Many books and articles state that the legend of Nahuelito dates back to before the arrival of the Spaniards (earlier than 1540). These Conquistadors then heard about it from the natives at Lake Nahuel Huapi and recorded it in their chronicles.
For photographs and more information on lake Nahuel Huapi click to see our post: Lake Nahuel Huapi (Tiger Island) - "Nahuelito's home".
This is false. Not one reference of the beast can be found in print before the early XXth century. None of the colonial period chroniclers or the priests (Laguna, Guglielmo, Mascardi, and Menendez) who set up missions around the lake in the late 1600s and early 1700s mention it. Neither did the first explorers (Moreno, Fonck, Steffen, and Cox) who actually rowed across the lake, exploring its coves, fjords and islands.
It is revealing that during the plesiosaur furore Onelli mentioned several alleged sightings of strange creatures in Patagonia but not one is dated prior to the 1880s; and none were recorded at Lake Nahuel Huapi.
So, despite what has been written in sensationalist articles, it is only in the 1920s that we find the first printed record of a strange water creature in Nahuel Huapi Lake. Not earlier.
Nahuelito – its first printed appearance.
It was apparently first seen around 1910, but it was only made public in 1922, coincidentally with the Plesiosaur expedition. The article was published in the Toronto Globe, Canada, April 6, 1922 under the headline “Local man lays claim to having caught sight of gigantic plesiosaur”. The man named George Garrett said that about 1910 as a manager of company on Lake Nahuel Huapi while sailing in “an inlet called Pass Coytrue”, he saw :
"an object which appeared to be 15 or 20 feet [4,5 or 6 m] in diameter, and perhaps six feet above the water [1,8 m]. After a few minutes, the monster disappeared. On mentioning my experience to my neighbours, they said the Indians often spoke of immense water animals they had seen from time to time."
This is also the first reference to Indians and “large water animals”; there were Mapuche myths regarding water creatures, but none of them mention “immense” animals.
Though there is no inlet named Pass Coytrue on the lake, the best fit size-wise is similar sounding “Paso Coihue”, at the base of Huemul Fjord (40°58’ S, 71°20’ W), one of the lake’s deep arms.
See my Nahuel Huapi map.
Not seen again until the 1970s.
The next sighting was at Lake Gutierrez in 1938 just 16 km [10 mi.] from the town of Bariloche (41°08’ S, 71°18’ W). However it is cited in unreferenced articles and we could not corroborate it.
It is often incorrectly stated, quoting an article published in Newsweek magazine, that in 1960 the Argentine navy pursued a large submerged object in the lake. This is absolutely false.
The article tells of the navy searching for an "unidentified undersea object” which was surely a cold war spy as it was close to a naval base in the South Atlantic. It does not mention Nahuelito but jokingly asks “Was it a whale? Or an amphibious flying saucer? Or the Loch Ness monster gone astray?”
No reports were published until the late 1970s, when one placid midday in February 1976, by the Parque Hotel, close to Bariloche, Aquiles Lamfre said he saw on the calm lake, at about 1.600 meters (1 mi.) from the shore, a whirlpool, and an “enormous animal with a dark back and long neck with a snake-like head […] it then submerged”. Eleven years later he saw its body again (no head or neck this time).
In autumn 1976, my parents’ friends, “Coca” and Vincent Trussle saw something unusual; their home, “Cari Hue”, overlooked the lake and she had seen strange things in the past, but had explained them as currents, wind, etc., this time she saw something odd. Just one kilometer closer to Bariloche, Trussle's friends Bill and Hilda Rumboll saw the same thing at the same time. They all agreed that the “bicho” (critter) always turned up in February.
Hilda Rumboll's sighting was published in March 1978 (Revista Siete Días Magazine “¿Monstruos prehistóricos en Bariloche?”) and she recalled that it was a beautiful fall afternoon, the lake was very calm: “something odd was crossing the waters at a considerable speed, leaving a great wake”. She and her husband looked at it through binoculars and noticed what “seemed like a long swan’s neck. Then it turned towards the coast and it took on the appearance of a post and then it disappeared in the midst of a great stirring of water”. She judged its size as being 5 m (16 ft.).
In May 1979 people by the lake reported seeing something moving in the water about half a kilometer from the shore (1,600 ft.) estimating its size as 5 m, others believed it was just a tree trunk.
During the 1980s, a local reporter, Carlos Bustos, named it Nahuelito.
In October 1986, Ms. Stella Maris López, saw an “oversized animal” with a snake-like triangular head and a pair of scale covered humps.
December 1986, an Engineer, Guillermo Varzi (or Barzi) while returning in a speed boat from a picnic at Bahia Lynch on Quetrihué Peninsula saw something moving at about “25 or 30 km per hour [15 - 18 mi. per hour]”; his daughter Martina took a photograph, which was published in Diario Rio Negro [daily]”. He said that “at first I thought that it was a submarine. Then I saw a serpent head and behind it black fins like those of a dolphin or a shark”.11
In November 1987, José Ulesia and other 26 staff members of the Centro Atómico Bariloche saw the dark back of an animal in the lake close to Playa Bonita.
Also in 1987, a former pilot of Austral Líneas Aéreas airline, Alfredo Julio Passo, captain of the tourist vessel “Paisano”, saw a “head like that of a black snake”.
Local newspaper “Rio Negro”, reported on January 22, 1988 a sighting that occurred right in front of the city of San Carlos de Bariloche, close to the City Hall. A group of workers of the telephone company, a Fire fighting brigade and an employee of the Forest Department were witnesses of this creature; they saw “a great wake of froth in the lake, about 15 m [49 ft.] long, and at its tip there was a dark spot, similar to an animal’s back”. Despite using binoculars, they could not make out what it looked like.
The Forest Department employee said that she had seen “two humps” and when using binoculars she saw a “great dark splotch that moved at great speed”.
It was seen again, and filmed eleven days later. The short clip whose author is unknown showed something moving quickly across the waters of Lake Nahuel Huapi, leaving a wake and at least two dark objects creating it. A witness at Playa Bonita noted its “angular head of a giant snake and look of an antidiluvian animal”.
In 1989, a group of tourists led by Isabel Muller saw a creature 20 m long (66 ft.) moving under the water. One of the group, Jorge Brodo, photographed it and said it was “similar to a submarine underwater though its movement was too flexible”. 
In 1990, B. Aires daily “Diario Popular” reported a sighting close to Isla Victoria, where witnesses saw a “strange hump or [animal’s] back”.
On the evening of January 1, 1994, Jessica Campbell and Paula Jacarbe while on the beach at San Pedro Peninsula with a calm lake saw the animal appear close to the shore. It was as big as a whale and its back showed many humps, two small fins; they even heard it breathing. But, like most sightings they did not see its head. It reappeared twice and when it swam straight towards Ms. Campbell as she sat on a rock by the shore, she ran away from it.
In September 1993 a video showing a strangely moving wake in the Lake’s Campanario Arm was aired on the Bariloche Cable TV program Buenos Muchachos. It can be seen on YouTube, we insert the clip below:
It was seen during the summer of 1996 but not in 1997; it reappeared in January 1998 at a stream, Ragintuco, just north of Huemul Fjord. A couple, Graciela Carello and Rubén Ehara were fishing there when they the calm water surface began to “fill with white foam and a dark brown back began surfacing […] the animal must have got frightened because it slid under water causing great waves […] its back measured about 2 meters [6.5 ft.].”
In 2000, Christian Muller, 11 km (6.8 mi.) from the center of Bariloche, at 7 AM during a cloudy windless day early in summer, saw what he took to be a boat because of its wake. However the dark color called his attention, as no boats at the local nautical club had dark hulls. Suddenly the big dark object submerged in the lake.
In April 2006, three photographs of Nahuelito were anonymously left at the reception desk of the local daily “El Cordillerano”. They are very likely fake.
More recently, in November 2007 a woman named Rosalba Painefil saw, close to the mouth of Ñirihuau River, to the east of Bariloche, an “animal or something like it […] enormous and not at all like a cow or a deer […] it came out to the shore and then went back in to the lake, disappearing […] it had like a head, but it did not look like anything known; it was very big".
In April 2008, not one but two separate “things” resembling “bus roofs” or “rectangular submarines” surface close to Bariloche's downtown district making a lot of bubbles. Their size was estimated at 8 by 4 m and 6 by 3 m (26 x 13 ft. and 20 x 10 ft.). One jutted out of the water some 40 cm (16 in.) and looked like a “tortoise” or a “hamburger”; both shone brightly in the sun.
In November 2008, a fake-looking photograph was published in the Bariloche daily, El Cordillerano. The photographer said that he had thought that there were some huillínes fluttering around under the water. The image looks like a floating trunk, definitively a fake.
What is Nahuelito?
These descriptions are quite varied, and although some are consistent (snake head, long neck, large size) and hinting at a huge plesiosaur-like being, most depict turbulent waters, wakes, “dark humps”, bubbles, foam and fast moving animals with small heads.
Plesiosaurs are not an option as they have been definitively extinct for 65 million years so another explanation must be found.
Setting aside the notion of a hoax (one that helps promote tourism and keep Bariloche in the public eye), there is the possibility that people see what they think they should see. Knowing that there have been sightings of a plesiosaur-like being in the lake, anything that looks unusual will be attributed to this beast.
The most likely explanations
Plesiosaur. Author’s sketch.
When seeing at a distance a snake-like monster with many humps swimming with a winding motion, the most likely explanation is that it is not what it seems (giant aquatic reptile), but a group of Huillines (Patagonian otters).
Huillínes (Lontra provocax) enjoy swimming in a playful manner, diving and resurfacing and when swimming in line something they often do, they may look like an extinct plesiosaur. See my post on swimming otters with photographs.
Close up, their wet fur can give the impression of being scales (see my post on this interesting similarity: reptilian scales on otters).
Under very calm conditions (such as Trussle's and Rumboll’s sighting) the wake caused by a creature too small to be seen like a group of swimming birds such as the Huala (Podiceps major) taking off and landing can create intermittent wakes like some underwater creature surfacing.
Different objects may also be mistaken for lake monsters such as fish swimming near the surface, bobbing logs or long-necked birds.
Interestingly, during autumn (March) is the Red Deer’s (Cervus elaphus) breeding season. During this period called the rut, stags aggressively compete for the attentions of the females (hinds).
Stags are also known to swim across the lake from Huemul Peninsula to Victoria Island searching for females, an open and exposed stretch 2 km (1.25 mi.) wide and over 200 m (655 ft.) deep.
An inexperienced observer would swear seeing Nahuelito if confronted with a swimming deer.
Another option is swimming wild boars. These exotic (they are not native to Patagonia) animals were brought from Europe by an Argentine aristocrat to his hunting lodge at Huemul Peninsula in the 1911 and set loose. By 1999 they had swam across the open lake between the peninsula and Victoria Island, settling there. See my post on Patagonian bears for more details.
Another little known factor is the seiche, a type of wave that is present in many lakes, but is usually unnoticeable except during periods of unusual calm. Seiches may cause an unexpected stirring in the water, a change in its color. They arise when a strong and constant wind, blowing over the lake’s surface forces the water to accumulate at the down-wind shore. When the wind stops, the water level will begin to return to its original equilibrium through a series of broad oscillations across the entire lake. Often referred to as the bathtub effect, seiches cause the water levels to rise and fall along the coast and waves reflect back and forth, mixing and merging to forming vortices.
At Nahuel Huapi's Campanario Arm, this phenomenon is particularly notable due to its shallow end and its long and narrow shape, which allows wind-caused seiche to form. Furthermore; it causes an anti-clockwise rotating vortex just like the one seen in the 1993 YouTube video.
It was at San Pedro, on the Campanario Arm that Campbell and Jucarbe saw their monster on a calm day. It may have been a seiche.
Furthermore, bubbles of natural gas from an oil field, suddenly released from faults that lie under the lake's bed could explain froth, wakes and dark patches reported by many observers.
This coincides with a local belief that “the mythical Nahuel Huapi monster appears during summer season on hot days and with absolute lack of wind”.
Seiches can also stir the water column moving pollutants, sediments and organic matter towards the surface. This could cause colored patches on the lake surface. Furthermore, summer causes warming of the deeper water layers. Some Bariloche experts suggest that warmer water in summer causes fermentation of organic matter lying on the shallow lake bed areas which causes bubbles of carbon dioxide to surface.
Light refraction can cause mirages on the water distorting the shape and size of things giving them an unrecognizable form. These optical effects can be caused by the wind giving the water a matt appearance interspersed with calm areas reflecting mountains as dark ovals which can appear as humps if seen from the shore.
The mythical “Cuero” (cow hide).
Garret had said that “the Indians often spoke of immense water animals they had seen from time to time”; since then many have attempted to link Nahuelito to the Mapuche “Cuero” myth. But, as we will see below, they are very different beings.
The “Cuero”, which in Spanish means hide or leather, also known as Manta (blanket) or Devil’s Manta, is a Mapuche belief.
The creature’s name is due to its shape, like that of a large extended cow hide; its Mapuche name is Threquelhuecuvu (Threlque or Thelque meaning hide and Huecuvu malefic spirit – i.e. gualicho), though it is also known as Trelquelafquen (lake hide)
The Cuero lives in lakes and rivers but can also be found in the sea. It prefers small dark lakes. Naturalist Juan Ignacio Molina described it in the late 1700s as a man eating lake monster that was “nearly circular, like an extended cow hide”.
On its body’s edge it has sharp claws, and it is said that its head has tentacles and a pair of bulging red eyes. Its mouth is under its body, in the center, resembling a suction pad, through which it sucks the body fluids of its victims, killing them.
Amphibian, it comes out of the water and lies concealed on beaches where it captures men and animals that happen to walk over it, by wrapping itself quickly around them, holding them fast with its claws and suffocating them to death. It then quickly drags its victim to the lake to eat it. The natives killed the cuero by throwing thorny cacti into the water, that when grabbed by the beast, pierced it causing its death.
Latcham believed that the cuero myth originated from a squid species that can grow to a length of 1,2 meters (3.9 ft.) without taking into account its tentacles.
According to Father Juan Ignacio Molina it was “a monstrous type of Manta ray”, or perhaps a squid with cat-like nails; the 'Seppia unguiculata'" (its Latin name means “clawed” Seppia).
This giant squid which can measure up to 2 meters (6.5 feet) in length is also known as Taningia danae, is “armed with a double row of joints or sharp nails, similar to those of a cat, that withdraw –like those- into a sort of seath”.
During the 1922 “plesiosaur expedition” [we will write about this in another post] part of the group was invited by a local potentate, Primo Capraro to visit his lodge at Lake Correntoso (40°44’ S, 71°40’ W) so that they could look into the “cuero” myth. They sailed up Nahuel Huapi Lake, to Correntoso, where they searched in vain.
The ray theory is the most reasonable explanation, in fact the shape and size of the cuero are similar those of fresh water stingrays.
However these apparently do not live in the Patagonian lakes or rivers, their habitat is in the Tropical to Temperate regions of eastern South America.
Nevertheless, after a 1976 accident that sent a bus full of tourists to the bottom of Lake Moreno close to Bariloche, rescue divers were sent in to fetch the bodies of those who had drowned. According to some of them, they saw “rays of a great size on the bottom of the lake”. but there is no formal mention of stingrays in any Patagonian lake in any published scientific paper.
South America is home to the only exclusively freshwater stingrays in the world, the family Potamotrygonidae. The closest to Patagonia live in the Paraná River basin. These rays have a sharp spike on the rear of their tail which they use for self-defense and, interestingly, their disk can be covered with small denticles, small to large thorns which are thooth-like in structure, and covered with a tough enamel.
Rays are dangerous, if stood on by an unaware person wading in the water, they bend their tail and strike with their sting inoculating poison; this causes a very painful wound that is slow curing and can ulcerate.
These rays can grow quite large, up to 1 m (3.3 ft.) diameter and have an elliptical shape; however none have “claws” along their edges.
Jesuit Father Falkner, who wrote extensively about Patagonia, noted that their very sharp barb can cause nasty wounds because it is difficult and painful to remove due to its serrated saw-like edges. The wound can get infected or cause tetanus and death.
If we accept the theory of a Guaraní origin for the Mapuche, we could assume that the Mapuche met the freshwater rays when they migrated to Chile from the Parana basin region.
It would be much more likely that they met rays by the sea on the South Pacific coast of Chile. They would have been amazed to find a dead manta ray washed up on a rocky beach. There are several sea rays in Chile: Dipturus chilensis, D. trachyderma, as well as the enormous manta rays Myliobatis chilensis and Mobula tarapacana.
But there is another intriguing option: Potamotrygonidae are related to the Dasyatid rays who often venture into fresh water in several parts of the world; one of these species can be found off the Chilean Patagonian coast. Maybe these Dasyatids swam up the rivers into the Andean lakes and their denticles were taken for claws.
Nahuelito the “monster” does not exist.
It seems that Nahuelito can be explained with huillínes, logs, or seiches, and that the cuero may be a freshwater stingray or a myth born elsewhere and later taken inland by the Mapuche.
Over nearly forty years, the author has spent many hours on the lake in boats and along its shores, fishing, sunbathing or just looking at the great scenery and has not once seen anything unusual. No ominous shadows under the water, no humped monsters or swan-necked beings.
However, as we will see in the following chapter, most of the Patagonian lakes have their own mysterious beings; this is a fact that can’t be ignored. Lack of evidence is not evidence of absence.
So it could be possible that there is some strange animal –though not a Plesiosaur- living placidly concealed in the deep blue waters of Nahuel Huapi.
 Coleman, L., and Huyghe, P., (2003). The Field Guide to Lake Monsters, Sea Serpents and Other Mystery Denizens of the Deep. New York: Jeremy P. Tarcher/Putnam. pp.120+.
 Picasso, F., (1998). South American Monsters and Mystery Animals. Strange Magazine, N° 20. 12-1998. 28–35.
 Newsweek magazine. The Wily Whatzit?. 22.02.1960. pp. 57.
 Jarré, S., (2004). Guarida de Monstruos. Los 32 rumbos de la Rosa de los Vientos. Año 1. N° 3. IV: 42 – 47.
 Duda (1979). Noticiero de lo insólito, En Argentina: monstruo parecido al de Loch Ness. (409), 1, 02.05.1979.
 Diario Hoy, (1998) Volvió a aparecer “Nahuelito” en Bariloche. La Plata, Argentina. 11.01.1998
 Diario Río Negro, (1988). Otra vez Nahuelito. General Roca, Argentina. 02.01.1988.
 Diario Río Negro, (1988). Logran filmar al extraño animal del lago Nahuel Huapi. 07.02.1988.
 Billiken (1989). Issues 3616-3633. Ed. Atlántida. pp. 49.
 British Columbia Scientific Cryptozoology Club. Nahuelito (Lago Nahuel Huapi).
 Eberhart, G., (2002). Misterious Creatures: A guide to Cryptozoology. S. Barbara: ABC Clio. pp. 366.
 Signato F. Nahuelito – Bariloche – Buenos Muchachos - Año 93.
 La Gaceta (2006), ¿Reapareció Nahuelito? Tucuman, Argentina. 18.04.2006.
 Noticias de Bariloche, (2007). Curioso Avistaje de una Vecina. Bariloche, Argentina. 15.11.2007.
 Bariloche 2000 Diario Digital, (2008) Uno ya era bastante. Bariloche, Argentina. 30.04.2008.
 Infobae.com., (2008). ¿Es 'El Nahuelito'? B. Aires, Argentina. 19.01.2008.
 Buscaglia, G. et al., (1997). El futuro del Nahuel Huapi: El modelado numerico como herramienta de prediccion y planeamiento. Instituto Balseiro y Centro Atomico Bariloche. 20.01.1997. Online.
 Centro Atómico Bariloche - Instituto Balseiro (2001). Proyecto Simulación computacional en fluidodinámica ambiental.
 Lehn, W. H., (1979) Science, Atmospheric Refraction and Lake Monsters . Jul 13;205(4402):183-185.
 Rothschild, D., et al. (1996). Protegiendo lo nuestro: Pueblos indígenas y biodiversidad. Quito: SAIIC. pp.43+.
 Molina, J., (1986). Ensayo sobre la historia Natural de Chile. Santiago: Ediciones Maule. pp. 208.
 Ibid. pp.233.
 Latcham, R., (1924). La organización social y las creencias religiosas de los antiguos araucanos. Santiago: Cervantes. pp. 575+.
 Ibid. pp. 610.
 Rey, C., (2007). Nahuelito: El misterio Sumergido. Bariloche: Caleuche, 2007. pp. 75.
 Berra, T. M., (2007). Freshwater Fish Distribution. University of Chicago Press. pp. 22 +.
Copyright 2009 by Austin Whittall ©