The Peaceful tooth, Mylodon (1840)

Phylum : Chordata
Class : Mammalia
Superorder : Xenarthra
Order : Pilosa
Family : Mylodontidae
Subfamily : Mylodontinae
Genus : Mylodon
Species : M. darwini

  • Pleistocene/Holocene
  • 3 m long and 200 kg (size)
  • Buenos aires province, Argentina (map)

Mylodon’s close relatives include the giant ground sloths of the genera Glossotherium and Paramylodon. The latter genus has often been confused with Glossotherium but Paramylodon is a distinct genus that was restricted to the Pleistocene of North America. Glossotherium also shares a long history of taxonomic confusion with Mylodon, and currently the only recognized species is Mylodon darwinii. At one time, the elephant-sized Megatherium was thought to be closely related, but is recognized as belonging to a separate family (Megatheriidae).

Mylodon has been traditionally considered a grazer in open areas, which is theorized based on its paleoenvironment as well as from the vegetation found in fossilized dung. However, recent studies based on biomechanics and functional morphology indicate that Mylodon may have been a mixed or selective-feeder instead, and the paleoenvironment of the formation where the animal was found indicates a wide variety of vegetation to be selected from.

A variety of specimens found throughout Argentina and Chile indicate that Mylodon had a wide range of climatic and environmental tolerance. It was probably capable of inhabiting arid to semiarid and cold climates, humid and warm climates, and colder and montane climates.


Is the legendary Mapinguari a giant ground sloth?

The first rumours that a giant ground sloth species may still exist reached Europe in the 16th century. Sailors brought home stories of “water tigers” backed up by fossil bones.

In 1789, Dr. Bartolome de Muñoz found Megatherium bones near what is now Buenos Aires. He gave them to the King of Spain, prompting the King to order a complete specimen of the animal alive or dead.

The rumours gained more credence in the late 19th century. The future governor of Santa Cruz province in southern Patagonia, Ramón Lista, was riding in Santa Cruz in the late 1880s when a shaggy red-haired beast resembling what he called a “giant pangolin” trotted across his path. He had time to loose off several rounds from his rifle before it disappeared into the scrub, and was amazed to note that they bounced off the animal’s hide. Lista only gave a verbal account of this story, to an animal collector called Carlos Ameghino, who told his brother Florentino Ameghino, who was one of Argentina’s most notable naturalists and later the vice-director and secretary of the best natural history museum in South America, La Plata, which opened in 1888 outside Buenos Aires.

The following is from Wikipedia:

The mapinguari is a legendary cryptid said to resemble a ground sloth–like creature with red fur living in the Amazon rainforests of Brazil and Bolivia. The name is usually translated as “the roaring animal” or “the fetid beast”.


According to native folklore the creature has a series of unnatural characteristics related to other fantastic beings of Brazilian mythology. These include the creature only having one eye, long claws, caiman skin, backward feet and a second mouth on its belly. In more recent eyewitness accounts it has consistently been described as resembling either an ape or giant ground-dwelling sloth and having long arms, powerful claws that could tear apart palm trees, a sloping back, reaching heights of 7 feet when standing on its hind legs and is covered in thick, matted fur.

Habits and abilities

According to legend, it is slow but ferocious and very dangerous due to its ability to move without noise in the thick vegetation, surprising the unsuspecting locals. Accounts state that it gave off a putrid stench and emitted a frightening shriek, and that weapons such arrows and bullets could not penetrate the Mapinguari’s alligator-like hide. Its only known weakness is that it avoids bodies of water, which limits its movements in a region where so many rivers, brooklets and lagoons exist (especially during the rainy season). It was believed to be carnivorous, as a 1937 report from central Brazil claimed a mapinguari had gone on a three-week rampage, killing over 100 cows and ripping out the tongues from their carcasses. However, in all accounts it did not eat humans, although when it smells the presence of people it stands up on its back feet, becoming as tall as two metres, a movement similar to grizzly bears.


Many cryptozoologists are intrigued by reports of this creature, though some have dismissed it as a folkloric/mythologic creature, or a long-preserved folk memory of the giant animals that existed in South America in the Pleistocene. Theories of the identity of the mapinguari have suggested that it was a giant primate, a giant ground sloth (most likely Mylodon), or possibly even an unusual giant anteater, perhaps Myrmecophaga tridactyla. The ground-sloth theory can provide an explanation for its supposed bulletproof hide, as preserved ancient skin samples in the late 19th century revealed hard dermal ossicles, small pieces of bone in the skin of dinosaurs and alligators that protected them from predators. It is possible that such skin would have been impervious to arrows and bullets.

Despite several efforts, searches for verifiable physical evidence have been futile, as the only evidence for the existence of the mapinguari is anecdotal. Among the many researchers who have tried to find evidence for the existence of the mapinguari is the ornithologist David Oren. During his various expeditions, he has collected a range of material some of which was later shown to be agouti fur, anteater feces, and casts of tracks that were inconclusive. Nevertheless, Oren still considers the creature to be real, but highly elusive, and nowadays extremely rare, avoiding contact with humans whenever possible.

From Frontiers of Zoology:

Cryptozoologist David Oren made the assertion that the Mapinguari represented the Brazillian version of the surviving ground sloth. In this he seems to have been mistaken because the Mapinguari is tailless. The groundsloth would also not be leaving the “Cup-shaped” Pe-de-Garaffa tracks, and it seems that that is what the name “Mapinguari” origiinally meant. However, the creature called “Wolfhide” apparently had a tail and an elongated snout, shown as an anteater’s snout on one of the representations earlier, a probable confusion between the two types.

There are several regional names for Mapinguari and sometimes the direct reference is confused or obscure. However, on this blog, I have made the distinction that the “Bottlefoot” is one kind of creature, a large tailless ape sometimes said to be a cyclops and to have no discernable head, only a distinctive mouth part with sharp teeth arising from the torso (basically an illusion brought about by having confusing, Orangutan-like anatomy) while the “:Wolfskin” is another, same as the Lobo-Toro, same as the “living Groundsloths” observed in Equador-and incidentally as “Cave Cows” in Belize as reported by Ivan Sanderson, possibly even with a representative that lives on Cuba. There are also two lesser groundsloths rumored around the Caribbean: one about the size of a medium-sized bear and the other the size of a small ape or chimp, both called “Yehos” or “Yahus” (“Devils) and with large hooked claws. Three or four species of Ground sloth are known to have survived up until the European colonial period in the Greater Antilles.

Lista, had been commissioned by the Argentine government to explore the unknown recesses of Patagonia during the border dispute that was then raging with Chile. He was a friend of Argentinian Naturalists Moreno and Ameghino. Ameghino said that Lista had told him, his brother and others (verbally, yet he believed that he had also written about it) that once, while riding in the interior of the Patagonian territory of Santa Cruz, he had seen “and shot at a mysterious creature […] apparently bullet-proof, it disappeared into the brushwood, and all search for it proved futile”. Lista described the creature as a pangolin, without scales, and “covered with reddish grey hair”.

In Lista’s words -as quoted by Ameghino- 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. Ameghino, apparently based on his own brother’s (Carlos) reports, wrote that he had heard on many occasions allusions to 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.”

Ameghino also said that at first he was puzzled by the description that Lista gave of his pangolin and unsuccessfully tried to identify the animal. When he finally got a piece of the “Neomylodon” skin from his brother, he had no doubts that Lista’s pangolin was a variety of mylodon. Its smaller ossicles implied that it was a smaller species.

There is no doubt however that the surviving giant ground sloths are NOT the same as the Mapinguari even if we are not concerned with the presence or absence of a long and thick heavy tail like a kangaroo’s tail (something which would seem to be hard to miss). The difference is in the shoulder region: Mapinguari has the shoulder joint of a brachiating ape and has no trouble raising its arms high above its head. The ground sloths do NOT have this type of shoulder and hence their range of arm movement is considerably more limited.

But even without equating the two, there is still reason to suggest there is a persisting species of Mylodon-like groundsloth in the Amazon rainforests as well as other areas, and that is otherwise much like the groundsloths found in the La Brea Tar Pits.

And it would be a herbivore, not a carnivore, unless it could also take carrion as an appetizer. It is noted to have an elongated snout like a horse or a wolf’s and the Native informants always make a big deal of the large hooked claws (dyed red with the blood of their victims, in the more lurid accounts, which is NOT something that turns up in stories about the Mapinguari)

In popular culture

A March 2011 episode of Beast Hunter titled “Nightmare of the Amazon” aired on the National Geographic Channel, featuring a search for mapinguari in the Amazon Basin.

Josh Gates, world adventurer and eager truth-seeker, headed to the rainforests of Brazil in search of the legendary Mapinguary, for his Destination Truth show season two, trailing recent sightings of a giant sloth monster and finding reports that it might be a descendant of the giant sloth, a species long thought to be extinct. You can watch the Sloth Monster episode instantly at for a couple bucks. The video also shows Josh Gates going to Africa in search of a flying dinosaur that has reportedly been harassing the locals from overhead.

"En Invierno, el Milodón nunca sale de su cueva, prefiere dormir largas siestas y olvidarse del frío. Cuando decide salir de ella para buscar algo de comida y relacionarse con otros Milodones, se encuentra con un nevado paisaje magallánico que le da vida a su extinta alma." 

Foto tomada a las afueras de la Cueva del Milodón, Región de Magallanes y la Antártica Chilena, Chile.


Day 2: First day touring Patagonia: Milodon Caves:

The first stop on our private tour with our small group was the Milodon Cave. This cave is famous for the findings of the skin, hair, and bone findings of a sloth called the Mylodon that existed 13,000 years before. 

Can you imagine?? 13,000 YEARS! Walking up to the cave you can completely imagine dinosaurs and prehistoric animals roaming around here. its’ like nothing is changed except for a walkway and a few informational signs and maps. Here they have a lifesize sculpture of the Mylodon, we think it looks like a cute bear :) It was a pretty cool start to the tour. 

Eulogy to The Mylodon

by Thomas Watkins

Heavier than a bull and taller than an upright polar bear, the Mylodon roamed the plains of Patagonia for millennia. Leaning against its thick long tail for support, it stood on its hind legs and reached high into trees for berries and leaves. Around it galloped herds of tiny horses, native to south America. The Mylodon, with thick, ossified scaly skin had no natural predators. Man arrived, via the Bering Strait then down through the continent, about 10,000 years ago. The animals he encountered, including the Mylodon and the horses, had evolved with no fear of this naked ape. Within only a few centuries of his arrival, the Mylodon, the horses and other Patagonian creatures were gone.