Neomylodon

Patagonian ground sloth Statue Reconstruction A statue of Mylodon at Puerto Natales, Chile, photographed by Wikipedia user Haplochromis. Identikit illustration of Neomylodon by HourDark on Reddit. Category Living fossil Proposed scientific names Neomylodon listai (Ameginho 1898), Grypotherium domesticum (Hauthal 1900), Mylodon listai (Ameginho 1898) Other names Hairy pangolin, mysterious quadruped, Patagonian Mylodon Country reported Argentine and Chilean Patagonia First reported 1898 Prominent investigators • Florentino Ameghino • Hesketh Prichard • Clemente Onelli • Bernard Heuvelmans • Elio Massoia • Charlie Jacoby • Austin Whittall

The Patagonian ground sloth (Neomylodon listai or Grypotherium domesticum) was a cryptid ground sloth proposed to exist in the interior of the Patagonian plains by the Argentine palaeontologist Florentino Ameghino at the end of the 19^th Century, based on a number of alleged sightings and on the discovery of a piece of skin. Ameghino confused the issue by connecting the animal with stories of the aquatic, otter-like predator iemisch, and later writers made connections with other Patagonian cryptids such as the succarath, lobo-toro, and ellëngassën. The story caused quite a stir amongst turn-of-the-century naturalists, and several international expeditions were sent to Patagonia to search for more evidence.

Attestations

Francisco Moreno received reports of a terrifying but rare hairy beast from the Tehuelche and Gennake Indians. The explorer Ramón Lista reported the Tehuelche belief that the Sierra Carhuerne, Santa Cruz, was home to "evil spirits and monstrous quadrupeds" which once carried off a whole family of Indians, although Bernard Heuvelmans wrote that, as none of the family survived to tell the tale, their disappearance was simply attributed to the mysterious quadrupeds. Santiago Roth was told by a Tehuelche chief named Kankel that a very savage beast used to live near Lake Buenos Aires in Santa Cruz: when it roared, all the other animals fled, and one day it supposedly killed a herd of horses belonging to Kankel's grandfather. Other Tehuelche legends describe cattle-sized animals with short legs and claws. Some Indians in around 1913 or 1921 said that their fathers frequently saw "an enormous giant that was four meters tall and thick as an ox" in the fields close to Sarasola Cave, near Lake Musters in the Argentine province of Chubut. Ameghino claimed that he had heard many stories of a:

“

...mysterious quadruped [...] in the interior of the territory of Santa Cruz, living in burrows hollowed out in the soil, and usually only coming out at night. According to the reports of the Indians, it is a strange creature, with long claws and a terrifying appearance, impossible to kill because it has a body impenetrable alike to firearms and missiles.

”

Later, in 1900, an item in Caras y Caretas declared that there was "no shortage" of alleged eyewitnesses who claimed to have seen the animal from some distance in Chubut. Ivan T. Sanderson attributed stories of "giant footprints" like those of humans discovered in Patagonia to ground sloths, the fossil trackways of which have been mistaken for giants' footprints in the past. Roy P. Mackal also referred to more recent rumours of such an animal, with burrowing habits. Clemente Onelli cited a number of miscellaneous reports which he believed referred to Mylodon.

Other Patagonian monsters connected with the giant sloth include the succarath, lobo-toro, and ellëngassën, and similar hairy, long-clawed, underground monsters appear in myths and sightings from Patagonia to Tierra del Fuego, as do hairy humanoid creatures living in the mountains.

Sightings

~1890

Argentine explorer, administrator, and polymath Ramón Lista (1856-1897) supposedly claimed to have encountered a ground sloth-like animal in Santa Cruz.

Ameghino wrote that Ramón Lista, an explorer and governor of Santa Cruz, told himself, his brother Carlos Ameghino, and several other people of a sighting he'd had (dated to 1890 by Clemente Onelli) of a hairy pangolin-like creature, which he came across while riding in the interior of Santa Cruz:

“

He came across it one day during one of his journeys in the interior of the territory of Santa Cruz, but in spite of all his efforts he was unable to capture it. Several shots failed to stop the animal, which soon disappeared in the brushwood; all search for its recovery being useless. Lista retained a perfect recollection of the impression this encounter made upon him. According to him the animal was a pangolin (Manis), almost the same as the Indian one, both in size and in general aspect, except that in place of scales, it showed the body to be covered with a reddish grey hair. He was sure that if it were not a pangolin, it was certainly an edentate nearly allied to it.

”

Although Einar Lönnberg wrote that the animal seen by Lista could not have been Neomylodon or a relative on account of its much smaller size, Heuvelmans, noting that "even a rhinoceros is no bigger than a calf at one stage of its existence," suggested that it could easily have been a young individual.

Lista was dead by the time Ameghino published his Mylodon sighting. Francisco Moreno believed that Ameghino had made the story up, and although Ameghino thought that Lista had also mentioned the incident in one of his books, Arthur Smith Woodward could not find a record of the encounter in any of the Library of the Royal Geographical Society's collection of books written by Lista. Lista wrote forty-one books and papers in total.

~1895

See also Iemisch§1897

Florentino Ameghino claimed to have acquired his Neomylodon hide from an animal killed very recently, which he referred to as a iemisch. According to a letter from his brother Carlos which he published, Carlos had acquired the hide from a Tehuelche who owned it. Carlos also interviewed a Tehuelche named Hompen, who claimed that...

“

[...] while going by Senguer in Santa Cruz, [he] met a Iemisch on the road, which closed his way, and he fought with it, killing it by hitting it with his bolas.

”

However, according to Florencio de Basaldúa, who interviewed Ameghino, the specimens were flayed from the animal killed by Hompen himself, on the shores of Lake Colhué Huapí," which is fed by the Senguerr River. The true provenance of Ameghino's hide is unknown, and it has been suggested that Ameghino made the story of the killing up when rivals began to suspect that the specimens were from the Cueva del Milodon.

1898

Edward Chace, an American who lived in Patagonia in the late 19^th and early 20^th Century, claimed that:

“

A friend of [an Indian known to Chace] had followed a track like that of a wooden shoe with two cleats across the sole, until he caught sight of what he took for a hairy pig as big as a bull. Just a glimpse he had. Once or twice, long afterwards, on a still night in a forest, beside a glacier, Chace himself heard a trumpeting, something like a steamboat whistle. That was long before there was a whistle on any Cordilleran lake. He kept his secret until Prichard came out from England hunting for a live mylodon.

”

According to George Eberhart, who lists the encounter as an ellëngassën sighting, the first incident, in which the animal was actually seen, occurred in 1898.

1899

According to Florencio de Basaldúa, writing in May 1899, three men on an expedition to Chubut in search of the Mylodon, led by Illin of the Museo de La Plata, encountered and attacked a Mylodon, which chased them off, near Lake Musters.

“

Breaking reports, from Lake Musters, refer to an attack on the Mylodon by three expedition members of the party of the former librarian from the Museo de La Plata, and their flight from the invulnerability of the monster's armour and its aggressive fury; but it is certain that in the end he will fall prisoner of man.

”

However, Illin made no mention of the incident when interviewed about Neomylodon later in the year. Two decades later, in 1922, Clemente Onelli, who was gathering sightings of a "Patagonian plesiosaur" which he believed to be a Mylodon, wrote that an expedition to Chubut, allegedly "organised" by Basaldúa and commanded by an unnamed member of the Museo de La Plata, had to be abandoned when it was attacked by a Mylodon-like animal.

According to accounts published in various British, Australian, and American newspapers in 1900, the Daily Express expedition which was then searching for the Neomylodon in Patagonia was contacted by a Scottish traveller who claimed to have shot at an animal like a giant sloth the previous year.

1901

On 4 January 1901, Florentino Ameghino wrote to Hermann von Ihering concerning the Neomylodon and the iemisch, which he admitted could be two different animals, and sent him an issue of La Nación featuring a report "concerning the largest, which is supposed to be the Neomylodon". According to the Ameghino's letter, one man named Steinkanpen saw the animal, accompanied by two labourers called the Montesinos, and two teenage sons; while a second eyewitness, Zubizarreta, was accompanied by seven soldiers.

On 3 March 1901, Carlos Ameghino wrote to his brother Florentino claiming that "the mylodon has been seen this time in the mountains by the Gallegos River by neighbours of that place, and it is not improbable that any moment we may get the news that it has been hunted. This time it seems to me that it is true and serious, according to the reports I have".

Later that year, on 25 July, the interested Argentine surveyor Florencio de Basaldúa wrote to Ameghino claiming that he had "very important news on the Neomylodon Listai". Basaldúa had sent out messengers to confirm the report, and promised to inform Ameghino first if anything came of it, but the nature of his news remains unknown.

Lake monster connections

In 1899, Ameghino wrote an article connecting the skin with an animal called the iemisch, an aquatic monster which killed horses, a theory he had previously pushed in a number of Argentine newspaper interviews. According to his account, his brother Carlos had, in 1897, sent him some little bones which he claimed the Indians had said came from an iemisch, but Ameghino's subsequent description of the iemisch, based on Indian reports, bore no resemblance to a ground sloth, and Ameghino altered the number of toes on the creature to better fit Megatherium. Heuvelmans wrote that "Ameghino seems to have gone completely astray in accepting this theory of his brother's that the armoured skin came from the Patagonians' iemisch". More plausibly, Santiago Roth thought that a new, extinct genus of big cat, the bones of which he discovered in the Cueva del Milodon, might be the iemisch, leading him to christen the fossil Iemisch listai⁠—in honour of Lista's alleged sighting of the "pangolin". These bones, once suggested to actually represent the short-faced bear Arctotherium, are now believed to have belonged to either the Pleistocene jaguar Panthera onca mesembrina or the American lion (Panthera atrox), while the iemisch itself is believed by many cryptozoologists to be a kind of giant otter.

Ameghino's connection of Mylodon with the iemisch, a cryptid reminiscent of a giant otter or saro (Pteronura brasiliensis), caused much confusion.

Ameghino's iemisch theory came under attack even at the time, and he later defended himself in a letter to Hermann von Ihering, dated 4 April 1901, writing that "the references to Jemisch are exploited in ill faith. I have not described the Neomylodon by references but from the mentioned bones [...] and simply referred the descriptions of a large mammal that inhabits the Patagonian lakes [...] if these descriptions are not reliable, the blame is not mine [...] Probably there is not only one mysterious mammal living in Patagonia, but several".

Much later, in 1922, the Argentine naturalist Clemente Onelli also theorised that Mylodon could explain a Patagonian lake monster, in this case the "Patagonian plesiosaur". Although some sightings of the animal described it as having a long neck, Onelli privately admitted that he had deliberately put out exaggerated and misplaced stories in order to throw off any rival expeditions, and the original sighting turned out to have been describing an animal of which the neck was not seen. This cryptid is also sometimes speculated to be a species of giant otter, and possibly the same animal as the iemisch.

Ameghino also connected Mylodon with the succarath, a Patagonian cryptid reported in the 15^th Century, which was compared to a lion and an anteater. His succarath theory is better-regarded among cryptozoologists than his iemisch theory. Ameghino also suggested that, as with the succarath, Patagonian people had been using the Mylodon hide as clothing, explaining why the Cueva del Milodon hide had been cut and rolled up.

Physical evidence

Hides

The entrance to the Cueva del Milodon, seen from within the cave, photographed in 2006.

From left to right, Hermann Eberhard Jr., James Lovegrove Waldron, Ernst von Heinz, Teodoro Huelphers, Eberhard, and the unmutilated Mylodon hide.

The German rancher and adventurer Hermann Eberhard discovered the Cueva del Milodon (also historically called Eberhardt Cave, Last Hope Cave, and the Cave of Ultima Esperanza) in January 1895, north of Last Hope Sound and south of the Cerro Benitez, in what is now Chile's Última Esperanza Province of the Magallanes Region. Inside the cave, he found a large piece of hide, about 4'9'' long and between 2'2'' and 2'6'' wide, which looked fresh, but which he knew belonged to no known animal. It was found buried in earth, turned inside out and rolled up. A human skeleton was discovered elsewhere in the cave. Thinking that the skin was that of an unknown type of giant seal, Eberhard kept it hanging out for a year, until in 1896 he showed it to a visiting geographer, Otto Nordenskjöld, who found more pieces of skin, as well as a claw sheath, within the cave. His specimens were sent back to Sweden, where they were identified as Mylodon by Einar Lönnberg. Other souvenir hunters, including a party of Chilean Navy officers, also took pieces of the skin (requiring the use of a hatchet), and eventually Francisco Moreno, curator of the La Plata Natural Sciences Museum, took the square 18'' of hide which remained back to his museum.

Close-up of a piece of Mylodon hide from the Cueva del Milodon at the Museo de La Plata, photographed by André Ganzarolli Martins.

In 1898, someone brought a number of apparently fresh osteoderms to Argentine palaeontologist Florentino Ameghino. The provenance and current whereabouts of Ameghino's specimens are unknown: he initially wrote that "several little ossicles have been brought to me from Southern Patagonia". However, privately, he told Florencio de Basaldúa that the osteoderms and a piece of hide, both of which he showed Basaldúa, came from an animal recently killed on "the banks of Lake Colhué-Huapi, where it was hunted and killed by an Indian named Hompen, who is there in my service," The photograph printed in Basaldúa's article, however, is of Nordenskjöld's piece of skin. Ameghino later wrote that his brother Carlos had sent him a number of little bones from a iemisch killed by an Indian, publishing Carlos' own letter to him as corroboration. This letter also mentions Hompen's killing, but in a different context. During an interview published in El Magallanes on 11 June 1899, Ameghino said that his hide came from an animal killed by Hompen near the Senguer River, using a bolas. Moreno believed that Ameghino's story was a lie, and that his bones had come from Eberhard's skin: he requested to see Ameghino's specimens through the British Museum, but they were never produced. Ernst Haeckel, a Dr. Lux, Die Umschau, Edward William May, and The New York Press also all unsuccesfully requested photographs of Ameghino's skin. Bernard Heuvelmans later suggested that Ameghino's bones were sent to him by the souvenir-hunting Chilean officers.

In August 1898, Ameghino wrote a pamphlet on the Mylodon, in which he expressed belief that the animal was still alive, based on the condition of the bones and on a number of sightings he had collected, including the one allegedly made by Lista⁠—he believed the animal seen by Lista was the same as the animal from which the skin came because of its apparent immunity to bullets, suggesting it was armoured under its fur. In honour of Lista's sighting, and because Lista himself had been murdered, shot dead at Miraflores by his two Tobas Indian guides whilst exploring the Pilcomayo fairly recently, Ameghino named the animal represented by the skin Neomylodon listai.

Moreno, however, insisted that his own skin was very old, preserved only by the cool and dry climatic conditions in the Cueva del Milodon, a belief partially fuelled by his discovery of a well-preserved human mummy, of a race no longer found in the region, within a similar cave. To disprove Ameghino's claims (and believing him to have based his study on the Cueva del Milodon hide), Moreno arranged for the skin to be examined by eminent palaeontologist Arthur Smith Woodward, and presented his point of view in a paper read before the Zoological Society of London on 21 February 1899, supported by Harry Seeley, who cited the well-preserved remains of moas, woolly rhinoceroses, and woolly mammoths. The meeting "distinctly disagreed" with Moreno and Seeley (although one palaeontologist, Ray Lankester, suggested that the hide came from an unknown armadillo and not a sloth), and for a time it was believed that the remains were indeed fresh. In his description of the hide, Woodward said that he "should unhesitatingly express the opinion that it belonged to an animal killed shortly before Dr. Moreno recognised its interest, had he not been able to give so circumstantial an account of its discovery and strengthened his point of view by recording the occurrence of a human mummy of an extinct race in another cavern in the same district". He noted the presence of a covering of dried serum on part of the skin, which he said was "suggestive of grave doubts as to the antiquity of the specimen," although the chemist Vaughan Harley told him that similar dried serum had been discovered on ancient Egyptian mummies. He was more sceptial regarding the animal itself, saying that "it is indeed strange that so large and remarkable a quadruped should have hitherto escaped detection in a country which has been so frequently visited by scientific explorers," and he thought the skin was not connected to Lista's "hairy pangolin" because of the latter animal's smaller size.

The piece of skin discovered by Eberhard and sent by Moreno to London, where it is currently housed in the Natural History Museum.

Shortly after the paper was read, Woodward was able to read Otto Nordenskjöld's paper describing the specimens he had taken, which included a claw sheath. Zoologist Einar Lönnberg boiled a piece of Nordenskjöld's skin and extracted glue from it, "which proves that the collagen and gelatinous substances are perfectly preserved". Woodward felt that this indicated that "if the specimen is of any considerable age, it must have been very well protected against moisture and bacteria". Lönnberg was more pessimistic regarding the sloth's continued existence: disregarding the Tehuelche stories and rejecting Lista's pangolin due to its size, he wrote that Patagonia's inhabitants would have reported seeing the animal if it still lived.

Meanwhile, Otto Nordenskjöld's cousin, the archaeologist Erland Nordenskiöld, had visisted the cave and collected from the soil of the cave floor osteoderms, a layer of dung, butchered guanaco bones, and finely-chopped hay. After careful study of the osteoderms, Nordenskiöld concluded that they were referable to Glossotherium darwinii—now Mylodon darwinii—and, assuming that Ameghino's bones had come from the Cueva del Milodon, announced that Ameghino's Neomylodon listai was therefore a junior synonym. While his findings showed that humans had inhabited the cave, Nordenskiöld felt that people had settled there after the sloths had died out.

In April 1899, a La Plata Museum expedition under geologist Rodolfo Hauthal made a thorough examination of the cave, finding both ground sloth coprolites and evidence of human habitation, including apparent crude walls of boulders, a raised platform, and a midden containing mussel shells and animal bones. Beneath the midden layer was found a mass of partially-burned dung from a very large herbivore, dry hay, and the broken and sliced bones of Mylodon, horses, and a large carnivore. A second hide was found close to where Eberhard had discovered the first one. The layout of the chamber, the dung, the hay, and the damaged bones led Hauthal to the belief that the cave's human inhabitants had kept live Mylodons to slaughter, butcher, and eat: "the men who lived there ages ago were accustomed to stable their domestic animals in this part of the cavern, reserving the rest for their own dwelling place". Examination of the bones appeared to back this up, suggesting that the skull had been smashed in by a rock, while other bones had been cut with sharp tools. Furthermore, Spencer Moore's analysis of the dung showed that the Mylodons had been feeding on very cleanly-cut vegetation. It was even suggested that the animals had been truly domesticated as opposed to merely stabled for slaughter, and Hauthal consequently renamed the sloth Grypotherium domesticum.

The belief that the cave had been contemporaneously inhabited by man and sloth persisted well into the 20^th Century, and is discussed in cryptozoological works including On the Track of Unknown Animals (1955) and Searching for Hidden Animals (1980). A more likely alternative explanation for Hauthal's findings was not discovered until 1976, when Earl Saxon excavated a different part of the cave floor and found that there were in fact two layers of sloth dung, sandwiching between them a layer of human detrius: Nordenskiöld had seen only the lower layer of dung, Hauthal the upper. Consequently, it is now thought that sloths and humans inhabited the cave in alternating periods, never at the same time.

Although the failure of various expeditions to Patagonia to find evidence of a living Mylodon dampened the enthusiasm for the idea, Eberhard's hide continued to be quietly cited by works including the 1911 Encyclopedia Britannica, and the Ameghinos were corresponding on the subject until at least 1901. However, by the middle of the 20^th Century, carbon-14 dating had suggested an age of up to 11,000 years to 5,000 years, supporting Moreno's argument that the hides had been preserved by the cool, dry conditions in the cave. Neomylodon listai, Mylodon listai, Glossotherium listai, and Grypotherium domesticum are now all usually considered to be junior synonyms of Mylodon darwinii.

Besides Mylodon darwinii, other megafaunal animals known from the remains in the Cueva del Milodon include Smilodon populator, Pararctotherium or Arctotherium pamparum, Macrauchenia, Panthera onca mesembrina, up to three species of horse including Hippidion, guanacoes, and the Andean deer. Mylodon darwinii is the most numerous large animal, with a minimum of 23 individuals represented in various collections around the world. About 40 sections of skin from the cave are now also in different museums. During the Late Pleistocene, the environment about the cave was an open steppe dominated by cold, wet sedge-and-heather-grasslands. The Mylodon, and particularly their young, are believed to have been important prey items for the area's larger predators, such as Smilodon populator.

Hermann Eberhard

Otto Nordenskjöld

Francisco Moreno

Florentino Ameghino

Carlos Ameghino

Arthur Smith Woodward

Erland Nordenskiöld

Rodolfo Hauthal

Expeditions

Prichard, T. Barbury, and Scrivenor.

Charlie Jacoby, Prichard's grandson and a modern-day Mylodon hunter, standing with the statue at the Cueva del Milodon.

After meeting Ameghino, Florencio de Basaldúa wrote to Adolfo Saldías, Minister of Public Works, with the intention of leading an expedition to capture a live Mylodon. Saldías promised that, when he had the time, he would "contribute a large sum to the expenses of the ... hunt". In an early search attempt, Illin of the La Plata Museum went in search of the Mylodon in the mountains near "Lake Paz" in 1898, and, according to Basaldúa, was attacked by the animal near Lake Musters in early 1899. In 1899 there were between eight and ten expeditions in search of the Mylodon active: Chilean, Argentine, English, and French (André Tornouër).

One of the most notable early expeditions was the English one led by African explorer Harry Cavendish (later Henry Sheppard Hart Cavendish, 6th Baron Waterpark), with British Museum naturalist Edward Dodson. This expedition set out to search for the Mylodon—or, as they believed, the Megatherium⁠—in 1899, but was no more more succesful that Prichard's later expedition, although a 28 June 1899 report in La Prensa claimed that they had discovered "fresh traces" or "fresh remains" of the Mylodon. Santiago Roth, who had met Cavendish and heard nothing of any fresh traces, thought this unlikely, and doubted that Cavendish had made such a claim. At the same time, Lord Rothschild of the Tring Museum sent out an expedition to the Patagonian forests, led by George Davis and a Scott.

Based on Moreno's hide, Lankester mentioned during a lecture the possibility that Mylodon may still survive in South America: "it is quite possible—I don't want to say more than that—that he still exists in some of the mountainous regions of Patagonia". His statement attracted the attention of newspaper magnate Sir Arthur Pearson, founder of the Daily Express, who despatched the explorer and adventurer Hesketh Vernon Prichard, who had already travelled to Haiti for him, to investigate the matter in Patagonia in 1899. Shortly before leaving England with his second-in-command, J. B. Scrivenor, and three other Europeans, he was joined by an unnamed traveller (sometimes identified as Edward Chace) who "showed good evidence that he knew of very recent tracks" of the Mylodon. One newspaper, The Sphere, was optimistic about his chances, writing "whether the party will capture him [the sloth] in the act of tearing up a tree in the manner of his ancestors or will first sight one being milked by a Tehuelche Indian, only the return of the expedition can say". Prichard's expedition found no evidence, and in the end he concluded that Mylodon was extinct, and all the Patagonian legends referred to a giant otter.

In 1922, naturalist Clement Onelli led an expedition in search of the Patagonian plesiosaur, which he believed was really Ameghino's semi-aquatic Mylodon. The expedition found nothing in the lakes and rivers of Río Negro Province, and was officially called off on 23 April 1923. Onelli died the following year.

In 2001, Charlie Jacoby, the grandson of Hesketh Prichard, and Harvey Carruthers led an expedition to Patagonia to search for evidence of a live ground sloth on the hundred-year anniversary of Prichard's expedition. Jacoby's expedition retraced the route of the first one, but returned equally empty-handed.

Current status

Following the failure of the expeditions, and even moreso after further testing of the hides, the mainstream belief in the possibility of a living Mylodon died down, although numbers of naturalists were open to the possibility until at least 1916, and the idea was revived in 1922 by Clemente Onelli. In On the Track of Unknown Animals (1955), Bernard Heuvelmans questioned whether Patagonia was the right place to look for surviving ground sloths, suggesting instead that they would have been pushed back by human hunting into forested regions such as the Amazon Rainforest and the bosques andinos. Recent reports of ground sloth-like cryptids from the Amazon, such as the mapinguari, segamai, ujea, jucucu, and owhuama, have moved the focus of searches for living ground sloths much further north than Patagonia.

Prichard did not believe that Mylodon still existed, theorising that all the Indian legends of a gigantic quadruped referred to a giant otter, and doubted thant any large animal could live in Patagonia's dense Valdivian forests. However, he admitted that "in addition to the regions visited by our Expedition, there are, as I have said, hundreds and hundreds of square miles about, and on both sides of the Andes, still unpenetrated by man. A large portion of this country is forested, and it would be presumptuous to say that in some hidden valley far beyond the present ken of man some prehistoric animal may not still exist. Patagonia is, however, not only vast, but so full of natural difficulties".

Though his expedition also failed, Clemente Onelli believed that Mylodon still existed in the 1920s. Onelli was convinced that it remained hidden in the lowlands of remote Pacific river valleys of the Andes, "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". He believed it would exist mainly in forest clearings, at altitudes no higher than about 2,600'.

Reconstruction of Mylodon by an unknown artist.

Writing in Abominable Snowmen: Legend Come to Life (1961), Ivan T. Sanderson suggested that some smaller kinds of ground sloth could still exist in Patagonia's uninhabited shrub and brushland areas. Following his own expedition, Charlie Jacoby wrote in 2001 that "there is so much space in the Patagonian forests. Surely there's still a pocket where our creature may still live?" Most recently, a 2006 televised Digging for the Truth investigation involving Jacoby concluded that a species of Mylodon could still exist in Patagonia.

Similar cryptids

Other ground sloth-like cryptids reported from Patagonia include the ellëngassën, the lobo-toro, and the succarath. Although Ameghino thought the iemisch could be a ground sloth, this theory is discounted by cryptozoologists, and served only to confuse the issue of the Patagonian ground sloth. A number of ambiguous quadrupedal animals, including lake bulls and Patagonian tapirs, are also reported from Patagonia, and the fresh tracks of South American short-faced bears were also reported from Patagonia at the end of the 19^th Century. Other South American cryptids speculated to be living ground sloths include the Ecuadorean ground sloth, gran bestia, mapinguari, owhuama, segamai, and possibly the ujea.

In popular culture

• A life-size statue of Mylodon has been erected in the entrance to the Cueva del Milodon, with a larger replica in the nearby city of Puerto Natales. Puerto Natales is also home to a number of smaller replicas of the model, and its image decorates some of the city's street signs.
• A novel featuring the Patagonian ground sloth, In Quest of the Giant Sloth (1902) was written by Gordon Stables very soon after the Prichard expedition and the scientific furore over the Cueva del Milodon skin. The novel also includes a monster very similar to the Patagonian plesiosaur, which was not known at the time.
• The Patagonian Mylodon is also discovered by a pair of explorers in a short story by Elmer Brown Mason, Lost—One Mylodon (1915). Nine of them live in a hidden valley, where they are tended to by a community of Patagonians who remain immortal for as long as the sloths survive. In the story, the only male sloth in the group dies when it runs into a tree during the night.
• The "blonde beast of Patagonia" was one of the cryptids mentioned by Charles Fort in Lo! (1931).
• Charles Amherst Milward took some hide from the Cueva del Milodon and sent it to his cousin, the grandmother of writer Bruce Chatwin. Chatwin's supposed desire to reach the cave in search of either a living animal or a piece of its skin for himself forms the basis of his popular travelogue In Patagonia (1977). In his examination of sightings near the end of the book, Chatwin concludes that the Mylodon is extinct, and that the yaquaru was "probably a caiman".
  • A Werner Herzog documentary based on In Patagonia, Nomad: In the Footsteps of Bruce Chatwin (2019), was produced by BBC Two.
• The Patagonian ground sloth and the cryptids associated with it are mentioned in David Attenborough's documentary and book Fabulous Animals (1975). In the companion book, Attenborough writes that "I don't know if [cryptozoologists] will ever find [a giant sloth], but I would like to be there to make a film of it if they do".
• The plot of the comedy adventure film The Darien Gap (1996) concerns "a twenty-something slacker" who dreams of hitchhiking to Patagonia to film the giant sloth.
• The companion book to the BBC documentary Walking with Beasts (2001) includes the Patagonian giant sloth in a section about alleged prehistoric survivors. However, the sloth in question is incorrectly identified as Megatherium.
• A stuffed "Patagonian giant sloth" plays a major role in the novel Tramps, Beggars and Sloths (2016).

Further cryptozoological reading

• Heuvelmans, Bernard (1955) On the Track of Unknown Animals, Routledge, ISBN 978-1138977525
• Historical resources