Tag Archives: barbeled dragonfish

Episode 231: Fish of the Twilight Zone

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Let’s learn about some strange fish of the mesopelagic, or the twilight zone deep in the ocean! Thanks to Page, Joel, Anonymous Animal Lover, Brigham, and Fireburster for suggestions this week!

Further reading:

In Defense of the Blobfish

Further viewing:

Pacific viperfish (video embedded)

The Pacific viperfish, head-on (or rather teeth-on), still from video linked above:

Sloane’s viperfish, rocking those teeth:

The blobfish as it’s usually seen on the internet:

The blobfish as it looks when it’s cozy in its deep-sea environment:

The barreleye, which I have helpfully labeled for you:

Look at the bristlemouth’s sharp thin teeth! Good thing it’s only a few inches long:

An indignant bristlemouth (someone should take MS Paint away from me):

The bristlemouth is the most abundant vertebrate in the WORLD (photo by Paul Caiger):

Show transcript:

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

Where on earth does the time go? Suddenly we’re halfway through 2021 and I’m still vaguely thinking we’re only a few months in. I’m getting seriously behind on listener suggestions, so let’s have an episode about some weird fish that’s all listener suggestions. Thanks to Page, Joel, an animal lover who wants to remain anonymous, Brigham (whose name I hope I’m pronouncing correctly), and someone who calls themself Fireburster. Fireburster and Anonymous Animal Lover also both left us really nice reviews, so thank you! I picked all these suggestions at random, just grabbing fish suggestions that sounded interesting, but the great thing is they all turned out to live in a specific part of the deep sea.

Brigham and Fireburster both suggested the same fish, so let’s start with that one: the dragon fish. Neither of them specified which kind of dragon fish they’re talking about, though. It’s a popular name for weird fish of various kinds. We’ve even talked about a few before, the Pacific blackdragon of episode 193, which was coincidentally suggested by Page, and the barbeled dragonfish in that same episode. That’s the episode about William Beebe’s mystery fish, which happens to be my current favorite.

We only talked about the barbeled dragonfish briefly before, so let’s learn more about them now.

The barbeled dragonfish gets its name from the filament that hangs down from its chin, called a barbel. If you’ve ever wondered what the proper name for a catfish’s whiskers is, they’re also barbels. The dragonfish’s barbel has a photophore at the end that produces blue-green bioluminescent light, and the fish flashes the light to attract prey. Its head is large and its jaws are full of sharp teeth, so when an animal comes close, CHOMP! The barbeled dragonfish grabs it.

The dragonfish isn’t very big, with the blackdragon that we talked about in episode 193 being the largest at only 16 inches long, or 40 cm. Most species are about half that. So what happens when an animal the same size as or even bigger than the dragonfish happens along?

The dragonfish eats it, that’s what happens. It has large jaws that it can unhinge to swallow prey that’s bigger than it is, and its stomach can expand considerably to hold whatever it swallows. Mostly it just eats tiny animals like krill and amphipods, though.

We don’t know a whole lot about dragonfish. Various species live throughout most of the world’s oceans, especially in tropical and subtropical areas, and they don’t live in the deepest parts of the ocean. Instead, they’re found in what’s called the twilight zone, or more properly the mesopelagic. Only 1% of all light shining down from the surface makes it down this far, which is why so many animals produce their own bioluminescent light. The dragonfish also has photophores along its sides that it can flash to help attract prey or attract mates. On nights when the moon isn’t too bright, the dragonfish will migrate closer to the surface to find more food, but it makes sure to go back to the twilight zone before the sun rises.

[twilight zone music]

One genus of dragonfish is called the viperfish, and they’re a little different from other dragonfish. Instead of a barbel on the chin, viperfish have a light at the end of a long spine that’s a modified dorsal fin. This is similar to the anglerfish we’ve talked about many times before, even though dragonfish and anglerfish aren’t related. Convergent evolution, at it again!

The viperfish has teeth so long they don’t fit in its mouth. Instead, they stick out, which gives it its other name of fangfish. Sloane’s viperfish has the largest teeth of all the viperfish species, so long that they form a cage across its mouth to stop prey from escaping before the fish can swallow it. Unlike most dragonfish, Sloane’s viperfish sometimes swims toward its prey very quickly, slamming into it and wounding it with its fangs. It even has a sort of built-in shock absorber in its spine right behind its head. The Pacific viperfish can also be aggressive when hunting.

This is probably a good place to learn a little more about the twilight zone, AKA the mesopelagic. It’s measured not by depth but by how much light is available from the surface, in this case only 1% of light. There’s also not as much oxygen in the water here as at the surface. Many, if not most, animals that live in the mesopelagic migrate closer to the surface at night to find food, then retreat to the darkness below to avoid being seen as the sun rises and fills the upper layers of water with more light.

Lots and lots of animals live in the mesopelagic, from giant squid to oarfish, although most of the animals here are small. Below this layer of water is the bathypelagic, and below that is the real depths, the abyssopelagic where conditions are extreme and life gets really weird and scarce. The uppermost layer of the ocean is called epipelagic, if you were wondering. No plants live in the mesopelagic or below, because there’s not enough light. Obviously, the ocean isn’t always deep enough to have a bathypelagic layer or below, and quite often the mesopelagic ends at the sea floor.

It’s hard to study mesopelagic animals because many of them can’t survive at the surface. They’re built to withstand the increased water pressure at depths up to 3,300 feet, or 1000 meters, below the surface, and when they’re dragged up in nets they often die within minutes. Many marine animals have an organ called a swim bladder that’s filled with gases, which helps the animal stay neutrally buoyant in the water so it doesn’t float upward or sink downward when it’s not moving. The animal can adjust the amount of gas in its bladder as it swims upward, but when it’s pulled upward quickly in a net it can’t expel enough gas fast enough and the swim bladder can burst or expand so much that it squishes the rest of its insides, killing the animal before it even reaches the surface. Animals that don’t migrate vertically often don’t have a swim bladder since they don’t need it, and they’re just adapted for water pressure that’s as much as 120 times greater than pressure at the surface. This pressure difference is why blobfish look so blobby, so let’s talk about the blobfish next, Anonymous’s suggestion.

The blobfish lives on the sea floor in deep water near Australia and New Zealand. It grows about a foot long at most, or 30 cm, and is grayish with little spikes all over it. It has a gelatinous body with weak muscles and a weak skeleton, but it doesn’t need either since the intense pressure of the water presses in around the fish all the time and keeps it just the way it should be. It looks like a fish. Its gelatinous flesh is slightly less dense than the water around it, which means it can float just above the sea floor without much effort, just drifting along, giving its tail and broad fins a little flap every so often. It eats whatever detritus floats down from far above, although it’s also mostly on the lookout for small crustaceans that live on the sea floor.

The problem comes when a fishing net catches a blobfish and brings it to the surface. Suddenly there’s no nice firm water around the fish. Instead of being slightly less dense than the water around it, the blobfish is suddenly way more dense than the water, and it expands as a result. Then someone looks at this horrible dead pinkish blob that was once a happy live fish and thinks, “Gross! I’ll take a picture of that for the internet,” and that’s why the blobfish gets its name. Poor blobfish!

Fortunately, scientists have developed a compression chamber for the animals they study. When a deep-sea animal is put in the compression chamber and brought to the surface, the compression chamber keeps the water pressure where the animal needs it. The animal doesn’t die horribly, and that allows researchers to observe a live animal instead of a dead blobby one.

Next, let’s learn about Page’s suggestion, the barreleye fish. It lives in the North Pacific in deep water, and it has upward-pointing eyes that are very sensitive to light. It’s a small fish, only about six inches long, or 15 cm, and is mostly dark in color, as you would expect from a deep-sea fish. It’s chonky in shape with large fins that help it stay motionless in the water while it looks for tiny fish and jellyfish silhouetted against the water’s surface far above. Then the barreleye will move quickly to grab its prey.

It seems like there’s something I’m forgetting to tell you. Hmm. There’s something unusual about the barreleye fish, I just know it.

Oh yeah. The domed top of its head is transparent and its eyeballs are inside the dome. You can see the internal eyeballs and its brain through its transparent head, which is otherwise filled with liquid. It is really weird-looking. Its eyes are tubular, which gives it its name, and they can rotate around to focus on things or look straight ahead when it wants to. The eyes also have bright green lenses, which helps filter out the faint sunlight from above so the fish can better see the bioluminescent glow of other deep-sea animals.

It wasn’t until 2004 that researchers realized the barreleye’s eyes were covered by the transparent dome, because it’s fragile and would end up destroyed when a fish was dragged up by nets. The first photographs and video of the barreleye in its natural environment, taken by deep-sea remote vehicles, must have freaked the researchers out completely.

If you’re wondering why the barreleye has its eyeballs hidden inside a transparent dome, researchers have wondered that too. The best guess is that the dome protects the large, sensitive eyes from jellyfish stings, since barreleyes love to eat jellyfish.

Finally, Joel suggested the bristlemouth fish. The bristlemouth is a small, slender fish that generally grows no longer than a person’s finger, although one species grows up to 14 inches long, or 36 cm. Males are smaller than females. It lives throughout the world’s oceans and is black or dark brown to hide it in the twilight zone where it lives. Like the barbeled dragonfish, which by the way really likes to eat it, it migrates closer to the surface at night to find food, then goes deeper again in the daytime to hide in the darkness.

The bristlemouth gets its name from its teeth, as you may have guessed. It has a large mouth lined with lots of short, thin teeth. It mostly eats small crustaceans, especially copepods, but will also grab tiny fish and other animals. Its lower jaw is longer than its upper jaw and can open wide to grab animals larger than it is. Unlike the other fish we’ve talked about today, its eyes are small and it doesn’t use them to find prey. Instead, it uses its lateral line system, which allows it to detect tiny movements in the water. The male bristlemouth also has a good sense of smell to help it find a female. All bristlemouths start out life as male, but some males metamorphose into females as they age.

The bristlemouth also has rows of light-emitting photophores on its underside to help hide it from predators. Its photophores glow to match the amount of light shining down from far above, which means its silhouette is much harder to see by fish or other animals below it.

There’s still a lot we don’t know about the bristlemouth, but we do know one thing. It’s the most abundant fish in the ocean. Literally there are more bristlemouths in the world than any other vertebrate, estimated at hundreds of trillions of them, possibly as many as a quadrillion, which is a million billion. That’s a lot of fish. There are so many that Navy sonar bounces off them and looks like a false bottom of the ocean. The United States Navy calls it the Deep Scattering Layer and wasn’t sure what was causing it, but the mystery was solved in 2010 when a research vessel with fine-mesh nets kept bringing up unbelievable numbers of the tiny fish. Specifically, the abundant ones are bristlemouth fish in the genus Cyclothone, which mostly lives in tropical areas.

The first person to see a bristlemouth in its natural habitat was William Beebe in the 1930s, during a bathysphere descent into the twilight zone, which brings us right back to where we started this episode.

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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

Thanks for listening!

Episode 193: Beebe’s Mystery Deep-Sea Fish

This week we’ll learn about five mystery fish that William Beebe spotted from his bathysphere in the early 1930s…and which have never been seen again. Thanks to Page for suggesting deep-sea fish!

Further reading:

How some superblack fish disappear into the darkness of the deep sea

The Fine Art of Exploration

Further listening:

99% Invisible “Bathysphere”

The Gulper Eel unlocked patreon episode

These two guys crammed themselves into that little bathysphere together. Sometimes they got seasick and puked in there. Also, they didn’t like each other very much:

The Pacific blackdragon is hard to photograph because it’s SUPERBLACK:

A larval blackdragon. Those eyestalks!

A painting (by Else Bostelmann) of Bathysphaera intacta (left) and an illustration from Beebe’s book Half Mile Down:

The pallid sailfish, also painted by Bostelmann:

A (dead) stoplight loosejaw. Tear your surprised eyeballs away from its weird jaws and compare its tail to the pallid sailfish’s:

A model of a loosejaw (taken from this site) to give you a better idea of what it looks like when alive. Close-up of the extraordinary jaws (seen from underneath) is on the right:

Show transcript:

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

This week we’re going to descend metaphorically into the depths of the ocean and learn about some mystery fish spotted once from a bathysphere by famous naturalist William Beebe and never seen again. Deep-sea fish is a suggestion by Page, so thank you, Page, for a fascinating and creepy addition to monster month.

William Beebe was an American naturalist born in 1877 who lived until 1962, which is amazing considering he made repeated dives into the deep sea in the very first bathysphere in the early 1930s. We talked about bathyspheres way back in episode 27–you know, the one where I scream about them imploding and kind of freak out a little. Even today descending into the deep sea is dangerous, and a hundred years ago it was way way way more dangerous.

Beebe was an early conservationist who urged other scientists to stop shooting so many animals. Back then if you wanted to study an animal, you just went out and killed as many of them as you could find. Beebe pointed out the obvious, that this was wasteful and didn’t provide nearly as much information as careful observation of living animals in the wild. He also pioneered the study of ecosystems, how animals fit into their environment and interact with it and each other.

While Beebe mostly studied birds, he was also interested in underwater animals. Really, he seems to have been interested in everything. He studied birds all over the world, was a good taxidermist, and especially liked to study ocean life by dredging small animals up from the bottom and examining them. He survived a plane crash, was nearly killed by an erupting volcano he was observing, and fought in WWI. Once when he broke his leg during an expedition and had to remain immobilized, he had his bed carried outside every day so he could make observations of the local animals as they grew used to his presence.

In the 1920s, during an expedition to the Galapagos Islands, he started studying marine animals more closely. First he just dangled from a rope over the surface of the ocean, which was attached to a ship’s boom, but eventually he tried using a diving helmet. This was so successful that he started thinking about building a vessel that could withstand the pressures of the deep sea.

With the help of engineer Otis Barton, the world’s first bathysphere was invented and Barton and Beebe conducted dozens of descents in Bermuda, especially off the coast of Nonsuch Island. The bathysphere had two little windows and a single light that shone through one of the windows, illuminating the outside just enough to see fish and other animals. The bathysphere couldn’t descend all that deeply, although it set records repeatedly. The deepest they descended was 3,028 feet, or 923 meters, but Beebe made careful notes of all the animals he observed and published many articles and books about them. Many of these articles and books were illustrated by an artist named Else Bostelmann, who worked closely with Beebe and his team of scientists. Bostelmann even painted underwater while wearing a diving helmet, because she needed to know how colors were affected by underwater light. She used oil paints, since oil and water don’t mix so the paints wouldn’t wash away, and she tied strings to her paintbrushes so they wouldn’t float off.

Incidentally, if you’re interested in reading a really interesting article about Bostelmann or learning more about the bathysphere and William Beebe, check the show notes. I’ve included links to the article and to a 99% Invisible episode about the bathysphere.

Many of the animals Beebe saw from the bathysphere have since been identified and described by later scientists. But there are five fish that Beebe observed that have never been seen since.

Before we talk about them, let’s learn about Page’s suggestion, the Pacific blackdragon, for reasons that will shortly become clear. The Pacific blackdragon is a type of fish that lives in the Pacific, which you probably figured out without me telling you. It prefers tropical and temperate water, although since it’s a deep-sea fish the water where it lives is mostly very cold.

If you remember episode 155 about extreme sexual dimorphism, where the males and females of a species look radically different, this fish is a good example. The male never eats. He can’t eat. He doesn’t have a functioning digestive system. He survives on the yolk from the egg he develops from and never grows any larger than his larval form, about three inches long, or 8 cm. He lives long enough to mate and then he dies.

The female, however, grows up to about two feet long, or 61 cm. Her body is long and thin, and her mouth is full of sharp teeth that she uses to grab anything she can catch. She especially likes to eat fish and small crustaceans, but she’s not picky.

Her body is black, and not just regular black. It’s called superblack or ultrablack. In episode 186 we talked about the eyed click beetle and velvet asity who both have superblack markings that absorb most of the light that hits them. Well, the Pacific blackdragon is superblack almost all over to help hide in the darkness of the water, since it’s an ambush predator. Just under the fish’s skin, there’s a layer of closely packed pigment-containing structures called melanosomes, which can absorb up to 99.95% of light. As if that wasn’t enough, because a lot of the animals the blackdragon eats emit bioluminescent light, her stomach is also black to block any light from the prey she’s swallowed. But although she’s basically invisible to other animals, she does have several rows of light-emitting cells called photophores along her sides. Scientists think she uses the lights to attract a mate, but she only flashes the photophores occasionally and only for brief moments. She also has a barbel that hangs from her chin with a luminescent lure at the end, which she uses to attract prey.

While the Pacific blackdragon is a deep-sea fish, at night she migrates upward nearer the surface to catch more prey, although she still stays below about 1,300 feet deep, or 400 m. She has large eyes as a result to take advantage of any moonlight and starlight that shines down that far. During the day she stays deeper, up to 3,200 feet deep, or 1,000 m.

Speaking of the Pacific blackdragon’s eyes, larval blackdragons have eyes on long stalks—really long stalks, nearly half their body length. As the larva matures, it absorbs the stalks until the adult fish has ordinary fish eyes. The larvae are also mostly transparent.

There are two other blackdragon species known, both of them a little smaller than the Pacific blackdragon. But in 1932 William Beebe spotted a fish that he thought might be related to the blackdragons, except that he estimated it was six feet long, or 1.8 m.

Beebe named the fish Bathysphaera intacta, but there’s no type specimen so no one can study it and verify whether it’s a species of blackdragon or something else. Beebe said the fish he saw had large eyes, lots of teeth, and photophores along its sides that glowed blue, and had a barbel with a light under its chin just like the Pacific blackdragon and its cousins. But it also had another, smaller barbel with a light near the tail. Beebe saw two of the fish together. They circled the bathysphere a few times, probably attracted to its light.

Another of Beebe’s mystery fish is one he named the pallid sailfin, Bathyembryx istiophasma. He saw it twice on the same descent in 1934, and described it as about two feet long, or 61 cm, shaped like a cigar with triangular fins and a tiny tail. In fact, in his book Half Mile Down Beebe described the fish this way:

“The strange fish was at least two feet in length, wholly without lights or luminosity, with a small eye and good-sized mouth. Later, when it shifted a little backwards I saw a long, rather wide, but evidently filamentous pectoral fin. The two most unusual things were first, the color, which, in the light, was an unpleasant pale olivedrab, the hue of water-soaked flesh, an unhealthy buff. It was a color worthy of these black depths, like the sickly sprouts of plants in a cellar. Another strange thing was its almost tailless condition, the caudal fin being reduced to a tiny knob or button, while the vertical fins, taking its place, rose high above and stretched far beneath the body, these fins also being colorless.”

Beebe assigned the pallid sailfish into the family Stomiidae, the same family that Bathysphaera intacta is assigned to as well as the other blackdragons. As a group, the fish in this family are called barbeled dragonfish. Some species in this family do show a similar tail arrangement that Beebe noted, with a very small tail fin but enlarged anal and dorsal fins that are set well back on the body. This includes a weird fish with various names, including black hinge-head, black loosejaw, or lightless loosejaw, which maybe gives you an idea of what it looks like. It’s a deep-sea fish like all the barbeled dragonfish, and it’s black in color. It grows about 10 inches long, or almost 26 cm. It’s also sometimes called the stoplight loosejaw because it has two photophores on its head, one of which shines green, the other which shines red. Unlike most deep-sea fish, it can see in the red spectrum, so the green photophore may attract prey and the red photophore allows the loosejaw to see its prey even though the prey can’t see the loosejaw. But mainly, it has remarkable jaws.

The loosejaw’s jaws are hinged and extremely large compared to the body, which is fairly thin. The jaws are so large that they’re not even attached to its body, just to its head. They aren’t even connected to the body with skin. It’s hard to describe, but I have some good pictures of a model of the fish in the show notes. Basically, the jaws are just bones covered with a thin layer of skin, but no skin or muscle in between the bones. If you put your thumb under your chin, you can feel your chin bone, then move your thumb backwards and instead of bone, you feel skin over layers of fat and muscle and other tissues that make up the soft part of your jaw. Well, the loosejaw doesn’t have those soft parts. It just has the chin bone and there’s literally nothing between the jaws. It doesn’t have a throat or cheeks or anything like that. Its jaws aren’t big because it needs to swallow big things, its jaws are big so it has a longer reach to snag the small fish and crustaceans it eats. It has a lot of needlelike teeth that it uses to keep its prey from wriggling away while it maneuvers it into its gullet. It mostly eats very small animals, but it’s not going to let anything get away once it gets within jaw range.

While I was researching this episode, I spent a ridiculous amount of time trying to find the episode where I talked about the umbrellafish, thinking it might be related to the loosejaw. It’s not, and I finally realized the umbrellafish episode was for patrons. I’ve unlocked that Patreon episode and linked to it in the show notes if you want to go listen to it. The umbrellafish, also called the gulper eel, looks superficially like the loosejaw, but it has skin over its huge hinged jaws.

After my inability to properly describe the loosejaw’s amazing jaws, let’s move on to Beebe’s other mystery fish. One he named the three-starred anglerfish, Bathyceratias trilychnus, which he estimated was about six inches long, or 15 cm. It had three bioluminescent illicia on its head that it probably used as lures, since that’s something that other deep-sea anglerfish do and Beebe was pretty sure it was actually a species of anglerfish. Since there are over 200 known species of anglerfish, it’s not surprising that there are more that aren’t known.

Another was the five-lined constellation fish, Bathysidus pentagrammus, named for the five rows of photophores on its sides. Beebe thought it looked kind of like a surgeonfish, which is a flat, round fish shaped sort of like a pancake with fins and a tail. But surgeonfish are mostly found in shallow, tropical waters around coral reefs. They’re often brightly colored. Beebe didn’t assign his constellation fish to the surgeonfish’s family, and in fact didn’t assign it to any family since he didn’t know where it belonged.

The last of Beebe’s mystery fish was the rainbow gar, which he didn’t give a scientific name to since he had no idea what kind of fish it might be. He thought it was shaped like a gar, but it was so extraordinary he didn’t know what to think. He actually saw four of them swimming almost vertically, heads up and tails down, at about 2,500 feet deep, or 760 m. He named them rainbow gar because of their coloring: bright red head and jaws, a light blue body, and a yellow tail. They were about four inches long, or a little over 10 cm, with long, pointed jaws. They moved by fanning the dorsal fin, sort of like a seahorse.

Beebe wrote scientific articles about some of these fish and included them all in his book Half Mile Down. But it wasn’t long before other scientists started doubting the sightings. Some people thought he’d made up the fish to make his expeditions more exciting, some thought he was just mistaken. One irate ichthyologist wrote in 1933 that the constellation fish was probably just light reflecting off Beebe’s own breath fogging the window, because no fish had photophores like the ones he described. Because I guess in 1933 everything was known about fish that would ever be known, right?

Beebe seems to have been an honest scientist, though, and he didn’t really need to make anything up. He discovered dozens, if not hundreds, of fish new to science, many of which have either been found and properly described later, or which Beebe himself managed to later catch. Whenever he and Barton came up from a descent in the bathysphere, Beebe had his team on the boat send down nets, and sometimes they caught some of the animals he had seen. This allowed Bostelmann to add details to her paintings that Beebe wouldn’t have known about from just a look through the bathysphere’s windows.

Not only that, if Beebe wanted to make up a fish that would excite the general public and make them want to buy his books, he would have made up something huge and frightening. His mystery fish are mostly quite small. Only Bathysphaera intacta was large, and he only said they were about six feet long. That’s big for a deep-sea fish, but remember that the bathysphere never made it to the really crushing depths of the abyss. It descended into the mesopelagic zone, which is extremely dark but not completely lightless. There’s also a lot of life in this zone, and many fish that spend the day here migrate nearer the surface at night where they can find more food while still remaining hidden. The long-snouted lancetfish lives in this zone and it can grow seven feet long, or 2.15 m.

Plus, Beebe didn’t need to convince anyone to buy his books. They were already runaway bestsellers and he was quite famous, although it seems not to have gone to his head. He just wanted to have fun and do science. He actually seems to have been a good person by modern standards too, which is always refreshing. He disagreed with people who claimed to have scientific proof that women were inferior to men or that some races were inferior to others. He insisted that his team members work hard, but he worked hard too, and if he thought everyone was feeling too stressed, he’d announce that his birthday was coming up and they should take a few days off to celebrate. Some years he had several birthdays.

Beebe did spot one other mystery animal, but he didn’t get a good enough view to make a guess as to what it might be. This is what he wrote about it:

“…I saw its complete, shadow-like contour as it passed through the farthest end of the beam [of light]. Twenty feet is the least possible estimate I can give to its full length, and it was deep in proportion. The whole fish was monochrome, and I could not see even an eye or a fin. For the majority of the ‘size-conscious’ human race this marine monster would, I suppose, be the supreme sight of the expedition. In shape it was a deep oval, it swam without evident effort, and it did not return. That is all I can contribute, and while its unusual size so excited me that for several hundred feet I kept keenly on the lookout for hints of the same or other large fish, I soon forgot it in the (very literal) light of smaller, but more distinct and interesting organisms.

“What this great creature was I cannot say. A first, and most reasonable guess would be a small whale or blackfish. …[O]r, less likely, it may have been a whale shark, which is known to reach a length of forty feet. Whatever it was, it appeared and vanished so unexpectedly and showed so dimly that it was quite unidentifiable except as a large, living creature.”

Twenty feet is six meters, by the way. It might easily have been a whale, since many species of whale routinely dive much farther than the bathysphere descended at its deepest. Whatever it was, and whatever Beebe’s other five mystery fish were, hopefully one day a modern deep-sea vehicle will find them again.

You can find Strange Animals Podcast online 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way. Don’t forget to enter our book giveaway if you haven’t already, too! Details are on the website.

Thanks for listening!