The Monongahela River, or “the Mon”, is a 130 mile long waterway that cuts through Pennsylvania and West Virginia, connecting Pittsburgh to Fairmont. As many Appalachian places, it is a hotspot for cryptid activity. Flowing into the Ohio River, perhaps it has been the culprit all along–the origin of all the strange and scary in, what must be, one of the country’s most haunted waterways. Or, at least, some of its evil’s origins. While the Ohio River has a plethora of mysteries that span across every monster category, the Mon only has a handful; but, the ones it does have are weird and unique. Inside its waters hide humanoid fish, two-headed, giant turtles, and incredibly long, mega-catfishes. On its banks wander electric bigfoot, super smart bigfoot, handsome bigfoot, and little bigfoot. My favorite is the most obscure of them all: a giant, man-eating beaver.

Now, when I first came across a mention of this creature, I thought, “hold on, this can’t be real.” While I feel that way about almost all cryptids, I meant it in a different way for the Monongahela Giant, Man-Eating Beaver. In all of my research, chats, and reading, I had never heard of it. And this is something people would talk about, right? It was in a news article, listed among several popular West Virginia cryptids you expect to see in every list. Snarly Yow. Mothman. Flatwoods Monster. Then, it began talking specifically about those sighted in or around the river. Ogua, Monongy. Nestled between was two sentences, a blip among paragraphs about much more lore-rich creatures, almost a footnote. I wrote every detail down, jotted down the source, and went on a hunt for more about it. But, there was no more to be found. I couldn’t find anyone else who had heard of the thing at all. I suspect that the addition was an author insert, a hoax, or maybe something someone got tricked into believing was a real cryptid. But there’s always that chance that it’s just that obscure, nearly forgotten. 

That was sometime between 2017 and 2019. I have yet to find any more information on the Giant, Man-Eating Beaver (or Fangmalia, as I’ve begun calling it, for it reminds me of a silly, over-the-top, animal-Dracula, some kind of fearsome critter). What’s most baffling for me is that the source I discovered it in no longer exists. Well, it does exist, but it has definitely been modified since then. It no longer is a simple posting of black text on white background, like a Notepad screen copied and pasted with bold, default text titles and little else. It has been modernized, beautified. Part of me takes this as a validation that it was purposefully added, a hoax creature. Another part of me wonders if I wrote the source material down wrong, and now I’ll never be able to recover it. Regardless, those two sentences I read are gone. But, I still have the descriptions of it, so I want to talk about it anyway.

Fangmalia isn’t particularly different from the usual North American beaver, appearance-wise. It has reddish-brown fur, little, dark round eyes, two clawed hands, webbed feet, and a paddle-tail. They are, however, more than double the size of a normal beaver, and their big, curved, rodent teeth are so large that they can’t close their mouths. They are much more aggressive, too, fighting anything and everything that accidentally invades their territory. When they become angry, they let forth a high-pitched whistle before charging, headbutting, and biting a victim. The whistle, apparently, sounds a lot like a steam train’s. It is a devastation to woodlands, leaving behind barren, bald spots, gnawed stumps and trampled plants; their activity gives off a similar, larger-than-life feeling associated with crop circles and meteor impacts, despite being, well, a big, albeit monstrous beaver. Lastly, as all beavers do, they build dams and lodges. Fangmalia’s are, of course, much larger, flooding towns and causing havoc.

If the Giant, Man-Eating Beaver is a thing at all, it is more of a legend than a cryptid, a vague lake and river monster. I couldn’t find any stories or serious witness accounts of it, or generalized giant beavers, even though this is a phenomenon that people seem to truly believe in. But, to be fair, sightings of larger than normal or giant animals are a pretty common, weird thing. Usually, they can be attributed to poorly estimating the size of something at a distance, being surprised at how large the animal is in real life, as well as lacking a frame of reference to judge it by. I did come across one book which claimed to have more information, in addition to actual eye witness accounts of giant beavers, linking them to strange, large tunnels, holes, and the fur trade in Manitoba. It was called "Strange Creatures Seldom Seen”, written by John Warms. I haven’t gotten a chance to read it, though, as the book runs from $50 to over $160, and my public library doesn’t have it, nor does Libby, and that’s a bit too steep a price for me. Maybe one day, if I come across it and feel like splurging, I’ll see what it has to say and maybe revisit this topic. 

Big animals on one hand, giant beavers also coincide with another popular cryptozoology topic: extinct animals that might not actually be extinct. In the late Pleistocene, there were giant beavers. We have discovered lots of their fossils; scientists have separated North American finds into two species: those that lived in the southeastern US were named Castoroides dilophidus, and those that roamed elsewhere, throughout North America, C. ohioensis. These beavers were big. On average, they grew to be about 6 ft tall, but some fossils reached over 7 ft in length. There is a bit of a dispute on how much they could weigh, some estimating a whopping 276 lb, while others conservatively put it closer to 170 lbs. They had shorter hind legs, longer, less padddle-like tails, wider hind feet, and more prominent teeth, which grew to be about 6 inches. We don’t know if they built dams and lodges, or if their feet were also webbed, but there is evidence that they spent a lot of time underwater. The animals’ skull structure hints that they could take in more oxygen, allowing them to hold their breath longer, and data also suggests that they ate aquatic, rather than woody, plants. One of the other major distinctions between North American beavers and these giant, older ones were their teeth; they didn’t just vary in size, but shape and texture. Beavers we see today have teeth with smooth enamel surfaces; these Pleistocene beavers had odd, striated ones. Aside from overall size, all of these traits might be easily overlooked by someone in the modern era, spotting one in a random river or lake. Going extinct alongside other North American mega fauna in the Pleistocene-Holocene transition, it is just incredibly unlikely that surviving members are still out there, wandering and splashing around. Wetland animals, ones that were doing pretty well a few hundred years ago, find themselves at risk of extinction in the present day, nevertheless 11,000 years ago. While we probably aren’t passing by ancient beavers, there was a time where people and giant beavers might have rubbed shoulders.

In Ridge Township in Wyandot County, Ohio, there is an archaeological site in a place called Sheriden Cave. Containing artifacts and remains from the late Ice age, the cavern was sealed off from the outside world by a glacier deposit more than 10,000 years ago. Stone and bone tools dating between 11 and 12,000 years ago were found inside, including rare finds, like bone spear points, flint hide scrapers, fluted spear points, and items from the Clovis culture. Scattered alongside these amazing finds were also human feces, gourds, wood charcoal, and the bones of Late Pleistocene animals–the giant short-faced bear, flat-headed peccary, stag moose, and our giant beaver. With a few places like this in existence, some believe humans may be a contributing factor to the giant beaver’s extinction, hunting them unsustainably so, but the changing climate, morphing wetlands probably hurt them just as badly, if not more so. A dent in the human-caused extinction theory, we have never discovered evidence that humans butchered, hunted, or utilized the animals, finding no wounds on the animals’ remains. Even if people didn’t eat or use giant beavers, they may have seen them.

The fossil record indicates that the last surviving members of the species hung on below the Great Lakes, in the lowlands of Ohio and New York, where native peoples were living at the time. Some First Nations cultures have a giant beaver in their myths. There is an Algonquin story about a giant beaver that built a dam so high that the resulting lake almost reached the sea. The dam was soon destroyed by a great figure, named Glooscap and his axe, creating a series of rapids found on the modern-day Saint John River, called the Reversing Falls. Glooscap chased the creature upstream, creating several islands as he tried to hit it; the animal evaded, swimming under the ice. It built another dam, creating the Great Lakes, but fled afterwards, not to be seen again. Another First Nation’s tale features a giant beaver that stood as tall as the tallest man and walked upright. While these stories don’t prove people and giant beavers shared territory, blows, or a stream, some claim that it could be evidence of First Nation contact with the extinct animals, or perhaps, at least, their bones.

Even if Fangmalia ends up being just a hoax... what if they were real? What would they be like? What if everything said about them was true?

I'm Ballyraven, your cryptid guide. Today, we're going to imagine what it would be like to stumble upon the Monongahela Giant, Man-Eating Beaver. For this encounter, we’ll be traveling by kayak, so grab your life jackets and paddles.

Paddling down the river, in the remote, Appalachian wilderness, it is a beautiful summer afternoon filled with birdsong and sunshine. The day after a rain, the river is a bit faster and fuller than normal, cloudy with green-brown sediment and debris. 

In the distance, something catches your eye. A tree moving, but alone, not in a group wave made by the wind. Staring ahead, you begin to think that it was a trick of the light, but then it happens again, more clearly: a small tree a little inland is shaking violently back and forth, as if something is pushing it. With an audible crack, you see the tree fall and hear its thud. You imagine it must be a park ranger and think no more of it.

Paddling further, you’re directly across from the felled tree. You drift in the center of the river, taking a break and peering into the woods curiously.The area is much more sparse than the surrounding forest; from here, you can pick out a wide, mostly cleared trail heading uphill. There are still several trees on the bank, blocking whatever was developing deeper in from view. A stack of logs are oddly piled high on the river’s edge.

Picking up your paddle, you start to move on before a sound grabs your attention again. It sounds like snapping twigs, something being dragged. Squinting, you see a dark shape pulling the tree towards the water. It is about as tall as a human, but thicker, hairier–and it has a tail. It pulls and pushes it next to the stack of logs, chewing on the remaining limb, breaking it off.

Suddenly, to your other side, you hear a loud whistle. Another giant beaver is on the opposing river bank. It stretches, looking at you, standing up on two large feet. It throws its head back, whistling again; shiny brown teeth glint in the sunlight. Its eyes almost seem to glow a red color. It rushes into the water, swimming towards you; the other animal begins to whistle, stomping its feet agitatedly. The creature is fast; its big, furry head bobs up and down in the water, but only the upper half of its face and neck are visible. 

You paddle as fast as you can, thankful the river isn’t fighting against you. Both are after you–and they are much faster. You can hear splashing behind you and feel one of them bump into your boat. Your arms are tired, but you keep pushing forward as hard, as fast as you can. You might not be able to outrun them…

A loud smacking sound, and another, and another. You’re too afraid to look back just yet. You wonder if that was their tail hitting the water in frustration. You see a bridge in the distance. You hazard a look behind you. Nothing. You don’t stop, paddling despite your exhaustion. You fling yourself, your boat onto the shore, pulling it just high enough on the bank so that it wouldn’t get swept back into the water. Then, you run. Climbing up the rocky, thorny hillside, you make it to the road, sprinting to the bridge. Looking down, there is nothing in the water–at least that you can see. You don’t want to risk it. You won’t be paddling back up the river. You’ll have to catch a ride instead.

Sources

“North American beaver.” Wikipedia, 11 Feb. 2019. Accessed 18 Feb. 2019.

Ellis, Rachel. “The Monsters of Marion County.” Marion County CVB, 16 June, 2016. Accessed 18 Feb. 2019.

Wikipedia Contributors. “Sheriden Cave.” Wikipedia, Wikimedia Foundation, 4 May 2025.

to, Contributors. “Giant Beaver.” Encyclopaedia of Cryptozoology, Fandom, Inc., 2026, cryptidarchives.fandom.com/wiki/Giant_beaver. Accessed 25 May 2026.

Warms, John. Strange Creatures Seldom Seen. 30 Apr. 2015.

‌“Mississaugas.” Wikipedia, 14 Aug. 2022, en.wikipedia.org/wiki/Mississaugas.

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Wikipedia Contributors. “Algonquin People.” Wikipedia, Wikimedia Foundation, 14 Mar. 2019, en.wikipedia.org/wiki/Algonquin_people.

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‌“Glooscap.” Wikipedia, 4 Mar. 2021, en.wikipedia.org/wiki/Glooscap.

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‌Wikipedia Contributors. “Anishinaabe.” Wikipedia, Wikimedia Foundation, 11 Oct. 2019, en.wikipedia.org/wiki/Anishinaabe.

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Wikipedia Contributors. “Castoroides.” Wikipedia, Wikimedia Foundation, 28 Jan. 2026.