Tag Archives: dolphins

Episode 308: Rescuing Stranded Whales

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Yay, we’re at the end of the year and looking forward to 2023! Boo, I caught covid and I’m still recovering, so here’s a repurposed Patreon episode about whale strandings and how people help the whales!

A minke whale calf being transferred via rescue pontoon to a boat to tow her farther out to sea than the pontoon could manage for such a big whale (photo from this article, which explains that she rejoined her mother and swam away safely):

Pilot whales being rescued after stranding:

Show transcript:

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

It’s the last episode of 2022, and…I’ve got Covid. I’m fully vaccinated and fortunate enough to be a basically healthy person, so my symptoms were mostly quite mild and I’m feeling much better although I’m still quarantining. Because my voice isn’t really at 100% due to coughing, and because I haven’t had the energy to do any research, I decided to run an old Patreon episode this week. I always feel bad for my awesome patrons when I do this, but I really like this episode and it’s several years old now. It’s about mass whale strandings but I focused on how people help whales, so even though it’s a sad topic I hope you find it hopeful and interesting.

With the end of 2022, we also say goodbye to the birthday shout-outs since it was only for 2022. I hope I didn’t miss anyone. Let’s have one final birthday shout-out, though. This one’s for everyone! You’re having a birthday in 2023 so I hope it’s the best birthday you’ll have had so far!

Now, let’s learn about mass whale strandings.

[little intro sound to help hide the fact that the audio changes a whole lot here]

This is a sad phenomenon where whales swim onto shore and get beached, and if they don’t get help they die. A whale breathes air, sure, but it’s evolved to be in the water full-time. As soon as it’s on land, the weight of its own body starts to smother it and it also starts to overheat.

Sometimes just one or two whales strand themselves, sometimes it’s a whole pod. We’re still not completely sure of the causes except that there’s undoubtedly more than one cause. Navy sonar may play a part, disorienting and frightening whales, even deafening them. Water pollution, disturbances of the earth’s geomagnetic field, extreme weather, injuries, disease, the whales fleeing predators or pursuing prey, and all sorts of other issues may be causes or partial causes.

Most whales that strand themselves are toothed whales, which rely on echolocation to navigate. Many researchers think that some coastlines that slope very gently can confuse the whales, who think the seafloor is level when the water is actually getting shallower and shallower. Certain areas with gently sloping beaches have mass strandings of whales and dolphins almost every year.

Some species of whale are more prone to stranding than others, too, especially pilot whales, which are actually dolphins despite their name. The largest mass stranding known was of pilot whales, with over a thousand of them beached in 1918 on Chatham Island in New Zealand. Pilot whales can grow more than 23 feet long, or over 7 meters, and live throughout much of the world’s oceans. They mostly eat squid but will eat fish too, and sometimes dive deeply to find food.

Chatham Island is one of those areas where whales get stranded repeatedly, as are several other islands and bays around New Zealand. The coastal waters are shallow with a number of sandbars, and the whales apparently get disoriented and don’t realize they’re coming up onto the beach instead of just crossing another sandbar. Almost every summer some pilot whales become stranded, sometimes hundreds of them.

One species of whale that almost never gets stranded is the killer whale, or orca. Orcas frequently hunt seals, which flee onto land. Orcas learn how to navigate beaches, and will sometimes beach themselves on purpose while attempting to catch a seal, then wriggle back into the sea. But most whales never approach the shore that closely under ordinary circumstances so they never learn how to avoid getting stranded permanently.

When people find stranded whales, our first impulse is to help them. But whales are big and heavy, so much so that most of the time even a group of people can’t lift them. But humans are smart and social, and we’ve worked out a system to help stranded whales.

First, the whales need to be kept as cool as possible until more help arrives. People pour water over stranded whales to help cool them down, but make sure that their blowholes remain clear of sand and water so they can continue to breathe. Wet bed sheets draped over the whales help too, again making sure to keep the blowholes clear.

Next, as the tide comes in and the water rises around the whales, it’s important to help turn the whales onto their bellies. The whales usually can’t do it themselves, especially if they’ve been stranded for hours and are exhausted and having difficulty breathing. If they aren’t turned upright, they may drown as the water covers their blowholes before it’s deep enough to float the whales.

Sometimes, frustratingly, as soon as a stranded whale is floated out to sea so it can swim away, it will turn around and beach itself again. No one’s sure why. It may be responding to the same confusion or anomaly that caused it to strand itself in the first place, or it may be responding to the distress calls of other whales that are still stranded.

Rescuers have used the sociability of whales to help them too. In one case in New Zealand, in 1984, almost 150 pilot whales became stranded in Tryphena Harbour. As the tide rose, the helpers floated the whales out to sea—but so many of them returned to beach themselves again that when they floated a mother whale and her calf out to sea, the rescuers made sure to keep her in place. She and the baby called to the other whales, which made them come to her instead of return to the beach. 67 of the whales were saved and ultimately swam out to sea.

In 1991, 14 pilot whales stranded near Shipwreck Bay in New Zealand were rescued by truck. The surf was too dangerous to refloat them at the beaching site and something had to be done. 18 whales had already died. Hundreds of volunteers turned out to help, including local businesses who donated the use of trucks and other items. The whales were lifted by log-loader onto three big trucks, their beds lined with hay, and hay bales were used to keep the whales propped up during the ride. People rode with them to douse them with water too. The police escorted the trucks as they drove 90 minutes to the mouth of a river, where the whales were lowered into the water and floated out to sea.

Two of the whales promptly turned around and beached themselves again, but the volunteers had brought Rescue Pontoons designed to refloat beached whales. The two whales were brought back out to sea where they rejoined the rest of the rescued whales, which then swam off together.

The rescue pontoons were designed in 1984 by New Zealander Steve Whitehouse after he saw the damage ropes did to whales as rescuers tried to pull them back out to sea. They’re made up of inflatable cylinders with handles and quick release clips. After the first one was made it was tested by moving a huge concrete pipe filled with sandbags into the ocean and back repeatedly. It was first used to rescue a whale in 1986 when a Southern Bottlenose whale was stranded among rocks that would have kept it from being moved by ordinary means. But Steve and his team traveled to the whale, rolled it onto the pontoon and inflated it, then refloated it into the sea. The whale was saved and the rescue pontoon proved it could do the job it was designed for.

Since then, the rescue pontoon has saved hundreds, probably thousands, of whales and dolphins throughout the world. It’s also been used to rescue stranded manta rays, sunfish, and even grounded boats. So hooray for Steve and his rescue pontoon! Best invention ever.

Humans aren’t the only ones who want to help stranded whales. Sometimes other whales or dolphins help, usually local populations of dolphins who know the area well. In 2008 a New Zealand bottlenose dolphin named Moko, well-known to swimmers, helped a pair of pygmy sperm whales. The pair were a mother and calf, and every time they were refloated they would get disoriented and beach themselves again on a sandbar that blocked their way out of the harbor. Then Moko showed up.

One of the rescuers, Juanita Symes, said, “Moko just came flying through the water and pushed in between us and the whales. She got them to head toward the hill, where the channel is.” Moko escorted the whales all the way out to sea, where they successfully swam away.

[little outro sound]

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 for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 153: The White River Monster

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Let’s start out the new year with a bona fide mystery animal, the White River Monster from Arkansas! Is it a real animal? If so, is it a known animal or something new to science? If it’s a known animal, what could it be? Lots of questions, maybe a few answers! Happy new year!

Further listening:

MonsterTalk

The not exactly useful picture supposedly of the White River Monster, taken in 1971:

A northern elephant seal, AKA Mr. Blobby:

A Florida manatee:

A bull shark:

Two bottlenose dolphins:

An alligator gar (below) and a human (above):

Alligator gar WEIRD FISH FACE:

Gulf sturgeon:

Show transcript:

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

If you’ve listened to the final episode of 2019 last week, you’ll remember it was about some mystery water animals of various kinds. Well, I’ve got another water mystery for you today to start off the new year, the White River monster. I heard about this one in a recent episode of MonsterTalk, which is a great podcast I recommend if you don’t already listen to it.

The White River is in North America, originating in the mountains in northwestern Arkansas and flowing from there through Missouri, then back into Arkansas where it joins the Mississippi River. In 1915 a man near the small town of Newport, in the central Ozarks region of Arkansas, saw an enormous animal with gray skin in the river.

A few other people saw it too, but it wasn’t until July of 1937 that things really heated up. The monster returned, and this time a lot of people saw it. News of it hit the local papers and spread throughout the country, and people started showing up to look for it. Some people came prepared to kill or catch it while others just wanted to see it.

Estimates of the monster’s size varied quite a bit. A man named Bramlett Bateman, who owned a lot of the farmland along that stretch of the river, was quoted in several newspaper articles. He described the monster as being the length of three cars in one article, but in another his estimate was smaller, only 12 feet long, or 3.7 m, and four or five feet wide, or 1.2 to 1.5 meters. But it doesn’t seem that he or anyone else got a really good look at it.

It was described by numerous people as being gray-skinned. Bateman said it had “the skin of an elephant…with the face of a catfish.” I dug into as many original newspaper articles as I could find without actually paying for access to them, and very few of them have a real description of the animal. The only description given in a New York Times article from July 23, 1937 is this:

“Half a dozen eye-witnesses…reported seeing a great creature rise to the surface at rare intervals, float silently for a few minutes and then submerge, making its presence known only by occasional snorts that bubbled up from the bottom.”

Another article quotes Bateman as saying he saw the monster “lolling on the surface of the water.”

Bateman decided he was going to blow the monster up with dynamite. What is it about people whose go-to solution to seeing an unidentified animal is to throw dynamite in the water? The local authorities said, uh no, you cannot just throw dynamite into the river, but other people brought machine guns and other weapons and patrolled the river looking for the monster. A plan to make a giant net and catch the monster petered out when people found out that making and deploying a net that big is expensive and difficult.

The monster was mostly reported in an eddy of the river that stretched for about a mile and was unusually deep, about 60 feet deep, or 18 meters. The river is about 75 feet wide at that point, or 23 meters. The Newport Chamber of Commerce hired a diver from Memphis named Charles B. Brown, who brought an eight-foot harpoon with him when he descended into the river. He didn’t find anything, but the tourists had fun.

Suggestions as to what the monster might be ranged from a sunken boat that sometimes bobbed briefly to the surface to a monstrous catfish. Many people were convinced it was a huge fish of some kind, especially an alligator gar.

Eventually sightings tapered off and the excitement died down until June of 1971, when it started being seen again. Again the size estimates were all over the place, with one witness saying it was the size of a boxcar, which would be about 50 feet long, or 15 meters, and 9 feet wide, or 2.8 meters. Another witness said it was only 20 feet long, or 6 meters. Some witnesses said it had smooth skin that looked like it was peeling all over, had a bone sticking out of its forehead, and it made sounds that one witness described as similar to both a horse’s neigh and a cow’s moo. On July 5, 1971, three-toed tracks 14 inches long, or 36 cm, were also found on an island together with crushed plants that showed a huge animal had come out of the water.

This time, at least, no one tried to dynamite or even net the monster. Instead, in 1973 Arkansas passed a law creating the White River Monster Refuge along that section of the river, to protect the monster. But no one has seen it since.

There is a photo of the monster taken in 1971, but it’s a blurry Polaroid that was reproduced in a newspaper and the original lost. The photo was taken by a man named Cloyce Warren, who was out fishing with two friends. Warren said it had “a spiny ridged backbone and [was] splashing all around.”

So what could the White River Monster be? Is it a misidentified known animal, a completely unknown animal, or just a hoax?

Obviously people are seeing something in that part of the White River. But it’s reportedly so big that if there was a population living anywhere in the river, it would be spotted all the time. So maybe it’s an animal that only sometimes strays into the White River and actually lives in the much larger Mississippi River—or even in the Gulf of Mexico, where it sometimes swims upriver.

Cryptozoologists and other interested people have made suggestions over the years. One suggestion is that it’s an elephant seal. The northern elephant seal is an enormous animal, although it’s nowhere near 50 feet long. The male is much larger than the female, up to 16 feet long, or 4.8 meters, and bulky with blubber that keeps it warm when diving deeply for food in the Pacific Ocean where it lives.

But wait, the Pacific Ocean? You mean it doesn’t live in the Gulf of Mexico?

Nope, the endangered elephant seal only lives in the Pacific. And the Pacific Ocean is separated from the Gulf of Mexico by a whole lot of the North American continent.

A man named Joe Nickell, who’s a paranormal investigator and who was interviewed on MonsterTalk episode 204, has suggested the White River Monster is a manatee—specifically the Florida manatee, which is a subspecies of West Indian manatee. In the winter it mostly lives around Florida but in summer many individuals travel widely. It’s sometimes found as far north as Massachusetts along the Atlantic coast, and as far west as Texas in the Gulf of Mexico.

The manatee is large, up to 15 feet long, or 4.6 meters, with females being somewhat larger than males. Its skin is gray but since it moves slowly, it can look mottled in color due to algae growing on its skin, and it sometimes also has barnacles stuck to it the way some whales do. It has a pair of front flippers with three or four toenails, no hind legs, and a paddle-like tail. It eats plants and only plants, and is completely harmless to humans, fish, and other animals. Also because it moves slowly and spends a lot of time at the surface, since it’s a mammal and has to breathe air, it’s vulnerable to being injured by boats.

In the 1970s there were only a few hundred manatees alive and it nearly went extinct. It was listed as an endangered species and after a lot of effort by a lot of different conservation groups, it’s now only considered threatened. So while people might recognize a manatee these days, back in the 1970s it was practically unknown everywhere except southern Florida since it was so rare. And in the decades before 1971, people didn’t travel as much and didn’t know much about increasingly rare animals that didn’t live in their particular part of the world.

In other words, it’s completely possible that people from Arkansas would see a manatee in 1915, 1937, and 1971 and not know what it was. But could a manatee really travel that far from the ocean and survive?

The Mississippi River empties into the Gulf of Mexico in Louisiana in the United States. Texas is to the west of Louisiana, then Mississippi, Alabama, and Florida to the east. In other words, it’s well within the known range of the Florida manatee. Manatees are known to sometimes travel up the Mississippi. This happened most recently in October of 2016 when a manatee traveled as far as Memphis, Tennessee before it was found dead in a small lake connected to the river. That’s a distance of 720 miles, or 1,158 km, and that was with wildlife officials trying to capture it to return it to the Gulf. That same year a manatee also traveled as far as Rhode Island along the Atlantic coast. Memphis is actually much farther up the Mississippi than the White River is, so if the manatee had branched off into the White River it might have led to new sightings of the White River Monster.

The manatee can live in fresh water perfectly well. One species, the Amazonian manatee, is a fully freshwater animal that never leaves the South American rivers where it lives. But despite its size, the manatee doesn’t have a lot of blubber or fat to keep it warm. The farther away it travels from warm water, the more likely it is to die of cold.

But while an errant manatee might explain some White River Monster sightings, it doesn’t fit with all of them. Other animals from the Gulf of Mexico sometimes find their way up the Mississippi too. It’s a huge river, and since an ocean animal doesn’t understand what a river is, it doesn’t know it’s never going to reach the ocean again unless it turns around. Most marine animals can’t survive for long in fresh water, but some animals, like the manatee, can tolerate fresh water much better. That’s also the case for the bull shark.

In 1937, the same year the White River Monster was spotted for the second time, a five-foot bull shark, or 1.5 meters, was caught in Illinois, which is even farther upstream from the Gulf of Mexico than Tennessee and Arkansas. Bull sharks live throughout much of the world’s oceans in warmer water near coasts and are often found in rivers and lakes, although they don’t live as long in fresh water as they do in salt water. The largest bull shark ever measured was 13 feet long, or 4 meters, so a large one is about the size of a manatee.

Occasionally a dolphin travels up the Mississippi River, but marine dolphins can’t survive for long in fresh water and will die soon if they can’t make their way back to the ocean. A dolphin in fresh water starts to develop skin lesions and then the skin begins to peel, leading to bacterial infection and death. Remember that some witnesses in 1971 described the White River Monster as a gray animal with peeling skin.

Nine different species of dolphin and many species of whale live in the Gulf of Mexico. Of those, only the bottlenose dolphin lives close to the coast and is usually the species that accidentally travels into fresh water and can’t find its way out. The bottlenose dolphin isn’t any larger than the manatee, up to about 13 feet long, or 4 meters.

1971 was an active hurricane year, including the category 5 Hurricane Edith that killed 37 people in mid-September. Marine animals that can travel quickly, like dolphins and sharks, will flee to calmer waters when a hurricane approaches, and while that usually means out to sea, it wouldn’t be out of the question for a frightened dolphin or other large marine animal to make its way into the Mississippi by accident ahead of a hurricane, especially a hurricane as big as Edith.

Another possible identity for the White River Monster is one that was suggested in 1937, the alligator gar. It’s a freshwater fish that lives throughout the Mississippi River and other rivers and lakes in the southern United States and parts of northern Mexico. The alligator gar gets its name because of its toothy jaws, which do resemble an alligator’s, and it can grow up to ten feet long, or 3 meters. It’s a really weird fish and eventually I’ll probably do a full episode on it and its relatives, just as I have a full episode planned about the manatee. It has gills like other fish, but it can also breathe air through its swim bladder, which is lined with lots of blood vessels that absorb oxygen. Every so often an alligator gar will come to the surface and gulp air to replenish the oxygen in its swim bladder, so it would be seen at the surface briefly but periodically as was described by many witnesses. This is also the case for the manatee and dolphin, who breathe air.

The alligator gar is an ambush predator, which means it waits in the water without moving much at all until an animal approaches. Then it shoots forward and grabs it. It mostly eats small fish, invertebrates of various kinds, and waterfowl like ducks.

The final possibility of the White River Monster’s identity is the gulf sturgeon. It’s a subspecies of the Atlantic sturgeon that lives in the Gulf of Mexico, although it’s also known from various rivers in the southeastern United States. The reason it’s found in rivers is that the gulf sturgeon is anadromous [a-NADro-mus], the term for a fish that migrates from the ocean into fresh water to spawn. The salmon is the most famous anadromous fish, which fights its way upriver to spawn and then die. In the case of the gulf sturgeon, it hatches in fresh water and lives there for the first two years or so of its life before making its way downstream to the ocean. Then it returns to freshwater to spawn every spring, usually the same river where it was hatched, and goes back to the ocean in autumn.

The gulf sturgeon fits a lot of the descriptions of the White River Monster sightings. It’s covered with five rows of scutes that project from the back and sides in a sort of low sawtooth pattern, which fits the “spiny ridged backbone” that Cloyce Warren reported seeing in 1971, and its elongated snout has sensory barbels like a catfish, which matches Bramlett Bateman’s 1937 description of the monster having the face of a catfish. It’s gray, gray-green, or brownish in color with a lighter belly, and it can grow up to 15 feet long, or 4.5 meters, although most are about half that length.

The gulf sturgeon usually migrates in groups, but occasionally one can get separated from its group and find its way into a stretch of water by itself. It also doesn’t eat much during the summer when it’s in freshwater. In the winter it lives just off the coast in shallow water, where it’s a bottom feeder. It sucks up invertebrates from the sea floor, feeling for them with their barbels. It gains lots of weight during the winter and then loses it all in the summer. Sturgeons do sometimes jump out of the water, especially in summer–as much as fix feet out of the water. No one’s sure why. Also during the summer, the sturgeon makes a sound like a creaky hinge.

I think it’s probable that the White River Monster sightings are of more than one type of animal, and while we can make an educated guess as to which animals might have been spotted and misidentified, we can’t know for sure. So while at least some of the sightings may have been of a manatee or a gulf sturgeon or another of the animals we talked about today, there’s also the possibility that something else occasionally swims up the Mississippi from the Gulf and into the White River. Hopefully, next time the White River Monster appears, someone gets a really good look at it and some good pictures so we know for sure.

This is what a sturgeon sounds like, by the way:

[sturgeon creaky sound]

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. We also have a Patreon if you’d like to support us and get twice-monthly bonus episodes.

Thanks for listening!

Episode 098: River Dolphins

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This week let’s learn about some unusual cetaceans, river dolphins!

An Amazon river dolphin and the nose of another Amazon river dolphin:

Another Amazon river dolphin. Note the teeny eye and disk-like teeth:

A South Asian river dolphin. Note the almost nonexistent eye:

A Chinese river dolphin in better days:

Show transcript:

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

This week we’re going to learn about an animal I’ve wanted to cover for a long time but never got around to, the river dolphin.

All whales and almost all dolphins live in the ocean. They can survive for a short while in fresh water but need saltwater to thrive. But as the name suggests, the river dolphin lives in rivers, usually in fresh water and sometimes in the brackish water where rivers empty into oceans. Brackish just means a mixture of fresh and salt water, so it’s saltier than fresh water but not as salty as ocean water. When I was a kid I thought it meant ocean water with a lot of seeweed and dead leaves in it, because I thought the word brackish had something to do with bracken, which is a type of fern.

There are only a few species of river dolphin alive today. They live in warm water and have very little blubber as a result. They primarily use echolocation to navigate since river water tends to be muddy and hard to see through. Their flippers are broad and most have long snouts and flexible necks, or at least flexible compared to other cetaceans. All river dolphins are endangered due to pollution, habitat loss, and accidental drowning in fish nets, with the Chinese river dolphin only having been declared extinct in 2006.

River dolphins evolved from dolphins that once lived in the ocean, but most aren’t closely related to the marine dolphins alive today. Researchers think that when modern dolphins and other toothed whales evolved, they outcompeted their more primitive cousins, who moved into freshwater habitats as a result.

A few years ago, fossils of an extinct river dolphin that grew more than nine feet long, or almost three meters, were found in Panama. It lived around 6 million years ago in the Amazon River, but researchers don’t think modern river dolphins are closely related to it. In other words, freshwater dolphins have evolved repeatedly in different parts of the world to fit an available ecological niche.

In the case of the newly discovered fossil river dolphin, Isthminia panamensis, it probably lived in the warm, shallow Caribbean Sea between North and South America before the Isthmus of Panama formed. It took millions of years for the isthmus to form, with undersea volcanos first emerging from the ocean around 15 million years ago to form islands, then the land itself being pushed upward as the Pacific Plate slid underneath the Caribbean Plate. Researchers think the isthmus became fully formed around 3 million years ago, separating the Atlantic Ocean from the Pacific and connecting North and South America. Because we have Isthminia panamensis’s fossil from the Amazon River, we can hypothesize that by around 6 million years ago, there wasn’t enough of the original Caribbean Sea habitat to support the dolphins and they had already moved into the Amazon River and adapted to life in freshwater.

The river dolphin isn’t the only cetacean that lives in freshwater. There’s a species of porpoise called the finless porpoise that lives around Asia in shallow coastal waters, but often spends at least part of the time in mangrove swamps and in rivers not too far from the sea. Porpoises and dolphins look very similar but belong to different families, which means they aren’t actually very closely related at all. Like, seriously not related at all. Like, the difference between horses and cows. The finless porpoise can grow almost seven and a half feet long, or over two meters, and is called finless because it doesn’t have a dorsal fin. Instead, it has a dorsal ridge lined with tubercles, or bumps, that contain nerve endings. Researchers don’t know what purpose the tubercles serve. Porpoises use echolocation but their clicks are much higher in frequency than dolphins’, so high that humans can’t hear most of them.

There are three families of river dolphins still living today, Platanistidae, Iniidae, and Pontoporiidae.

Platanistidae are the Indian dolphins, with only one species alive today. The South Asian river dolphin lives in South Asia. There are two subspecies, the Ganges River dolphin and the Indus River dolphin. Young South Asian river dolphins have sharp, thin teeth, but as the dolphin matures, its teeth become flatter and squarish, almost like disks. It eats fish, crustaceans like shrimp, and some dolphins may also eat water birds and even turtles. Its rostrum, the word for a cetacean’s beak, is considerably longer in females than in males, sometimes like 8 inches longer, or about 20 cm.

The South Asian river dolphin is sometimes called the blind dolphin because its eyes are basically only useful for sensing light. They don’t even have lenses. It has a very small dorsal fin, not much more than a bump, a powerful tail, and is brown in color, and grows up to ten feet long, or almost 3 meters. It uses echolocation to navigate in the murky river water and find prey. It also usually swims on its side, which also gives it the name side-swimming dolphin. It does this so it can trail the tip of a flipper along the river bottom to feel for shrimp and mollusks.

It’s such an unusual dolphin, even for river dolphins, that researchers are studying fossil dolphins to figure out how the South Asian river dolphin evolved. Two years ago, a fossilized dolphin skull found in 1951 in Alaska and held in the Smithsonian’s collection ever since was evaluated and determined to be a distant relative of the South Asian river dolphin. It lived about 25 million years ago, around the time that ancient whales were evolving into the two groups we have today, toothed whales, which includes dolphins, and baleen whales.

The South Asian river dolphin has been evolving separately from marine dolphins for at least the 25 million years since its relative was swimming around in the Arctic Ocean. Research on its echolocation suggests that the Ganges River subspecies of the South Asian river dolphin probably has biosonar that more closely resembles that of ancient toothed whales than modern toothed whale and dolphin echolocation does. It has a much deeper voice than marine dolphins of about the same size have.

I tried very hard to find a recording of a Ganges River dolphin, or any South Asian river dolphin, but all I found was this, the echolocation of an Amazon river dolphin:

[river dolphin sound]

The Amazon river dolphin is a member of the Iniidae family of river dolphins. It’s the biggest of the river dolphins, and adults are often pink in color. In all other river dolphins, and most cetaceans in general, females are larger than males, but male Amazon river dolphins are larger than females. Babies are dark gray, fading to lighter gray as they grow up. Adults can appear pink because the skin is often pale and in warm water, the blood shows through the skin. The Amazon river dolphin has small eyes, but it sees a lot better than the South Asian river dolphin.

Most river dolphin species aren’t nearly as sociable as marine dolphins and are usually only found singly or in groups of two or three. Male Amazon river dolphins often fight each other when females are around. If a male Amazon river dolphin meets some females, he will pick up a branch or stone and carry it around to impress them.

Amazon river dolphins eat fish, including piranhas, freshwater crabs, turtles, and other small animals. Sometimes a dolphin will participate in cooperative hunting with giant otters and the tucuxi, another species of dolphin that lives in the Amazon basin. The three species eat different types of fish so they all benefit from hunting together.

The tucuxi isn’t actually a river dolphin although at least some individuals live in rivers. It’s considered a marine dolphin, and you can tell the difference just by looking at it. It looks like a small bottlenose dolphin, about five feet long, or 1.5 meters, and unlike river dolphins its rostrum is relatively short.

The third family of river dolphin is Pontoporiidae, and there’s only one species alive today. Just to show that nature isn’t cut and dried, the La Plata dolphin doesn’t always live in fresh water. It lives around the coast of southeastern South America and while some do spend their whole lives in rivers, most La Plata dolphins live in the ocean.

Finally, let’s talk about the Chinese river dolphin, the one that’s recently extinct, also called the baiji. Technically it’s functionally extinct because although there may be one or two still alive, there aren’t enough to continue the species into another generation. River dolphins do very poorly in captivity, usually dying within months, so even if conservationists had billions of dollars and the cooperation of every single person on earth to save the Chinese river dolphin, there’s nothing they could do at this point. In fact, in 2006 a research team searched for the dolphin for six weeks to put a conservation action plan into place for it, but they didn’t find any. That’s when it was declared extinct.

The Chinese river dolphin lived in the Yangtze River and grew up to 8 feet long, or 2.4 meters. It was blue-gray with a paler belly, and like many other river dolphins, its rostrum was slightly upturned. It also had poor vision. It was once common along much of the Yangtze, some 1,100 miles of river, or 1,700 km, but massive increases in pollution of the river, collisions with boats caused by the noise of boats overwhelming the dolphins’ echolocation, poaching, entanglement in fishing nets, loss of habitat due to damming of the river, and overfishing drove it to extinction within about five decades. The last confirmed sighting of a Chinese river dolphin was in 2002, with an unconfirmed sighting in 2007.

This is a depressing way to end the episode, so let’s finish up with a long-ago relative of the South Asian river dolphin. Zarhachis flagellator lived during the Miocene, about 16 million years ago, and had a really long rostrum. Like, super super long. Its skull was about four feet long, or 1.2 meters, which makes it sound like it must have been a really big dolphin, but it wasn’t. Its actual braincase was less than a foot long, maybe 8 inches or so, or 20 cm. The rest of the length was rostrum. In other words, it had a head about the size of your head, and a long thin beak full of sharp teeth that was something like three feet long, or almost a meter. Tonight when you brush your teeth, think about that. Think about how hard it would be to reach all your teeth if you had a mouth that stuck out three feet from your head. You’d need a really long toothbrush.

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