do not dare use my pinking shears for anything but cloth. It dulls them.

Anyway, like helicoprion Edestus didn’t shed its teeth but it did grow new ones throughout its life, so like helicoprion it had a bunch of teeth it no longer needed. In Edestus’s case we don’t have any bits of skull or jaw cartilage to give us a clue as to how its teeth sat in its jaw. A lot of scientific art of Edestus shows a shark with a pointy mouth, where the upper point curves upward and the lower point curves downward with teeth sticking out from the middle. Sort of like an open zipper, if the zipper part was teeth and the non-zipper side was a shark’s mouth. To me that looks sort of ridiculous, and I suspect in reality Edestus looked a lot more like helicoprion. The downward and upward curved parts of the tooth arc was probably buried within its jaw, not sticking out. But that’s just a guess based on about 30 minutes of research.

Researchers estimate that the largest species of Edestus probably grew to about 20 feet long, or 6 meters. No one’s sure how or what it ate, but one suggestion is that if its teeth did project out of its mouth, it might have slashed at prey with its teeth sort of like a swordfish slashes prey with its elongated beak. Hopefully scientists will find a well preserved specimen one day that will give us some clues as to what Edestus looked like, at which point I bet the drawings we have now will look as silly as helicoprion with a tooth whorl perched on its nose.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on iTunes or whatever platform you listen on. We also have a Patreon if you’d like to support us that way. Rewards include stickers and twice-monthly bonus episodes.

Thanks for listening!

Episode 032: Some New Zealand birds

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This week’s episode is about several New Zealand birds, from the still-living kiwi to the mmmmmaybe extinct moa! Note: I’m going to start putting a full transcript of each episode in the show notes for those who would like to know what words I’m mispronouncing and for those who may have hearing issues. Transcripts will be below the pictures.

A kiwi:

Superman has fought everything.

The controversial blurry “moa” picture taken by Freaney. Probably not a moa.

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Before we get started, apologies for my voice. About the time I finally got over the cough I picked up at WorldCon in Finland, I went to DragonCon in Atlanta and got a big juicy cold. Hopefully I don’t sound too gross. My traveling for the year is over so I’m looking forward to having time to really dig into some fun topics for the podcast. In particular, I’m going to be covering some of the creepier strange animals in October, because Halloween is the best. And yes, Bigfoot is going to make an appearance.

This week’s episode is about some amazing birds from New Zealand. We learned about the takahe way back in episode seven, a big silly-looking flightless bird that was once thought extinct until its rediscovery in the middle of the last century. This week we’ll look at some other birds, some of them happily alive, some that are definitely extinct. At least, we’re pretty sure they are.

New Zealand wasn’t settled by humans until the late 13th century, only about 750 years ago. That’s mind-blowing until you take a look at a globe. New Zealand isn’t just a hop skip and jump away from Australia, it’s 900 miles away over open ocean. It’s 600 miles away from the Pacific Islands. That’s a long, long trip to make in a small boat, especially when you’re not sure if there’s any land out that way. But sometime between the years 1250 to 1300, people from eastern Polynesia discovered this new land. They liked it and stayed, and their descendants are now known as the Maori.

I know we’ve been talking about tectonic plates in a number of episodes recently. I haven’t done it on purpose—it’s just part of learning how and why different animals developed in different places. It’s definitely relevant when it comes to New Zealand.

New Zealand is just a little part of an otherwise submerged continent called Zealandia, or sometimes Tasmantis, which I actually prefer. Tasmantis. If Zealandia weren’t mostly under the ocean, it would be about half the size of Australia. Around 90 million years ago Zealandia, Australia, and Antarctica were all part of the supercontinent Gondwana. As Gondwana broke up, Zealandia separated from Antarctica and Australia around 80 million years ago, then slowly sank into the ocean.

After Zealandia separated from Gondwana, a cataclysmic event, probably a humongous meteor strike, led to the extinction of some 85% of the animals on earth. In most of the world, mammals began to evolve like crazy to fill the vacant ecological niches after the dinosaurs died off. But Zealandia didn’t have very many mammals to start with, and by 25 million years ago it was mostly underwater anyway except for the peaks of New Zealand, which were being pushed up slowly by tectonic forces—a process that’s still ongoing.

When travelers from Polynesia first landed on New Zealand, the only mammals on the islands were three species of bat. But there were birds in abundance, from enormous moas and eagles to tiny kiwi. Almost every ecological niche was filled by a bird.

Europeans first visited New Zealand in 1642. It didn’t go well and no one came back until 1769, and after that things got messy and lots of people died from war and introduced diseases. Around the mid-19th century Europeans started moving to New Zealand. Between them, the Maori, and introduced mammals like rats and dogs, a whole lot of birds went extinct.

I just want you to know that it took me hours and hours and hours to research all that stuff about Zealandia. Hopefully I got it right. I’m ready to talk about birds now.

Let’s start with a bird that is so unique to New Zealand that you’ll sometimes hear people call New Zealanders kiwis. There are five species of kiwi, all of them rare and protected. They’re round brown poofs of birds with long legs and long bills, and they eat worms, insects, seeds, fruit, frogs, and other things like that. They prefer to live in forests and usually mate for life, and can live for 50 years.

The kiwi has a lot of unusual characteristics. It’s flightless but has wings less than an inch long hidden under its feathers. Each wing has a tiny claw at its tip that doesn’t seem to have a use. The kiwi has no tail. Unlike every other bird out there, its nostrils are at the tip of its bill. The kiwi has a good sense of smell and may detect worms and other underground prey by smell, which should make you pause and wonder what earthworms smell like. The kiwi also has sensory pits at the tip of its bill that helps it detect vibrations, though, so it’s possible its good sense of smell is less important than researchers previously thought. When a kiwi detects its prey, it stabs its bill into the ground to catch it, which frequently leads to the kiwi later having to snort dirt out of its nostrils. Evolution does what it can, folks, but it’s not perfect.

Since it can’t fly and doesn’t need flight feathers, the kiwi’s feathers are hair-like and downy. But most curious of all is its egg. The kiwi is about the size of a chicken, but its egg is six times the size of a chicken egg and can weigh an entire pound. It’s so big that the female can’t even eat the last few days before she lays the egg. There’s no room in her body for food.

After the female lays her egg, the male incubates it. That huge egg has a huge yolk to feed the baby inside, so when the baby kiwi hatches, it’s ready to go. After a few days it leaves the nest and starts foraging, usually with its dad alongside for the first few weeks. It takes several years for it to grow to adult size.

The kiwi is territorial and will fight other kiwis that stray into its territory. Only its mate and its own offspring are allowed in its territory. It has powerful legs with claws that can inflict quite a bit of damage, and it can run faster than a human.

Scientists used to think the kiwi was closely related to moas, which we’ll talk about in a minute, but DNA studies have determined that its closest relative is the extinct elephant bird of Madagascar—and the elephant bird is the topic for a future episode.

The Maori describe a huge black swan called a Pouwa that lived in the Chatham Islands, but it had already gone extinct by the time Europeans arrived in the area in the late 1700s. Until recently researchers thought it was just the Australian black swan, either a population that lived in New Zealand or the occasional individual that flies across the Tasman Sea. Australian black swans were introduced to New Zealand in the 1860s.

But a recent study of DNA from fossilized swan remains from New Zealand show that it wasn’t the same bird as the Australian black swan but a related species. Around one or two million years ago Australian black swans lived in New Zealand and evolved into a separate species, heavier than the Australian birds with longer legs and shorter wings. It might have been a poor or reluctant flier and might have been on its way to evolving into flightlessness before it was eaten into extinction by the Maori.

The big name in extinct birds of New Zealand is the moa. Nine species of moa are recognized today, although in the past researchers thought there were a lot more. It turns out that female moas of some species were much larger than the males, so much so that scientists once thought they were looking at two different species. Moas were big flightless birds that in shape resembled big flightless birds from other parts of the world, known as ratites, which includes ostriches. Until DNA testing most researchers thought moas were closely related to the ratites of Australia, emus and cassowaries. But no, they are most closely related to a group of birds from Mexico, Central America, and South America collectively called tinamous. Tinamous are a type of ratite, but they can fly. They’re all fairly small and somewhat resemble quail and other game birds that spend a lot of time foraging on the ground.

Moas, however, are big. They are really big. Originally scientists mounted their skeletons so that the neck stuck more or less straight up, but now we know that they held their necks more like ostriches, with a gentle S-shaped curve. Even so, females of the biggest species, the South Island Giant Moa, stood around six and a half feet high at the back. That doesn’t even count the neck. With the neck outstretched, a big female moa could probably reach leaves twelve feet off the ground.

All moas were plant-eaters. Some ate leaves and fruit, others were adapted to digest tougher plant material like twigs, moss, and bark. Unlike other flightless birds, they didn’t have wings at all, not even for display, not even vestigial wings. They just flat-out didn’t have forelimbs. They did have strong legs although they probably couldn’t run very fast, unlike other flightless birds like ostriches. After all, moas didn’t need to run to escape predators. They only had one predator, and that was one they couldn’t outrun: Haast’s eagle.

Haast’s was the biggest eagle that ever lived, although its wings were comparatively short—only around 10 feet wide for big females, closer to 8 ½ feet wide for big males and more average-sized females. Since much of its hunting range was forested, its shorter wings probably helped it maneuver. It had a long tail too. But it had enormous talons with claws over four inches long, and its bill was similarly big. In fact, its talons were so big that its scientific name, Harpagornis moorei, means Moore’s grappling hook bird.

The Haast’s eagle’s prey was the moa, and when moas went extinct after overhunting, the Haast’s eagle went extinct soon after since it just didn’t have anything to eat. It did apparently try to adapt its hunting habits, though. Maori legends tell of the Pouakai, an enormous bird that would sometimes kill humans.

It’s pretty certain that Haast’s eagle is extinct. If it was still around, ranchers would spot it picking off sheep and calves. But the moa is something else. Moa sightings pop up pretty frequently in remote areas of New Zealand.

One of the smallest species of moa, Megalapteryx, also called the upland moa, may have survived on the south island until the mid-19th century. The upland moa was three or four feet tall including the head and neck, and was completely covered with feathers except for its bill and feet, since it lived in the mountainous areas of New Zealand’s south island where the climate was cool. It laid one or two blue-green eggs a year and the male took care of the babies.

Its accepted date of extinction is around the year 1500, but there have been numerous sightings since then. In 1880, Alice McKenzie, who was then seven years old, saw a three-foot-tall bird with blue feathers, dark green scaled legs, and three claws on each foot. She ran to get her father, but when they returned the bird had gone, although it had left big tracks in the sandy soil. She saw the same bird again in 1889.

The problem with this sighting is that the upland moa had feathered legs, and as far as we know no moas had blue plumage. We have plenty of upland moa feathers, which are grey, black and white. We even have mummified upland moa remains. Not only did Alice describe her bird as blue, she specifically noted it was the blue of a pukeko, which has vibrant plumage that varies from navy blue to violet. This wasn’t a grayish-blue bird. Alice herself thought, later in life, that she might have seen a takahe, which is also blue, but after the takahe was rediscovered she went to view some and was disappointed. They have red legs and she knew her bird’s legs were green.

But that’s not the only sighting. In addition to the sporadic accounts of big birds seen in the distance, in 1993 three men hiking in the Craigieburn Range saw what they described as a red-brown and gray moa some six feet high, including its neck. It ran off when it saw them, but one of the men, Paddy Freaney, ran after it and managed to get a photograph. He also got a few pictures of its footprints where it had stepped in a stream and then on a rock.

The picture is frustrating, to say the least. It’s so out of focus that it could be anything. However, I agree with one of the experts who have examined the photo, palaeoecologist Richard Holdaway, who says the figure’s neck is too thick for a moa. He thinks the picture is probably of a red deer. As far as I can find, Freaney’s photos of the footprints haven’t been released.

In 2007, a pair of cryptozoologists searching for moas in the hill country of the North Island spotted 35 footprints and what appeared to be a nest that they claimed were made by a group of moas, possibly a lesser moa. But considering that the pair of cryptozoologists are Rex and Heather Gilroy, who are notorious for being secretive, vague in their claims of evidence, and somewhat paranoid about their findings, I don’t expect them to show up with a live moa anytime soon. No other moa sightings or even rumors of moas living in the area have ever been uncovered.

It’s easy to dismiss this account, and the others, as wishful thinking, misidentification, and in some cases maybe outright hoaxes. Australian emus are raised in some areas of New Zealand and sometimes escape from captivity, too, which confuses the issue, since emus are big flightless birds that could easily be mistaken for moas at a distance. But there is something that makes me hopeful that the moa might still be around, especially one of the smaller species.

New Zealand’s south island is much less populated than its north island. Alice McKenzie’s sighting in 1880 was on her family’s farm near Milford Sound, which is now part of Fiordland National Park. This is a big nature reserve in the southwest corner of the south island, with rugged terrain and very few tracks passable to even offroad vehicles. The park includes the Murchison Mountains, which is where the takahe was rediscovered in 1948 after being thought extinct. So it’s entirely possible that a small species of moa might be hiding in the area. Maybe one day someone will get a really good picture—or better yet, a hiker or park ranger might come across a newly dead moa carcass and can bring it back for study.

We do have some subfossil moa remains that aren’t just skeletons and feathers. Dessicated body parts turn up occasionally, which has helped with DNA testing and our knowledge of what the living birds looked like. The moa is a good candidate for de-extinction by genetic cloning, and it would be really neat to have moas for sure running around in New Zealand again, so scientists can get right on that as far as I’m concerned.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on iTunes or whatever platform you listen on. We also have a Pattreon if you’d like to support us that way. Rewards include stickers and twice-monthly bonus episodes.

Thanks for listening!

Episode 031: Venomous Mammals

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This week we’ll learn all about venomous mammals: what are they, will they kill you, and why aren’t humans venomous because that would be cool. While you’re pondering your lack of venom, hop on over and enter my Goodreads giveaway for my new book Skytown! (Canada and U.S. only, sorry.)

The adorable and venomous water shrew:

The adorable and venomous European mole!

The adorable and venomous Hispaniolan solenodon (there is a pattern in this episode)!

The adorable and venomous Cuban solenodon!

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

For this week’s episode, we’re going to learn about venomous mammals. But first, an ad! Okay, not a real ad. If I ever do run advertisements on the podcast, I’ll put them at the very end so you don’t have to listen if you don’t want to. But I do want to tell you about my new book! It’s called Skytown and it’s published by Fox Spirit Books, a small British publisher you should totally support. All their books are good. Skytown is a fantasy adventure about two ladies who are airship pirates. The book isn’t intended for kids, but I estimate it at about a PG-13 rating—it has some bad language and some mild adult behavior and violence, but nothing adults only.

Right now I’ve got a Goodreads giveaway going on through the end of September 2017 for a paperback copy of Skytown, although in this case entries are limited to people in the United States or Canada. I’ll put a link to the giveaway page in the show notes in case you’re interested in entering, or if you just want to learn more about the book. It doesn’t have a whole lot to do with strange animals, although there are a few that are important to the plot, but I think it’s a lot of fun.

But now, back to the venomous mammals, and I get to work in a sneaky shout-out to the awesome podcast Varmints! In a recent episode about frogs, one of the hosts gives a good way to remember the difference between venomous and poisonous. If an animal bites you and you die, it’s venomous. If you bite an animal and then you die, the animal is poisonous. There are lots of venomous insects, lots of venomous reptiles, lots of venomous fish, lots of venomous amphibians, but not very many venomous mammals. Oh, and no venomous birds, but more about that later.

We’re most used to venomous snakes that inject poison with their fangs, but there are lots of ways to get venom into potential prey or a potential predator. Scorpions and bees inject venom with a stinger, for instance. Stingrays have barbed stingers on their tails, while some fish such as scorpionfish and dogfish sharks have sharp spines that are coated with toxins. Other fish, like stonefish, have spines that actually inject venom. Some lizards, including gila monsters and komodo dragons, have modified salivary glands in the lower jaw that contain venom, which is leached into a bite through the lower teeth, not through specialized fangs. Some types of amphibians, like the sharp-ribbed newt, actually puncture their own sides with their ribs when threatened, secreting toxins at the same time that coat the points of the ribs. And while poison dart frogs don’t inject venom, just secrete it and dare other animals to lick them, a few species of frog have little spines on the skull that injects venom when the frog headbutts an animal.

Most venom is a toxin that either renders prey helpless or kills it outright, or produces pain or adverse physical symptoms in predators. So it’s controversial to suggest that the anticoagulant found in vampire bat saliva is actually a venom. Likewise, the slow loris secretes a strong-smelling substance when threatened that can cause allergic reactions in some individuals but which isn’t technically a toxin.

Several species of shrew are definitely venomous, including the Eurasian water shrew. Water shrews are neat little animals even without venom. They’re around 4 inches long with a tail some 3 inches long. Like other shrews, its teeth have red tips due to iron concentrated in the enamel, which helps strengthen the tooth and keep it from wearing down as fast. The water shrew can only stay underwater about 20 seconds before needing to surface, but its fur traps air so water can’t get down to its skin. It also makes it look silvery if you get a picture of it as it’s diving. It lives in burrows near water and mostly eats aquatic organisms like fish, insects, snails, and amphibians. It mostly uses its sensitive whiskers to find prey.

And yes, it’s venomous. While its jaws aren’t strong enough to injure humans and other large mammals, it does a great job against small animals. The venom is present in its saliva, so when a shrew bites its prey, saliva naturally gets into the wound.

The European mole has venomous saliva too. Mostly it uses its venom to paralyze earthworms, which it eats, but it also sometimes eats shrews. Irony! Moles are around 4 to 6 inches long with strong forelegs with long claws that it uses to dig its burrows. Moles do have eyes and can see, but their eyes are tiny and protected by fur that grows over them. Its ears are similarly tiny and protected. The mole constructs elaborate tunnel systems and spends most of its life underground. It’s a solitary animal but like the old lady who lives up the hill from me, it always seems to know what its neighbors are up to. If a mole dies or is captured and removed from its burrow, its neighbors promptly move in on its territory. Earthworms are its favorite food but it will also eat insects.

The male platypus has a spur on the ankles of its hind feet that can inject venom. While venom is present through the year, its production is increased during the breeding season. Some researchers believe the venom is used when males fight each other. But the venom is incredibly toxic. It can kill animals as big as dogs outright, and while it won’t kill a human, it can certainly make the human wish they were dead. Not only is the pain excruciating and lasts for weeks, it can cause a heightened sensitivity to all pain for months. That seems a little like overkill. One good thing, though, is that recent research has isolated a form of insulin in the platypus’s venom that normally degrades very quickly, but that is much longer-lasting in the venom. Scientists are hopeful that learning more about it can lead to new treatment of diabetes in humans.

I swear I’m still planning an episode about platypuses pretty soon. They and their close cousins, echidnas, are freaky-deaky animals. So let’s skate right by the platypus for now and go on to discuss another freaky-deaky animal that you may not have heard of, the solenodon.

There are two species of solenodon, the Cuban and the Hispaniolan. They look a bit like small possums or big shrews, with long noses and long tails without fur. They climb well, although they can’t jump, and have relatively long legs, and they basically walk on their tiptoes. They can also be surprisingly clumsy, sometimes tripping themselves and tumbling to the ground. I thought I was the only one who did that. The Hispanolian solenodon is pale reddish-brown and gray while the Cuban solenodon is brown with a yellow-white face or head. Both are about a foot long not counting their eight-inch tails, and both have glands that secrete a musky smell.

The solenodon is one of those animals people like to call a living fossil. It’s been around since well before the dinosaurs went extinct, some 76 million years ago, and retains a number of characteristics considered primitive. There used to be a species in North America, but it went extinct sometime in the last two million years.

Females give birth to one or two babies at a time. Occasionally a litter of three is born, but the mother only has two teats, located toward the back of her belly and elongated so the babies can travel with her while they continue to nurse. That means a third baby doesn’t get much to eat.

The solenodon mostly eats insects and earthworms, but they’ll snack on just about anything, including carrion, fruit, and small animals. Two of the lower incisors have grooves, and when a solenodon bites, it injects venom into its prey through the grooves from modified salivary glands. The venom isn’t strong enough to kill a human, but it is painful. One solenodon kept in captivity in London bit a chicken, then ate it. Even though the chicken was bigger than he was.

The solenodon is shy and nocturnal. Its eyesight isn’t very good, but that’s okay, because it uses a form of echolocation to navigate and find prey. As it walks, it generates quiet clicking sounds the same way bats squeak, and it can interpret the echoes of its sounds to know what’s around it. It has good hearing and a very good sense of smell. Its long nose is extremely flexible—in fact, the Hispaniolan solenodon has a joint at the base of its snout to make it even more flexible. Since a lot of its prey hides in tree bark or crevices in the ground, it needs an extra investigative snoot.

You wouldn’t think such a little animal that mostly eats insects would be a big deal in the animal world, but until Europeans showed up on the island of Hispanolia, the Hispaniolan solenodon was pretty much a bigwig. Nothing ate it except the occasional eagle, so when Europeans showed up with dogs, cats, rats, and mongooses, the solenodon had no idea how to defend itself. While dogs bitten by solenodons do sometimes die, cats and rats eat a lot of the same prey the solenodon does and can outcompete it. The mongoose just eats the solenodon. The Cuban solenodon was similarly threatened by deforestation and introduced species. By 1970 researchers believed the solenodon was extinct. Fortunately, they were wrong, although both species are still rare. There used to be a population of the Hispaniolan solenodon in Haiti, but those do appear to be gone since there are few forested areas left for them to live in.

So why do a few mammals have venom while most of us don’t? Some researchers think venom used to be really common in mammals when dinosaurs were still alive. It was a useful defense when almost everything was bigger than mammals. But after most dinosaurs went extinct, and mammals began to evolve to fit new ecological niches, venom wasn’t as useful. Most mammal lineages lost the venom. Then again, we don’t know for sure if this is the case. Some other researchers think venom was never that common in mammals to start with. It’s hard to tell if an animal was venomous from fossil remains.

I mentioned earlier that no known venomous birds exist, but there are a few birds that make use of toxins from plants or insects they eat. For instance, the African spur-winged goose eats a lot of blister beetles, and blister beetles are toxic. If you touch one, it will secrete the toxin that’s powerful enough to raise blisters on your skin. Blister beetles are attracted to blooming alfalfa plants, which can cause a lot of problems for horses if any of the beetles are collected when the plants are dried and baled for hay. A couple of dead blister beetles in a single feeding of hay can kill the horse that eats them. But the spur-winged goose is immune to the beetle’s toxin. It collects the toxin in its tissues, which makes it poisonous. People have actually died as a result of eating its meat. Oh, and the goose has spurs on its wings—thus its name—that it uses to defend its territory from other birds. But the spurs aren’t venomous, although that would be really metal.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on iTunes or whatever platform you listen on. We also have a Patreon if you’d like to support us that way. Rewards include stickers and twice-monthly bonus episodes.

Thanks for listening!