Monthly Archives: April 2024

Episode 378: Ichthyotitan

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Thanks to Nathan-Andrew for suggesting giant ichthyosaurs!

Further reading:

Paleontologists unearth what may be the largest known marine reptile

Ruby and some other scientists with the ichthyotitan fossils [photos taken from this page]:

How the pieces fit together:

Show transcript:

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

This week we’re going to learn about some of the biggest animals that have ever swum through the oceans of this planet we call Earth, a suggestion from Nathan-Andrew.

We talked about ichthyosaurs way back in episode 63, but we haven’t really discussed these giant marine reptiles since. Ichthyosaurs and their close relations were incredibly successful, first appearing in the fossil record around 250 million years ago and last appearing around 90 million years ago. Most ichthyosaurs grew around 6 and a half to 11 feet long, or 2 to 3.3 meters, depending on species, so while they were pretty big animals, most of them weren’t enormous. They would have been fast, though, and looked a lot like fish or dolphins.

Even though ichthyosaurs were reptiles, they were warm-blooded, meaning they could regulate their body temperature internally without relying on outside sources of heat. They breathed air and gave birth to live babies the way dolphins and their relations do. They had front flippers and rear flippers along with a tail that resembled a shark’s except that the lower lobe was larger than the upper lobe. Some species had a dorsal fin too. They had huge eyes, which researchers think indicated they dived for prey. Not only were their eyes huge, they were protected by a bony eye ring that would help the eyes retain their shape even under deep-sea pressures.

We know a lot about what ichthyosaurs ate, both from coprolites, or fossilized poops, and from the fossilized remains of partially digested food preserved in the stomach area. Most ichthyosaurs ate cephalopods like squid and ammonites, along with fish, turtles, and pretty much any other animals they could catch. Ichthyosaurs also ate smaller ichthyosaurs.

Nathan-Andrew specifically suggested we look at Shastasaurus and Shonisaurus, two closely related genera that belong to the ichthyosaur family Shastasauridae. Both genera contained species that were much larger than the average dolphin-sized ichthyosaur. The biggest species known until recently was Shonisaurus sikanniensis, which grew to almost 70 feet long, or 21 meters.

Scientists are divided as to whether S. sikanniensis should be considered a species of Shonisaurus or if it should be placed in the genus Shastasaurus. The main difference is that species in the genus Shastasaurus were more slender and had a longer, pointier rostrum than species in the genus Shonisaurus. Either way, S. sikanniensis was described in 2004 and at the time was the largest ichthyosaur species ever discovered.

But in May of 2016 a fossil enthusiast came across five pieces of what he suspected was an ichthyosaur bone along the coast of Somerset, England. He sent pictures to a couple of marine reptile experts, who verified that it was indeed part of an ichthyosaur’s lower jawbone, called a surangular. Studies of the fossil pieces compared it to S. sikanniensis, and it was similar enough that the new fossil was tentatively placed in the family Shastasauridae. Based on those comparisons, scientists estimated that this new ichthyosaur might have grown to around 72 feet long, or 22 meters, or even longer.

Almost exactly four years after the 2016 discovery, in May of 2020, an 11-year-old named Ruby Reynolds was looking for fossils with her father on the beach at Somerset. She discovered two big chunks of a fossil bone that she thought might be important. Ruby’s father contacted a local paleontologist, who in turn reached out to the man who had found and helped study the 2016 surangular bone. They studied the 2020 fossil and determined that it too was a surangular bone, and looked a lot like the one found in 2016. Not only was it better preserved and more complete, it was bigger.

Ruby and her father joined the team of paleontologists searching for more pieces of the surangular, and they actually found them. The pieces fit together like jigsaw puzzle pieces.

The bone has been dated as being about 202 million years old, from right before the end-Triassic extinction event and 13 million years after the other most recent ichthyosaur fossils from this era. It was described in early 2024 and named Ichthyotitan, and I’m happy to report that Ruby and her father helped with the research and are both included in the list of authors in the paper describing it. They also helped name it.

The estimated size of this specific Ichthyotitan specimen is about 25 meters, or 82 feet. That’s incredibly huge, rivaling the biggest whales alive today. But one other detail about this ichthyotitan bone is even more stunning. When the animal died, it was still growing. It hadn’t reached its full size yet.

As a comparison, the biggest animal ever known to have lived is the blue whale. A blue whale can grow up to 98 feet long, or 30 meters. Until now, scientists thought that no other animal had ever reached the size of a blue whale. Now, some paleontologists suspect that a full-grown ichthyotitan might have been at least as long or even longer than a blue whale.

The next step, of course, is to find more of the fossils. Ichthyotitan’s only fossils so far have been found in Somerset, England, but fossils of closely related ichthyosaurs have been found in parts of California, Nevada, British Columbia, China, Italy, Switzerland, and Tibet. In other words, they might be found just about anywhere with rocks dating to about 200 million years ago. The next time you’re out for a walk, keep a look-out just in case you spot a bone belonging to the biggest animal that ever lived.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 377: The Giant-est Snake Ever

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Thanks to Max for suggesting Titanoboa!

Further reading:

Largest known madtsoiid snake from warm Eocene period of India suggests intercontinental Gondwana dispersal

This Nearly 50-Foot Snake Was One of the Largest to Slither on Earth

Meet Vasuki indicus, the ‘crocodile’ that was a 50ft snake

Titanoboa had really big bones compared to its modern relatives:

Vasuki had big bones too:

Show transcript:

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

Almost exactly two years ago now, Max emailed to suggest we talk about titanoboa. The problem was that we had covered titanoboa in episode 197, and even though there’s always something new to learn about an animal, in this case since titanoboa is extinct there wasn’t much more I could share until new studies were published about it. But as the years passed I felt worse and worse that Max was waiting so long. A lot of listeners have to wait a long time for their suggested episode, and I always feel bad. But still there were no new studies about titanoboa!

Why am I telling you all this? Because we’re finally going to talk about titanoboa today, even though by now Max is probably old and gray with great-grandkids. But we’re only going to talk about titanoboa to compare it to another extinct snake. That’s right. Paleontologists have discovered fossils of a snake that was even longer than titanoboa!

Let’s start with Titanoboa, because it’s now been a really long time since episode 197 and all I remember about it is that it’s extinct and was way bigger than any snake alive today. Its discovery is such a good story that I’m going to include it too.

In 1994, a geologist named Henry Garcia found an unusual-looking fossil in Colombia in South America, in an area that had been strip-mined for coal. Fifty-eight million years ago the region was a hot, swampy, tropical forest along the edge of a shallow sea.

Garcia thought he’d found a piece of fossilized tree. The coal company in charge of the mine displayed it in their office along with other fossils. There it sat until 2003, when palaeontologists arranged an expedition to the mine to look for fossil plants. A researcher named Scott Wing was invited to join the team, and while he was there he poked around among the fossils displayed by the mining company. The second he saw the so-called petrified branch he knew it wasn’t a plant. He sent photos to a colleague who said it looked like the jawbone of a land animal, probably something new to science.

In 2007, the fossil was sent for study, labeled as a crocodile bone. But the palaeontologists who examined the fossil in person immediately realized it wasn’t from a crocodile. It was a snake vertebra—but so enormous that they couldn’t believe their eyes. They immediately arranged an expedition to look for more of them, and they found them!

Palaeontologists have found fossilized remains from around 30 individual snakes, including young ones. The adult size is estimated to be 42 feet, or 13 meters. The largest living snakes are anacondas and reticulated pythons, with no verified measurements longer than about 23 feet long, or 7 meters. Titanoboa was probably twice that length.

Because titanoboa was so bulky and heavy, it would be more comfortable in the water where it could stay cool and have its weight supported. It lived in an area where the land was swampy with lots of huge rivers. Those rivers were full of gigantic fish and other animals, including a type of lungfish that grew nearly ten feet long, or 3 meters. Studies of titanoboa’s skull and teeth indicate that it probably mostly ate fish.

So if titanoboa was so huge that until literally a few days ago as this episode goes live, we thought it was the biggest snake that had ever existed, how big was this newly discovered snake? It’s called Vasuki indicus and while it wasn’t that much bigger than titanoboa, estimates so far suggest it could grow almost 50 feet long, or over 15 meters. It’s named after a giant serpent king called Vasuki from Hindu folklore, who symbolizes strength and prosperity.

Vasuki indicus was discovered in a mine in India in 2005. The original discovery consisted of 27 vertebrae, including some that were still articulated. That means they remained in place after the rest of the body decayed and were preserved that way, which helps palaeontologists better estimate the snake’s true size.

Like titanoboa, the fossils were misidentified at first. They were labeled as a known giant crocodile and set aside in the discoverer’s lab for decades. In 2022, paleontologist Debajit Datta joined the lab, and one of the things he wanted to study were these giant crocodile fossils. He started preparing them for study by removing the rock matrix from around them, and almost immediately realized they belonged to a snake, not a crocodile.

The fossils have been dated to about 47 million years ago in what is now India, in Asia. Titanoboa lived about 58 million years ago in what is now Colombia, in South America. The two snakes are related, although not closely, and this helps scientists determine how snakes spread across the world as the continents moved into their current positions.

Both snakes lived in what were then very similar habitats, a tropical, swampy area near the coast. The researchers think Vasuki spent most of its time on land, unlike titanoboa. It wasn’t as bulky as titanoboa and could probably maneuver on land a lot more easily.

Until titanoboa was described in 2009, a snake called Gigantophis was thought to be the largest snake that ever lived. It lived around 40 million years ago in what is now the northern Sahara desert and could grow over 35 feet long, or almost 11 meters. It turns out that Vasuki was closely related to gigantophis.

As it stands now, until more fossils are found and more studies are conducted and published, Vasuki is estimated to be slightly longer than titanoboa at maximum, making it the longest snake known, but titanoboa is still estimated to be the heaviest snake known. So they both win the largest snake award, but the real winner is us.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 376: The Horned Lizard AKA Horny Toad

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Thanks to Khalil for suggesting the horny toad, also called the horned lizard or horned toad!

Further reading:

The Case of the Lost Lizard

The Texas horned lizard:

Texas Horned Lizard (Phrynosoma cornutum)

The rock horned lizard [photo taken from article linked above]:

Show transcript:

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

This week we’re going to learn about a reptile suggested by Khalil, who is Leo’s friend, so a big shout-out to both. Khalil wants to learn about the horny toad, also called the horned toad or horned lizard.

We talked about it briefly back in episode 299. The horny toad is actually a lizard that lives in various parts of North America, especially western North America, from Canada down through much of the United States and into Mexico. The largest species is the Texas horned lizard, with a big female growing about 5 inches long, or almost 13 cm, not counting its tail.

The horny toad does actually resemble a toad in some ways. Its body is broad and rounded and its face has a blunt, froglike snout. Its tail is quite short. It’s also kind of sluggish and spends a lot of time just sitting in the sun, relying on its mottled coloration to camouflage it. If it feels threatened, it will actually just freeze and hope the predator doesn’t notice it. It’s covered with little pointy scales, and if a predator does approach, it will puff up its body so that the scales stick out even more and it looks larger. It also has true horns on its head, little spikes that are formed by projections of its skull, and if a predator tries to bite it, the horny toad will jerk its head up to stab its horns into the predator’s mouth.

Horny toads mainly eat a type of red ant called the harvester ant. The harvester ant is venomous but the horny toad is resistant to the venom and is specialized to eat lots and lots of the ants. Its esophagus produces lots of mucus when it’s eating, which collects around the ants and stops them from being able to bite before they die.

Because it eats so many venomous ants, many scientists think the horny toad stores some of the toxins in its body, especially in its blood. Its blood tastes especially bad to canids like coyotes that are common in the areas where it lives. But it does the horny toad no good to have bad-tasting blood if a predator has to bite it to find out, so the horny toad has a way to give a predator a sample of its blood in the weirdest way you can imagine.

If a horny toad is cornered by a predator and can’t run away, and puffing up isn’t helping deter the predator, the lizard has one last trick up its sleeve. It increases the blood pressure in its head by restricting some of the blood vessels carrying blood back to the heart, and when the blood pressure increases enough, it causes tiny blood vessels around the eyelids to rupture. It doesn’t just release blood, it squirts blood up to five feet away, or 1.5 meters. As if that wasn’t metal enough, the horny toad can aim this stream of blood, and it aims it right at the predator’s eyes.

Imagine for a moment that you are a hungry coyote. You’re young and don’t know that horny toads taste bad, you just know you’ve found this plump-looking lizard that doesn’t move very fast. It keeps puffing up and looking spiky, but you’re hungry so you keep charging in to try and grab it with your teeth in a way that won’t hurt your tongue on those spikes. Then, suddenly, your eyes are full of lizard blood that stings and makes it hard to see, and the blood drips down into your mouth and it tastes TERRIBLE. It doesn’t matter how hungry you are, this fat little lizard is definitely off the menu. Meanwhile, the horny toad is fine.

Scientists aren’t sure if every species of horny toad can squirt blood. Some species probably can’t, while some do it very seldom. It also doesn’t help against some predators, like birds, who don’t have a great sense of taste and aren’t affected by the toxins in the horny toad’s blood.

The horny toad relies on the harvester ant for most of its specialized diet, although it does eat other insects too. It can’t survive without eating harvester ants. The problem is, the harvester ant is in decline after fire ants were introduced to North America from South America. The horny toad doesn’t eat fire ants, and the fire ants out-compete the local harvester ants, leaving the horny toad with less and less food.

Humans really don’t like fire ants, which can cause damage to homes when they dig their huge underground nests, and which inflict really painful bites. When people try to get rid of fire ants, sometimes the treatments also kill harvester ants. Incidentally, some animals that really love to eat fire ants include armadillos, black widow spiders, wolf spiders, and bobwhites.

The Texas horned lizard lives throughout a fairly large range, so although its numbers are in decline along with its ant food, it’s still doing okay for now. But not every horny toad is so lucky.

The rock horned lizard, also called Ditmars’ horned lizard, is only found in one small part of Sonora in northern Mexico. It was first discovered by science in 1891, when an archaeological expedition caught one. The lizard was described in 1906 but by then it hadn’t actually been seen in the wild since 1897, when two more were caught by a man who donated them to the New York Zoological Park. Those were the only three specimens that had ever been collected. Herpetologists worried that the rock horned lizard had gone extinct.

The main issue was that no one was exactly sure where those three specimens had been collected and no one knew exactly where the 1891 expedition had traveled. The man who caught the two lizards in 1897 didn’t say exactly where he’d caught them, just that it was in northern Sonora. But what a scientist named Vincent Roth realized when researching the lizard is that the three preserved specimens probably still contained undigested and partially digested food in their bodies, and that if the insects the lizards had eaten could be identified, it could give an important clue as to where the lizards had lived.

Dr. Roth requested that the gut contents be removed from the 1891 specimen for study, and also from one of the 1897 specimens. The third specimen had been taxidermied and the guts discarded. Dr. Roth cleaned the gut contents with alcohol and examined them microscopically, and found the remains of 14 insects, the seeds of three different species of grass, and some pebbles. All this happened in 1970, so instead of emailing a bunch of experts for help, Dr. Roth had to write physical letters to specialists throughout the world for help identifying the insects.

The specialists were happy to help, and they determined that the pebbles and grass seeds would have been eaten by accident when the lizard slurped up ants carrying them. The lizards had the remains of several different ants in their digestive tracts, including harvester ants, along with weevils, jumping spiders, grasshoppers, and other insects. These were identified, including some rare ones only ever found in certain areas of Sonora. Even the grass seeds and the pebbles were identified.

It all pointed to a particular mountain range in northern Sonora, and an expedition was arranged by Dr. Roth to search for the lizard. But they didn’t find it! They made plans to return, but asked the local people to keep an eye out for a specific type of horned lizard. In 1971 a report came of a rock horned lizard discovered by a local, followed soon by a few others. The lizard was safe, although it’s rare. Scientists had just been looking in the wrong place for it.

Since the rock horned lizard is only a few inches long and blends in so well with its surroundings, it’s no wonder it was hard to find. Fortunately it’s been rediscovered so that scientists can study it and keep it safe. The next step is to keep the harvester ants safe so that all the horny toads have plenty of yummy ants to eat.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 375: The Praying Mantis Re-Revisited

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Thanks to Elijah and an anonymous listener for suggesting that we talk about some more species of praying mantis!

Further reading:

The luring mantid: Protrusible pheromone glands in Stenophylla lobivertex (Mantodea: Acanthopidae)

Dragons and unicorns (mantises) spotted in Atlantic forest

Citizen scientists help discover new mantis species

The dragon mantis [photo from first article linked above]:

The possibly new species of unicorn mantis [picture from second article linked above]:

Inimia nat, or I. nat, discovered after a citizen scientist posted its photo to iNat [photo from third article linked above]:

Show transcript:

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

This week we’re going to revisit a popular topic that we’ve covered before, especially in episode 187, but which has been suggested by a couple of listeners who want to know more. It’s the praying mantis. Thanks to Elijah and an anonymous listener who suggested it. Elijah even keeps mantises as pets and sent me some pictures of them, which was awesome.

The praying mantis gets its name because it holds its spiny front legs forward and together, which sort of resembles someone holding their hands together while praying. That’s the type of praying spelled p r a y ing, not p r e y ing, which refers to killing and eating other organisms, but the praying mantis does that too. It’s a predator that will eat anything it can catch, including birds, fish, mice, lizards, frogs, and of course lots of insects.

There are thousands of mantises, also called mantids, with most species preferring tropical and subtropical climates. In general, a mantis has a triangular head with large eyes, an elongated body, and enlarged front legs that it uses to catch prey. Most species have wings and can fly, some don’t. Most are ambush predators.

We talked about several species of mantis in episode 187, and some more in episode 201. You can go back to those episodes to find out general information about mantises, such as how their eyes work and whether they have ears and whether they actually eat their mates (they do, sometimes). This week we’re going to focus on some findings about mantises that are new since those episodes came out.

The dragon mantis, Stenophylla lobivertex, was only discovered in the year 2000. Its body is covered with gray-green or green-brown lobes that help it blend in with the leaves in its forest home, but that also kind of make it look like a tiny dragon covered with scaly armor. Even its eyes are spiky. It lives in the tropics of South and Central America where it’s quite rare, and it usually only grows about an inch and a half long, or 4 cm. It spends most of the time in treetops, where it hunts insects, spiders, and other small animals.

Unlike many mantis species, the dragon mantis is mostly nocturnal. That’s one of the reasons why we don’t know a lot about it. In late 2017 through mid-2018, one member of a team of scientists studying animals in Peru noticed something weird in a captive female dragon mantis. Frank Glaw isn’t an expert in insects but in reptiles and amphibians, but he happened to observe what looked like two tiny maggots emerge from the mantis’s back, roughly above her last pair of legs, but then disappear again into her back. He thought he was seeing the results of parasitism, but a mantis expert suspected it was something very different.

Some praying mantis females release pheromones from a gland in about the same place on the back. Pheromones are chemicals that can be sensed by other insects, usually ones in the same species. They’re most often used to attract a mate. It turns out that the female dragon mantis has a Y-shaped organ that’s up to 6 mm long that can release pheromones in a particular direction. The mantis can even move the prongs of the Y around if she wants to. Because she only does this at night when she’s sure she’s safe, and only when she hasn’t found a mate yet, and because this species of mantis is really rare, no one knew that any mantis had this specific organ. It’s possible that other mantis species have the organ too, but that scientists just haven’t seen it yet.

As we learned in our previous mantis episodes, not only are there well over 2,000 known species of mantis alive today, there are more being discovered all the time. In 2019, Project Mantis went to Brazil to look for mantises, and not only did they find two of the extremely rare dragon mantises, they discovered what may be a species new to science. It hasn’t been described yet as far as I can find, but it appears to be a member of a group called unicorn mantises because it has a spike sticking up from the top of the head. Scientists have no idea what the spike is for, but it’s funny that they found unicorn mantises and dragon mantises in the same forest.

Late in 2023, two new species of Australian mantis were described, one of which is so different from other known species that it was placed in its own genus. They’re small mantises that live on tree trunks and are camouflaged to look like pieces of bark, so they’re hard to spot. Luckily, a citizen scientist named Glenda Walter noticed them and posted pictures to iNaturalist. A lot of scientists watch iNaturalist posts, and it’s a good thing because Glenda’s mantises turned out to be completely new to science. One of them has been named Inimia nat, which is abbreviated I. nat, which is also the abbreviation for iNaturalist. A citizen scientist is anyone who is interested in science and works to help improve scientific knowledge in general, for instance by taking pictures of interesting bugs and posting them to iNat.

The praying mantis has been around since at least the early Cretaceous, around 120 million years ago. The oldest remains found don’t look that much like modern mantises, though. They look more like cockroaches, which isn’t too surprising since mantises are closely related to cockroaches. By about 110 million years ago mantises had started to evolve the deadly front legs that they have now. Most fossilized mantis remains are actually impressions of wings, but experts can learn a lot from just the wings. Baby praying mantises have even been found preserved in amber from up to 87 million years ago.

A lot of people are scared of praying mantises because they look dangerous. They’re not dangerous to humans or pets at all, though. If you get pinched or nipped by a mantis, just wash your hands to clean out the wound and you’ll be fine. Mantises are extremely beneficial insects, especially in the garden, because they eat other insects that eat plants that humans don’t want eaten, like flowers and vegetables. Some people release mantises in the garden as a natural way to control insect pests. And, as Elijah can tell you, mantises actually make really interesting pets.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 374: PUFFERFISH!

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Thanks to River for suggesting this week’s topic, the pufferfish!

Further reading:

Grass puffer fish communicate with each other using a non-toxic version of their deadly toxin

Mystery pufferfish create elaborate circular nests at mesophotic depths in Australia

Pufferfish, puffed:

A starry puffer, un-puffed [picture by Diego Delso, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116912671]:

A grass puffer, un-puffed:

The mystery structure that turns out to be made by pufferfish:

Show transcript:

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

This week we’re going to learn about a weird fish suggested by River, the pufferfish!

Lots of fish have the name pufferfish, and sometimes they’re also called balloonfish, swellfish, bubblefish, or globefish. You might be able to guess from the names what they can do, but just in case you don’t know, the pufferfish can puff up to make itself big and round. The question you might have at this point is why, and how do they do this?

There are lots of pufferfish in various genera, all of them in the family Tetradontidae. Tetradontidae means “four teeth,” because obviously when you find an incredibly poisonous fish that can blow itself up like a balloon, sometimes with spikes that emerge from the skin, of course you’re going to name it after its teeth.

Most pufferfish live in the ocean, although some live in places where freshwater mixes with ocean water, and some species even live in rivers. It prefers warm, shallow water and eats invertebrates and plant material. Larger pufferfish can use their four big front teeth to crush the shells of mollusks, like clams and mussels.

Most pufferfish are quite small and often brightly colored with spots, stripes, and other markings. You’d think the biggest pufferfish has to be the one called the giant freshwater pufferfish, but while it is big, it’s not the biggest. The giant freshwater pufferfish can grow up to 26 inches long, or 67 cm, which is over two feet long. But the starry puffer is almost twice that length, up to 47 inches long, or 120 cm. That’s almost four feet long!

The starry puffer lives in tropical and subtropical parts of the Pacific Ocean, especially in the Indian Ocean and the Red Sea. It has a big head, two pairs of nostrils, and is a mottled gray and white in color with little black spots all over. It mostly eats crustaceans and mollusks, but will also eat algae, sponges, coral, urchins, and other invertebrates.

The pufferfish is a slow swimmer, but it has two really good defenses. If it feels threatened—for instance if a big fish tries to catch it, or it’s caught in a fishing net and hauled to the surface, or if a diver tries to make friends, the pufferfish will swell up until it looks like a balloon with fins. It does so by gulping air or water into its elastic stomach until it’s completely full.

If you’re wondering how this can help the fish, not only does this make the pufferfish look much larger, it also makes it harder to swallow. Not only that, the pufferfish has spines that may be hidden in the skin most of the time, but when the skin tightens as the fish expands into balloon shape, the spines poke out. Suddenly a potential predator isn’t just trying to swallow a fish way bigger than its mouth is, it’s pointy.

The pufferfish’s second defense is that its body contains a deadly poison. You may have heard about fugu, which is considered a delicacy even though it’s so poisonous that in Japan and some other countries, chefs have to be specially trained and licensed to prepare the fish to eat. It contains tetrodotoxin, or TTX, a neurotoxin that stops your nerves from sending the tiny electrical signals that allow muscles to move. If you’re poisoned with TTX, you start to feel dizzy and sick, then you start having difficulty speaking and moving, then you have trouble breathing, and then, ultimately, you’re paralyzed and can’t breathe, at which point you die. Since the toxin doesn’t affect your brain, you remain completely aware of what’s happening to you but there’s nothing you can do about it. There’s no antidote. Fortunately, you have the option of not eating fugu.

Not all pufferfish are poisonous, although most are, and in many species the amount of toxins in the fish’s body can vary according to the time of year and the individual fish. People who have eaten their local pufferfish many times with no problem can suddenly get sick or die from eating the same type of fish. That’s the bad type of surprise.

At least some pufferfish use their toxins for a surprising purpose. In late 2022, a study was published about the grass puffer, also called the grey-spotted puffer. It’s a small fish that grows not quite 10 inches long, or 25 cm, and is gray with tiny white spots. It’s extremely toxic but its body also contains a non-toxic version of TTX, called TDT. Scientists studying the fish determined that other grass puffers can smell TDT in the water so they can find each other. Not only that, other animals found in the same environment where the grass puffer lives also contain both TTX and TDT, and the pufferfish eats those animals. Naturally, it can find its prey by smell.

Let’s finish with a pufferfish mystery that’s been solved. In 1995, divers in southern Japan noticed a series of mysterious underwater structures in the sand. They were about six feet across, or close to two meters, round in shape, and looked sort of like someone had packed sand into a giant one of those fancy decorative cake pans that make designs around the cake, and turned it out upside down underwater. No one could figure out what they were, how they’d been made, or why they were there. People started calling them underwater crop circles.

It wasn’t until 2011 that the mystery was solved, when a diver saw one of the circles being formed by a little pufferfish. The fish turned out to be new to science and was described in 2014, and is popularly known as the white-spotted pufferfish. The male builds the structure by waving his fins to move sand into geometric shapes and concentric rings, a process that takes over a week. Since water keeps moving the sand, he has to keep working on the structure to keep it looking good, and he wants it to look good because that’s how he attracts a mate. The specific patterns he creates direct water currents to the center of the structure, where it deposits fine, soft sand. If a female likes the structure, she will lay her eggs in the soft sand in the middle so that the male can fertilize them.

In 2018, similar nests were discovered off the coast of western Australia, but so far no one knows whether the nests are built by a known species of pufferfish or a species new to science.

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