Mar 11, 2023 I Brent Swancer

The Strange Case of a Lake Monster in the Jungles of Patagonia

There seem to be many mysteries of the unexplained that come to us from the uncharted, remote jungles of our world. It seems fitting, as these are places that exist on the periphery of our understanding, liminal, mysterious places that most;ly exist in their own world far from civilization. From jungles have come all manner of tales of mysterious beasts and oddities, and one of these is a little-known case of a large aquatic cryptid lurking within a remote and secluded lake on the edges of the world as we know it. 

In 1922, an American hunter and gold prospector by the name of Martin Sheffield came forth with a very bizarre story from the uncharted depths of the Patagonian jungle. In a letter to the Buenos Aires Zoo Director, Clemente Onelli, he claimed that in a remote lake in the shadow of Mount Pirque called the Laguna Negra there lurked a very large, bizarre creature with “head like a swan” that seemed to be amphibious, as it was sighted in the water and had also left tracks on the shore. He would say in his letter:

Allow me to bring to your attention the following phenomenon that surely will awaken your vivid interest because it deals with the possible entry to your zoo of an animal until now ignored by the world. I will narrate the facts: For some nights now, I have been noticing some tracks in the grass close to the lake where I have set up my hunting lodge; the track is similar to the foot print of a very heavy foot, the grass remains squashed and does not rise again which leads me to believe that the animal that dragged itself through there must have an enormous weight; I have been able to see, in the middle of the lake, an enormous animal with a head like a swan and enormous size and the movement in the water makes me suppose a crocodile body.

Argentina jungle

Sheffield went on to describe how he believed the creature could be hunted and a specimen preserved for study, and even detailed the necessary equipment for such an endeavor, including harpoons, boat and embalming materials. Onelli actually personally knew Sheffeld from his days as a member of the Argentine-Chilean Border Commission, and knew him to be a trustworthy explorer not prone to making up tall tales, and so his interest was definitely piqued. He was so excited, in fact, that he went about organizing an expedition to look for the beast, thinking that it was perhaps a new species or a previously thought to be extinct one, possibly a plesiosaur or even a type of extinct giant ground called a megatherium. When he went public with his intentions to launch a monster hunting expedition, the media made a lot of sensational headlines, and so Onelli made sure to mask the true location of the lake in order to avoid other would-be monster hunters from going there and disrupting his own efforts to find it. In the meantime, he spent a lot of time pondering the alleged creature’s habitat, and he wondered if Sheffield’s monster was the same thing as what was mentioned in various lore from the natives of the region describing similar beasts. Onelli would say:

For the last thirty years we have heard about it, only in those parts of our territory that were once claimed by Chile, on the oriental side of the divortiuim aquarum. From 1890 to the present time there had been twelve places in Patagonia, between latitudes 38 and 52, at which mysterious creatures had been reported. The animal’s legend is found only in the valleys on the west of this easily surpassable line of continental waters’ divide before transposing the, for it, insurmountable line of the real cordilllera. These are the only regions where a great edentate, an animal of the lowlands, could be because these forested and crooked valleys were never visited by the natives of southern Argentina. The current habitat should be the relatively low regions, not higher than 800 m [2,624 ft.] and very likely in the forests’ clearings and not in the thick woods, because the southern forest does not allow life under it.

As media attention grew, Onelli increasingly referred to the creature as a plesiosaur, and the media was reporting it as such, although it is unclear whether he really believed that or not or whether it was another effort to throw off other monster hunters by misleading them on what sort of animal they were looking for. After all, Onelli was probably aware that the evidence on hand did not match up with a plesiosaur, and author and cryptozoologist Austin Whittall has said of it:

We know now that it would have been impossible for a plesiosaur to adopt a “swan-like” pose or even lift its head and neck above the water’s surface. Its body would not allow such a feat. Sheffield’s comments about the foot print of a very heavy foot could not have been made by a plesiosaur either; the creature’s flippers would not have left a “foot print”; instead, like a turtle track, its trail would seem to be made up of lots of shallow dips made by its back flippers as it pushed itself along the ground, if and when it ever went ashore. Onelli’s repeated remarks regarding svelte necks and swan-like postures, implying that the beast was a plesiosaur, may have been part of his deceptive plan to mislead those who may try to capture the animal before he had the chance to do so.

The expedition went ahead as planned, led by a friend of Onelli’s by the name of Emilio Frey, and it included a mix of various members with their own useful skill sets for the task at hand, including, a taxidermist, freelance reporter, Associated Press correspondent, and several experienced game hunters, as well as the Zoo’s administrator, José María Cinaghi. They set out on March 22, 1922, and they soon got wind of sightings of a strange creature at a nearby place called lake Huechulafquen, of which Frey would write:

Many times I heard respectable neighbors of Junín de los Andes say that in the Lake Huachi-Lauquen, at dusk, an animal often appears on its surface, which has more or less the same features of the one that is said to have been seen in Esquel. Very long neck, lizard head, body that must be enormous, because when it submerges it produces a sort of “boiling” in the waters.

They eventually reached Sheffield’s remote cabin, where he lived with his Argentine wife, but oddly Sheffield himself was not there to join them, and instead his son José went with them, leading them to the lake that the creature supposedly inhabited. It turned out to be a rather small and shallow lake, not much more than a large pond and with a maximum depth of only 17 feet, and it did not seem to really have many fish at all, certainly not enough to support a lake monster, further reinforcing Onelli’s idea that their quarry was a giant ground sloth that periodically visited the lake rather than a large amphibious creature that lived there. There they were shown some faded footprints from the alleged beast that measured about one-foot-wide, but these were fairly old and degraded and no new prints could be found. Frey himself believed that the animal had left the tiny lake and swam downstream to Lake Puelo via the Epuyén River, so they expanded their search, along the way collecting reports from the locals that confirmed there was a mysterious amphibious monster frequently seen in the area. 

The expedition continued trudging through the thick, nearly impenetrable mosquito infested jungle in search of the elusive creature, combing the shores of the Epuyén River and Lake Puelo, but ultimately they were forced to postpone wvweything when winter approached and the following summer they called it off altogether after finding no further evidence. The consensus at the time was that whatever it was had possibly taken the river off to parts unknown. Interestingly, Whittall has through his own research for his site Patagonian Monsters found that Sheffield, the one who had brought the existence of the creature to Onelli’s attention in the first place, was not the one who actually saw the creature, but rather his daughter. Whittall says of it:

But, what did Mr. Sheffield actually see, that is, if he saw anything? Actually, he saw nothing, just some tracks; it was his daughter Juana who saw the creature with her brother Teddy. According to Juana, when she was 10 or 12 years old, she saw a “big creature” and told her father. He too had seen the tracks close to the lake where they usually hunted ducks; “the tracks were wide, but it seemed that the creature had short legs.” In an interview back in the 1970s she added that it “did not have a head or a tail, it looked like a [tree] trunk”; later, in 1995, aged 85, she gave a more detailed account and told that it was not her father, but she who first saw the creature’s tracks.

They resembled “cart tracks”, which surprised them as they were in the soft ground of a “mallín” (bog) by the lake. It seemed to them that something heavy had dragged itself through the plants. She believed that these were “paw marks” and that the creature that made them had a long body and short legs and “where it passed with its belly or body it squashed the small plants.” She recalled that by the lake something frightened their dog and they noticed tracks that went into the lake and surfaced on the other shore, she also saw something, saying:

'It was half red, half yellowish, nearly the color of leather sole. The animal’s fur was like hairs or feathers. They looked like hairs. We did not see its tail or head. We saw the part of its torso. It was lying there, sleeping in the sun […] That animal walked over a dead cow and did nothing to it; apparently it did not eat meat.'

In the end this particular monster was never found, and it just adds to the long list of supposed mystery monsters lurking about the wilds of the Amazon. What was going on here, and was there ever anything to it at all? Sheffield was described by many as an honest and astute witness, so what did he see? Was this a new type of animal, a misidentification, or what? Considering the age of the report and the lack of follow up it seems as if we will never know for sure.

You can read more about this monster and others in the Patagonian region in Whittall’s excellent book Monsters of Patagonia.

Brent Swancer

Brent Swancer is an author and crypto expert living in Japan. Biology, nature, and cryptozoology still remain Brent Swancer’s first intellectual loves. He's written articles for MU and Daily Grail and has been a guest on Coast to Coast AM and Binnal of America.

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