Podcast: Play in new window | Download (Duration: 1:07 — 1.2MB)
I just wanted everyone to know that a listener has claimed the books and magazines I offered for giveaway in episode 443. You can also learn about 60 seconds’ worth of information about the African pygmy mouse.
The tiniest mouse [photo by Alouise Lynch – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=59068329]:
Podcast: Play in new window | Download (Duration: 8:21 — 9.2MB)
Thanks to Jayson and warblrwatchr for suggesting this week’s invertebrates!
Further reading:
Parasite of the Day: Orthohalarachne attenuata
Trap-jaw ants jump with their jaws to escape the antlion’s den
Get out of my noooooose:
An ant lion pit:
An ant lion larva:
A lovely adult antlion, Nannoleon, which lives in parts of Africa [photo by Alandmanson – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=58068259]:
Show transcript:
Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.
It’s almost August, and of course we’re doing invertebrate August again this year. Let’s get ready by talking about a few extra invertebrates this week, with suggestions from Jayson and warblrwatchr.
Before we get started, I have some quick housekeeping. First, a big shout-out to Nora who emailed me recently. I just wanted to say hi and I hope you’re having a good day. Next, I’m moving in just a few weeks to Atlanta, Georgia! I know I was talking forever about moving to Bloomington, Indiana, but I changed my mind. The next few episodes are already scheduled so I can concentrate on moving.
I’m about 75% packed at this point and have given away or sold a lot of stuff, including a lot of books. But I have a collection that a listener might be interested in. I offered it to the patrons last month but no one grabbed it, so I’ll offer it here.
I have every issue of the little magazine Flying Snake ever published, 30 in all. They’re a fun hodgepodge of articles, reprinted newspaper clippings, old photos, and other stuff more or less associated with cryptozoology and weirdness in general. I’ve decided they take up too much space on my shelves to take with me to Atlanta. If you’re interested in giving them a home, let me know and I’ll box them up and send them to you for free. The first person who says they’ll take them will get them, but the catch is that you have to take them all. I won’t just send you a few. I’ll also throw in all four volumes of the Journal of Cryptozoology. This offer stands until mid-August when I move, because if I have to move them to my new apartment, I’m just going to keep them.
Okay, now let’s learn about some invertebrates! First, Jayson wanted to learn about a tiny invertebrate called Orthohalarachne attenuata. It doesn’t have a common name because most people will never ever encounter it, or think about it, and I kind of wish I didn’t have to think about it because it’s gross. Thanks a lot, Jayson. It’s a mite that lives in the nasal passages of seals, sea lions, and walruses. It’s incredibly common and usually doesn’t bother the seal very much, although sometimes it can cause the seal to have difficulty breathing if the infestation is heavy.
The adult mite spends its whole life anchored in the seal’s nasal passages with sharp little claws, although it can move around if it wants to. Its larvae are more active. The mite is mainly spread by seals sneezing on each other, which spreads the larvae onto another seal, and the larvae crawl into the new seal’s nose and mouth.
Unless you’re a seal or other pinniped, this might sound gross but probably doesn’t bother you too much. But consider that in 1984, a man went to the doctor when one of his eyes started hurting. The doctor found a mite attached to his eyeball, and yes, it was Orthohalarachne attenuata. The man had visited Sea World two days before he started feeling pain in his eye, and happened to be close to some walruses that were sneezing.
Luckily for pinnipeds kept in captivity in zoos that give their animals proper care, mite infestations can be treated successfully by veterinarians.
Let’s move on quickly to an invertebrate that isn’t a parasite that can get in your eyes, the ant lion! It was suggested by warblrwatchr and I’ve been wanting to cover it for a while. When I was a kid, there was a strip of soft powdery dirt under the eaves of the school gym that always had ant lions in it, and I would squat down during recess and watch to see if any ants would fall in and get caught. Sometimes this did actually happen and the resulting battle between ant and ant lion was exciting and kind of horrible to witness.
The ant lion is actually the larva of antlion lacewing, which look like a small damselfly that is mainly active at dusk. Ant lions live throughout the world, with more than 2,000 species known. Some wait for prey while hidden in leaf litter, while some hide in rock crevices and become camouflaged by lichens growing on them. Many others dig little pits in sand or soft dirt. They’re also called the doodlebug in some places, because when they’re looking for a place to dig a little pit, they make a loopy pattern in the dirt as they’re walking around.
The ant lion’s body is robust and has little backwards-pointing bristles that help it dig itself into the dirt and stay there without moving until it needs to. It waits at the bottom of the pit, hidden underground with just its long, sharp jaws showing through the dirt, until an ant or other insect falls in. The ant can’t climb out because the sides of the pit are so sharply angled that they start to cave in, sending the ant down to the bottom of the pit. If that doesn’t work, the ant lion kicks dirt at the ant so that it falls. Then the ant lion grabs the ant in its fearsome jaws and injects venom and digestive enzymes into it, and that is the end of the ant. The jaws actually have little projections that are hollow and act like horrible little straws, so that the ant lion sucks the liquefied ant insides into its digestive system.
One species of ant, the trap-jaw ant, can sometimes escape the ant lion’s pit by using its own fearsome jaws as a spring to bounce itself to safety. There are many species of trap-jaw ant that live in tropical and subtropical areas throughout much of the world, including Africa, Asia, Australia, and much of the Americas. Its long jaws can snap closed extremely quickly and with a lot of force, allowing it to kill prey, bite pieces off of food, and lots of other activities. They can also jump with their jaws, and this improves their ability to bounce right out of the ant lion pit.
The ant lion can remain in its larval stage for years, maturing slowly. It has no anus but it doesn’t expel the waste products that it can’t digest, it just stores them in its body. When it does finally pupate, it uses a lot of the waste to produce silk for its cocoon. Whatever is left over it leaves behind when it emerges from its cocoon.
The cocoons are naturally hidden underground, and when the adult antlion lacewing emerges, it digs its way to the surface and rests while its wings open. Compared to the tough little larva, the adult is delicate and not very robust. It doesn’t live very long, usually no more than a few weeks, and most species eat pollen or nectar, or maybe tiny insects. It mainly just seeks out a mate, and the female lays her eggs in soft soil. When they hatch, they build their first tiny pits and the cycle starts again. And nobody gets into anybody’s eyeballs.
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!
Podcast: Play in new window | Download (Duration: 9:19 — 10.4MB)
Further reading:
The Trees That Miss the Mammoths
The disappearance of mastodons still threatens the native forests of South America
Study reveals ancient link between mammoth dung and pumpkin pie
A mammoth, probably about to eat something:
The Osage orange fruit looks like a little green brain:
Show transcript:
Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.
Way back at the end of 2017, I found an article called “The Trees That Miss the Mammoths,” and made a Patreon episode about it. In episode 320, about elephants, which released in March of 2023, I cited a similar article connecting mammoths and other plants. Now there’s even more evidence that extinct megafauna and living plants are connected, so let’s have a full episode all about it.
Let’s start with the Kentucky coffeetree, which currently only survives in cultivation and in wetlands in parts of North America. It grows up to 70 feet high, or 21 meters, and produces leathery seed pods so tough that most animals literally can’t chew through them to get to the seeds. Its seed coating is so thick that water can’t penetrate it unless it’s been abraded considerably. Researchers are pretty sure the seed pods were eaten by mastodons and mammoths. Once the seeds traveled through a mammoth’s digestive system, they were nicely abraded and ready to sprout in a pile of dung.
There are five species of coffeetree, and the Kentucky coffeetree is the only one found in North America. The others are native to Asia, but a close relation grows in parts of Africa. It has similar tough seeds, which are eaten and spread by elephants.
The African forest elephant is incredibly important as a seed disperser. At least 14 species of tree need the elephant to eat their fruit in order for the seeds to sprout at all. If the forest elephant goes extinct, the trees will too.
When the North American mammoths went extinct, something similar happened. Mammoths and other megafauna co-evolved with many plants and trees to disperse their seeds, and in return the animals got to eat some yummy fruit. But when the mammoths went extinct, many plant seeds couldn’t germinate since there were no mammoths to eat the fruit and poop out the seeds. Some of these plants survive but have declined severely, like the Osage orange.
The Osage orange grows about 50 or 60 feet tall, or 15 to 18 meters, and produces big yellowish-green fruits that look like round greenish brains. Although it’s related to the mulberry, you wouldn’t be able to guess that from the fruit. The fruit drops from the tree and usually just sits there and rots. Some animals will eat it, especially cattle, but it’s not highly sought after by anything. Not anymore. In 1804, when the tree was first described by Europeans, it only grew in a few small areas in and near Texas. The tree mostly survives today because the plant can clone itself by sending up fresh sprouts from old roots.
But 10,000 years ago, the tree grew throughout North America, as far north as Ontario, Canada, and there were seven different species instead of just the one we have today. 10,000 years ago is about the time that much of the megafauna of North and South America went extinct, including mammoths, mastodons, giant ground sloths, elephant-like animals called gomphotheres, camels, and many, many others.
The osage orange tree’s thorns are too widely spaced to deter deer, but would have made a mammoth think twice before grabbing at the branches with its trunk. The thorns also grow much higher than deer can browse. Trees that bear thorns generally don’t grow them in the upper branches. There’s no point in wasting energy growing thorns where nothing is going to eat the leaves anyway. If there are thorns beyond reach of existing browsers, the tree must have evolved when something with a taller reach liked to eat its leaves.
The term “evolutionary anachronism” is used to describe aspects of a plant, like the Osage orange’s thorns and fruit, that evolved due to pressures of animals that are now extinct. Scientists have observed evolutionary anachronism plants throughout the world. For instance, the lady apple tree, which grows in northern Australia and parts of New Guinea. It can grow up to 66 feet tall, or 20 meters, and produces an edible red fruit with a single large seed. It’s a common tree these days, probably because the Aboriginal people ate the fruit, but before that, a bird called genyornis was probably the main seed disperser of the lady apple.
In episode 217 we talked about the genyornis, a flightless Australian bird that went extinct around 50,000 years ago but possibly more recently. It grew around 7 feet tall, or over 2 meters, and recent studies suggest it ate a lot of water plants. It would have probably eaten the lady apple fruit whenever it could, most likely swallowing the fruits whole and pooping the big seeds out later.
Way back in episode 19 we talked about a tree on the island of Mauritius that relied on the dodo’s digestive system to abrade its seeds so they could sprout. It turns out that study was flawed and the seeds don’t need to be abraded to sprout. They just need an animal to eat the flesh off the seed, either by just eating the fruit and leaving the seed behind, or by swallowing the entire fruit and pooping the seed out later, and that could have been done by any number of animals. The dodo probably did eat the fruits, but so did a lot of other animals that have also gone extinct on Mauritius.
In June of 2025, a study was published showing that the gomphothere Notiomastodon, which lived in South America until about 10,000 years ago, definitely ate fruit. Notiomastodon was an elephant relation that could probably grow almost ten feet tall, or 3 meters. It probably lived in family groups like modern elephants and probably looked a lot like a modern elephant, at least if you’re not an elephant expert or an elephant yourself. The 2025 study examined a lot of notiomastodon teeth, and it discovered evidence that the animals ate a lot of fruit. This means it would have been an important seed disperser, just like the African forest elephant that we talked about earlier.
Another plant that nearly went extinct after the mammoth did is a surprising one. Wild ancestors of modern North American squash plants relied on mammoths to disperse their seeds and create the type of habitat where the plants thrived. Mammoths probably behaved a lot like modern elephants, pulling down tree limbs to eat and sometimes pushing entire trees over. This disturbed land is what wild squash plants loved, and if you’ve ever prepared a pumpkin or squash you’ll know that it’s full of seeds. The wild ancestors of these modern cultivated plants didn’t have delicious fruits, though, at least not to human taste buds. The fruit contained toxins that made them bitter, which kept small animals from eating them. Small animals would chew up the seeds instead of swallowing them whole, which is not what the plants needed. But mammoths weren’t bothered by the toxins and in fact probably couldn’t even taste the bitterness. They thought these wild squash were delicious and they ate a lot of them.
After the mammoth went extinct, the wild squash lost its main seed disperser. As forests grew thicker after mammoths weren’t around to keep the trees open, the squash also lost a lot of its preferred habitat. The main reason why we have pumpkins and summer squash is because of our ancient ancestors. They bred for squash that weren’t bitter, and they planted them and cared for the plants. So even though the main cause of the mammoth’s extinction was probably overhunting by ancient humans, at least we got pumpkin pies out of the whole situation. However, I personally would prefer to have both pumpkin pie and mammoths.
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!
Podcast: Play in new window | Download (Duration: 11:25 — 12.8MB)
Thanks to Maryjane and Siya for their suggestions this week!
Further reading:
Look, don’t touch: birds with dart frog poison in their feathers found in New Guinea
The hooded pitohui:
The rufous-naped bellbird:
The regent whistler:
Show transcript:
Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.
This week we’re going to learn about some birds that by human standards seem pretty mean, although of course the birds are just being birds. Thanks to Maryjane and Siya for their suggestions this week!
We’ll start with Maryjane’s suggestion, the Northern shrike. It lives in North America, spending winter in parts of Canada and the northern United States. In summer it migrates to northern Canada. It’s a lovely gray and black bird with a dark eye streak, white markings on its tail and wings that flash when it flies, and a hooked bill. It’s a strong bird about the size of an American robin, and both the male and female sing. They will sometimes imitate other bird songs, and during breeding season a pair will sing duets. The Northern shrike looks very similar to the loggerhead shrike that lives farther south, in the southern parts of Canada and throughout most of the United States and Mexico.
Most important to us today, the Northern shrike is sometimes called the butcher bird, because in the olden days, butchers would hang meat up to cure–but we’ll get to that part.
It prefers to live in the edges of a forest near open spaces, and in the summer it lives along the border of the boreal forest and tundra. While it’s just a little songbird, in its heart it’s a falcon or hawk. It eats a lot of insects and other invertebrates, especially in summer, but it mainly kills and eats other songbirds and small mammals like mice and lemmings, even ones that are bigger and heavier than it is.
The shrike has ordinary feet for a perching bird, not talons, but its feet are strong and can hold onto struggling prey. Its beak is deadly to small animals. The bill has a sharp hook at the end and is notched so that it has two little projections that act like fangs. It will hover and drop onto its prey, or grab a bird in mid-flight and bear it to the ground to kill it. Sometimes it will hop along the ground until it startles a bird or insect into flying away. It will even flash the white patches on its wings to frighten hidden prey into moving.
If the shrike kills a wasp or bee, it will remove the stinger before eating it. It will pick off the wings of large insects and will sometime beat a dead insect against a rock or branch to soften it up and break off parts of the hard exoskeleton before eating it.
Shrikes are territorial and will chase away birds that are much bigger than them, like ducks and even geese. During nesting season, the female takes care of the eggs and the male provides food for her. To prove that he can provide lots of food for the female while she’s incubating the eggs, he will cache food throughout his territory in advance. This is something shrikes do anyway, but it’s especially important during nesting season.
If a shrike catches an animal it doesn’t want to eat right away, it will store it for later. It will cram it into a crack in a rock, impale it on a thorn or other sharp item like the points of a barbed wire fence, or wedge it into the fork of a tree branch. Then it can come back and eat it in a day or two when it’s hungry, or take the food to its mate.
When the eggs hatch, both parents help feed the babies. When the babies are old enough to leave the nest, the parents go their separate ways, but they will often each take some of the fledglings with them so they can continue to feed them and help them learn to hunt. Since a nest can have as many as nine babies, it’s not always possible for one parent to take all the babies. The siblings stick together even once they’re mostly grown and independent, often through their first winter.
This is what a Northern shrike sounds like:
[Northern shrike call]
We talked about some poisonous birds in episode 222, but Siya wanted to learn more about them. In that episode we mostly talked about the hooded pitohui, but since then, two more poisonous birds have been discovered in New Guinea.
Let’s refresh our memories about the hooded pitohui, mostly because its discovery by scientists is such a fun story.
The hooded pitohui lives in forests throughout much of New Guinea and eats seeds, insects and other invertebrates, and fruit. It’s related to orioles and looks very similar, with a dark orange body and black wings, head, and tail. It’s a social songbird that lives in family groups where everyone works to help raise the babies.
The people who live in New Guinea knew all about its toxicity, of course. They mentioned this to European naturalists as long ago as 1895, but weren’t believed, because the scientists had never heard of a toxic bird. It wasn’t until 1989 that a grad student studying birds of paradise made a surprising discovery.
Jack Dumbacher was trying to net some birds of paradise to study but kept catching pitohuis in his nets. He would untangle the birds and let them fly away, but naturally they were upset and one scratched him. He was in a hurry so he just licked the cuts clean. His tongue started to tingle, then burn, and then it went numb.
Fortunately the effects didn’t last long, but he mentioned it to another researcher who had had a similar experience. They realized something weird was going on, so Dumbacher asked some of the local people what the cause might be. They all said, “Yeah, don’t lick the pitohui bird.”
Dumbacher did, though, because sometimes scientists have to lick things. The next time his nets caught a pitohui, Dumbacher plucked one of its feathers and put it in his mouth. His mouth immediately started to burn.
Dumbacher was amazed to learn about a toxic bird, but it took a year for anyone else to take an interest, specifically Dr. John W. Daly, an expert in poison dart frogs in Central and South America. Back in the 1960s while he was studying the frogs, in order to determine which ones were actually toxic and which ones weren’t, he frequently poked a frog and licked his finger, so Daly completely understood Dumbacher putting a feather in his mouth.
Maybe don’t put random stuff in your mouth. Both Dumbacher and Daly were lucky they didn’t die, because it turns out that poison dart frogs and pitohuis both contain one of the deadliest neurotoxins in the world, called batrachotoxin.
A chemical analysis determined that both animals excrete the same toxin. In captivity, poison dart frogs lose their toxicity. Daly was the one who figured this out, but he couldn’t figure out why except that he was pretty sure they absorbed the toxins from something they were eating in the wild. He thought the same might be true for the pitohui.
Dumbacher agreed, and after he achieved his doctorate he started making expeditions to New Guinea to try to find out what. Both he and Daly thought it was probably an insect. But there are a lot of insects in Papua New Guinea and he couldn’t stay there and test insects for toxins all the time. He came and went as often as he could, and to make his trips easier he left his equipment in a village rather than hauling it back and forth with him.
What he didn’t know is that one villager, named Avit Wako, had gotten interested in the project. When Dumbacher was gone, he continued the experiments. In 1995 Dumbacher sent a student intern to the village, since he didn’t have time to go himself, and Avit Wako said, “Hey, good to see you! I solved your problem. The toxin comes from this particular kind of beetle.” He was right, too. The toxin comes from beetles in the genus Choresine.
But the pitohui isn’t the only toxic bird in New Guinea. In 2018 and 2019, two researchers from the University of Copenhagen in Denmark got interested in poisonous birds and did some studies. One of the scientists is Kasun Bodawatta, whose colleagues thought he was having a rough time during the trip. The life of a scientist in the field can be hard, and Bodawatta kept having issues with a runny nose and weepy eyes. It wasn’t allergies or exhaustion, though, but the result of handling poisonous birds and their feathers. He described it as feeling “like cutting onions, but with a nerve agent.”
Bodawatta’s team discovered that two more birds in New Guinea contain the same toxins as the pitohui in their feathers and skin. The rufous-naped bellbird is gray-brown with white and yellow markings, and a patch of rufous on the back of its head. The regent whistler is black and yellow with a white patch on its throat. Both eat insects as a large part of their diets, and both show similar genetic mutations that allow them to sequester the Choresine toxins in their feathers and skin. Not only does this keep potential predators from eating the birds, it also probably helps kill mites and other parasites that might otherwise want to live in their feathers.
A 2023 study on the birds’ toxins discovered something new. In addition to the neurotoxin the birds absorb from beetles, the regent whistler’s skin also contains a different toxin that doesn’t have anything to do with beetles or other insects. The regent whistler’s skin glands contain a population of symbiotic bacteria that secrete a completely different toxin made of previously unknown molecules. The toxin helps protect the birds from harmful bacteria and fungi that are known to infect the skin and feathers of birds.
In 2024, a team of microbiologists and chemists began studying the antimicrobial secretions in hopes of creating a new type of antimicrobial drug for use in humans and other animals. So thank you, little birds, and thank you to the scientists and citizen scientists who study them.
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!
Podcast: Play in new window | Download (Duration: 10:27 — 11.7MB)
Thanks to Micah for suggesting this week’s topic, the trilobite!
Further reading:
Stunning 3D images show anatomy of 500 million-year-old Cambrian trilobites entombed in volcanic ash
Strange Symmetries #06: Trilobite Tridents
A typical trilobite:
Isotelus rex, the largest trilobite ever found [photo from the first link above]:
Walliserops showing off its trident [picture by TheFossilTrade – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=133758014]:
Another Walliserops individual with four prongs on its trident [photo by Daderot, CC0, via Wikimedia Commons]:
Show transcript:
Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.
This week we’re going to learn about an ancient animal that was incredibly successful for millions of years, until it wasn’t. It’s a topic suggested by Micah: the trilobite.
Trilobites first appear in the fossil record in the Cambrian, about 520 million years ago. They evolved separately from other arthropods so early and left no living descendants, that they’re not actually very closely related to any animals alive today. They were arthropods, though, so they’re distantly related to all other arthropods, including insects, spiders, and crustaceans.
The word trilobite means “three lobes,” which describes its basic appearance. It had a head shield, often with elaborate spikes depending on the species, and a little tail shield. In between, its body was segmented like a pillbug’s or an armadillo’s, so that it could flex without cracking its exoskeleton. Its body was also divided into three lobes running from head to tail. Its head and tail were usually rounded so that the entire animal was roughly shaped like an oval, with the head part of the oval larger than the tail part. It had legs underneath that it used to crawl around on the sea floor, burrow into sand and mud, and swim. Some species could even roll up into a ball to protect its legs and softer underside, just like a pillbug.
Because trilobites existed for at least 270 million years, there were a lot of species. Scientists have identified about 22,000 different species so far, and there were undoubtedly thousands more that we don’t know about yet. Most are about the size of a big stag beetle although some were tinier. The largest trilobite found so far lived in what is now North America, and it grew over two feet long, or more than 70 centimeters, and was 15 inches wide, or 40 cm. It’s named Isotelus rex.
I. rex had 26 pairs of legs, possibly more, and prominent eyes on the head shield. Scientists think it lived in warm, shallow ocean water like most other trilobites did, where it burrowed in the bottom and ate small animals like worms. There were probably other species of trilobite that were even bigger, we just haven’t found specimens yet that are more than fragments.
Because trilobites molted their exoskeletons the way modern crustaceans and other animals still do, we have a whole lot of fossilized exoskeletons. Fossilized legs, antennae, and other body parts are much rarer, and preserved soft body parts are the rarest of all. We know that some trilobite species had gills on the legs, some had hairlike structures on the legs, and many had compound eyes. A specimen with preserved eggs inside was also found recently.
Some incredibly detailed trilobite fossils have been found in Morocco, including details like the mouth and digestive tract. The detail comes from volcanic ash that fell into shallow coastal water around half a billion years ago. The water cooled the ash enough that when it fell onto the trilobites living in the water, it didn’t burn them. It did suffocate them, though, since so much ash fell that the ocean was more ash than water.
The ash was soft and as fine as powder, and it covered the trilobites and protected their bodies from potential damage, while also preserving the body details as they fossilized over millions of years. The fossils were discovered in 2015, about 509 million years after the trilobites died, and are still being studied.
Two species of trilobite have been found at this Morocco site, and the team is using non-invasive technology to study the preserved insides in one exceptionally preserved specimen. Its entire digestive system is intact, probably because the poor trilobite ended up swallowing a lot of ash before it died. The ash kept the soft tissues from decomposing.
Some trilobites had spines growing from their head shields and even from the rest of the exoskeleton. Scientists think these may have helped protect the animals from being eaten, but they might also have helped them navigate more easily in the water without getting flipped over by currents. One genus of trilobite, Walliserops, even had a structure sticking out from the front of its head called a trident.
The trident grew forward and slightly upward from the head, then split into three prongs. Scientists aren’t sure what it was for, but suggest that it acted as a nose spike like some modern beetles have, which allowed trilobites to fight each other for resources or mates. The tridents weren’t completely symmetrical, and one individual has even been found with a four-pronged trident. (I guess you would call that a quadrent.) Some species had long tridents, some short, but there’s no evidence that only males or only females had them.
Electron microscopes and other modern imaging technology have allowed scientists to learn more about what the trilobite looked like when it was alive. This includes some hints about different species’ coloration and markings. Most trilobites had good vision and were probably as colorful as modern crustaceans. Some rare trilobite fossils show microscopic traces of spots and stripes. One species studied may have had a brown stripe that faded to white along the edges of the body.
All trilobites went extinct at the end of the Permian, about 250 million years ago, during the extinction event called the Great Dying. We talked about it in detail in episode 227 so I won’t go over its causes and effects again except to say that an estimated 95% of all marine animals went extinct during that event. The Great Dying ended the trilobite’s successful 270 million year run on this amazing planet.
When I was little, I found trilobites fascinating. They were so common for so long, and then they were gone. I’ve always wondered if some trilobites survived the Great Dying and were still alive in the deep sea. I’m not the only one who’s wondered that, so let’s talk a little more about why the trilobites went extinct and how some of them might have survived.
Almost all trilobites we know of lived in shallow coastal water. We have trilobite tracks of an ancient low tide shore, which tells us that at least some species could leave the water and venture onto land occasionally, possibly the first animals on earth to do so. Coastal water is well oxygenated and we know trilobites had trouble surviving anoxic events, when the water where they lived had much less oxygen than usual. Anoxic events are actually what led to the Great Dying, but it wasn’t the first time the world’s oceans became less oxygenated. It happened in earlier extinction events too during the Devonian, around 372 and 359 million years ago, and each time many species and genera of trilobites went extinct. The trilobite was already in decline when the Great Dying occurred, with only a handful of genera left, and the extinction event finished them off once and for all according to the fossil record.
But we do know of a few species of trilobite that were adapted to the deep sea. Deep-sea animals have to evolve to be tolerant of low-oxygen conditions. The deep sea is also very little known by humans. It’s possible, even if it’s unlikely, that deep-sea trilobites survived the Great Dying and that their descendants are still around, unknown to science.
One interesting note, and an ongoing mystery about trilobites, is that while we know they were arthropods, we don’t actually know which branch of the phylum Arthropoda they’re most related to. That’s because there are no ancestral versions of the trilobite that have ever been found. When they appear in the fossil record, they’re already recognizably trilobites. It’s possible that the ancestral forms didn’t have exoskeletons that were likely to fossilize, or that we just haven’t found the right fossil bed yet. Until we learn more, it’ll remain a mystery.
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