Nahuelito

Also Known As: little Nahuel, a diminutive of Lake Nahuel Huapi, Mapudungun nahuel, jaguar, and huapi, island
Region/Culture: South America
Mythos: Cryptids, Argentinian Mythology
Primary Type/Nature: Monsters and Beasts
Mythical Attributes: A large unidentified animal held to live in Lake Nahuel Huapi, known almost entirely by wakes, humps and dark lines on the water rather than by any close encounter.
Role in Mythos: It is Patagonia’s resident lake monster and Bariloche’s most durable story about itself.
Relation to Humans: Nobody has ever been hurt by it, and nobody has ever produced it. It has been hunted by a zoo director, banned from being hunted by a provincial governor, and put on a carnival float, and it has outlasted all three.

The grass would not stand back up. That was the part the hunter kept returning to in his letter: a track pressed through the pasture around the lagoon by his post, flattened as if a very heavy cart had been dragged across it, and the blades staying down afterwards. Out in the middle of the water there had been an animal, and the head on it was like a swan’s, if a swan were monstrous. From the way the water shifted around it he guessed at something built like a crocodile. He wrote all this from Esquel on the nineteenth of January 1922, and he was vague about exactly where the lagoon was.

The letter went to Clemente Onelli, director of the Buenos Aires zoo, and what Onelli did with it over the following ten weeks is the reason anyone in Argentina now says the word Nahuelito.

The lake it eventually attached itself to lies four hundred kilometres to the north, along the border of Río Negro and Neuquén. Nahuel Huapi is Mapudungun for island of the jaguar, which is a name from a time when the great spotted cat still ranged that far south; by 1902 Roberto Lehmann-Nitsche was writing about the jaguar’s retreat as a thing already finished. The lake is cold, glacier-cut, and shaped like a hand with the fingers spread, its arms running back between forested mountains until they are out of sight from anywhere. Since 1934 the country around it has been Argentina’s first national park, seven hundred and seventeen thousand hectares under the ice of Cerro Tronador.

The monster’s real ancestor is not folklore but a scrap of skin. In 1898 a piece of mummified mylodon hide came out of a cave in Última Esperanza and passed briefly through the Museo de La Plata on its way to London. Florentino Ameghino got hold of a cutting of it, decided the freshness of the thing meant its owner had died recently, and rushed a paper into print announcing a giant ground sloth still living in Patagonia. He gave it a name, Neomylodon listai. Hunting parties began arriving from England and the United States within the year, and none of them found anything.

What Ameghino added next is the part that matters here. Writing to Oldfield Thomas in October 1898 he said the Tehuelche called the animal the Jemmich, knew it very well, and had always had their accounts dismissed as fables; he placed it in dens along the shores of lakes Colhué, Fontana and General Paz and the Senguer and Aysén rivers. The trouble is that the people who went and asked could not find it. John Bell Hatcher, who spent three years in Patagonia and camped repeatedly with southern Indigenous groups in the very districts Ameghino named, reported in 1899 that he had heard no such tradition from them at all, and that they took no special care for themselves or their horses in the supposed haunts of the Iemisch. Tournouër said the opposite in 1901, that his companions feared the Hymché so much it was hard to separate what they knew from what they imagined. Lehmann-Nitsche settled it to his own satisfaction in 1902: the word most probably meant the otter, with a few traits borrowed from the jaguar, and the ground sloth had been gone so long that no memory of it survived in the languages or the legends of the Indians. When four researchers at the Museo de La Plata went back through the whole affair in 2024 they could not find the creature in the Mapuche or Aonikenk record either, and suggested that the terror had been Ameghino’s own sales technique. The monster was younger than the science.

So when Sheffield’s letter reached Onelli, Onelli read it as the sloth. He said so in a note that ran in La Nación on the sixth of March 1922, and the paper set a question under the headline: could it be a plesiosaur? That subheading did the rest. Within days the animal had a name it would never lose, and Onelli spent the following weeks explaining to anyone who asked that plesiosaur was a pseudonym the newspapers had given it, that he was after a large edentate, that he wished to be very clear the remains found in 1897 were not fossils. Nobody listened. There were tangos, three at least, and a brand of cigarettes, and Caras y Caretas advertising a fashion pin in black enamel called El Plesiosauro. Satirists wrote letters in the animal’s own voice to the president of the Argentine animal protection society, asking to be sheltered from Onelli under the 1891 law. The governor of Chubut decreed that hunting the plesiosaur was forbidden, and Onelli had to go to a national minister to get the decree undone. A Montana paper announced that the latest dance step was the Plesiosaurian Glide of Patagonia.

The expedition left Buenos Aires on the night of the twenty-third of March, without Onelli, who was ill and who had planted a false itinerary in the papers to shake off followers. Emilio Frey led it, with a champion marksman, a taxidermist from La Plata, the zoo’s administrator and two reporters. They reached Nahuel Huapi on the thirtieth. Frey had already written to Onelli from Bariloche a week earlier with something better than anything the expedition would find: the people around Lago Correntoso, just north of the big lake, had seen a large animal in the water more than once, at certain times of the year, and they called it el Cuero, the hide, and said it was like a sea octopus. That sentence is the moment the story arrives at this lake. On the seventeenth of April the party drove south to El Hoyo de Epuyén and reached Sheffield’s lagoon on the twentieth, where they found his wife and children; the man himself was convalescing in a village near Esquel. They worked the shallow water for days, at one point from a raft. They were back in Bariloche on the twenty-eighth, tried Lago Gutiérrez once more, and went out down the Limay by boat on the third of May. Somewhere in the middle of it Frey took time off to go to Buenos Aires about the founding of the Parque Nacional del Sud, which makes him a man who failed to find a monster and succeeded in starting the first national park in Latin America in the same six weeks.

At the Bariloche carnival the following February, a sawmill owner named Primo Capraro built a plesiosaur on a Ford truck chassis out of timber and sacking, rigged it to move, and paraded it through town with a man playing Don Clemente carrying a syringe. The Italian-language paper in Buenos Aires ran the result as news: the plesiosaur has been captured. The float came out for several carnivals afterwards until it burned in the sheds at Capraro’s mill. Onelli died in October 1924.

The idea stayed in Bariloche without a name for nearly fifty years. Then in 1970 a journalist printed a supposed sighting under a headline that gave it one, and the diminutive turned out to be the whole trick. Not a plesiosaur, not a surviving sloth, not the hide in the shallows, just little Nahuel, the lake’s own, half monster and half pet. Sightings and shaky videos have kept arriving ever since, and the town has never once discouraged them.

What Nahuelito has going for it is the water. The lake is deep and long and folds out of sight, a wake outlives whatever made it by several seconds, and flat grey morning light on that surface will produce a moving dark line for anyone patient enough to wait. What it has against it is the entire record. In more than a century nothing has been caught, stranded or recovered, and every organised attempt has come back empty, from the sloth hunters of 1899 to Hesketh Prichard’s grandson, who came out in 2001 to mark the centenary of his grandfather’s failure and repeated it. The naturalists who bothered to check concluded the creature was probably an otter. The emblem of the national park that now surrounds the lake is an otter.

Frequently Asked Questions

What is Nahuelito?

Nahuelito is a large unidentified animal said to live in Lake Nahuel Huapi in Argentine Patagonia, near the city of Bariloche. It is a modern legend rather than an ancient one: it grew out of an 1898 claim that giant ground sloths had survived in Patagonia, and it acquired its plesiosaur shape from a newspaper subheading in March 1922.

Where does the name Nahuelito come from?

The name is a Spanish diminutive of the lake, Nahuel Huapi, which is Mapudungun for island of the jaguar. It appears to have entered print in 1970, when a journalist published a supposed sighting under a headline announcing that Nahuelito had shown his face. Before that the animal was known in Argentina simply as the plesiosaur.

Did anyone ever go looking for it?

Yes. In March 1922 Clemente Onelli, director of the Buenos Aires zoo, sent an expedition to Patagonia after a letter from the hunter Martín Sheffield describing a swan-headed animal in a lagoon. The party searched Sheffield’s lagoon at El Hoyo de Epuyén and several sites near Bariloche for weeks and found nothing at all.

Is Nahuelito part of Mapuche or Tehuelche tradition?

Not directly. Florentino Ameghino claimed the Tehuelche knew the creature as the Jemmich, but naturalists who worked in Patagonia at the time could not confirm the tradition, and a 2024 study at the Museo de La Plata failed to find the being in the Mapuche or Aonikenk record. Local people around Lago Correntoso did report a water creature in 1922, but they called it el Cuero, the hide, which is a separate being in Chilean and Argentine folklore.

Has Nahuelito ever been photographed or captured?

No. Nothing has ever been caught, beached or recovered in more than a century of reports, and the photographs and videos that circulate are distant and inconclusive. Contemporary sceptics offered ordinary explanations from the start, including one American geologist who suggested that what Sheffield saw was a large water snake.