HOME | DD

Description
Megatherium americanum

Sloths today are tree-dwelling, sluggish, herbivores who spend their days sleeping and browsing from leaves. The largest extant member of this group of adorable tree-hugging mammals; the two-toed sloth, clocks in at 20lbs. However, 10,000 years ago, a distant cousin of this sloth reached more than 400 times that size. Its name was Megatherium americanum, the giant South American ground sloth.
History:

In 1788, a local prospector named Manuel Torres found a decently complete fossil of an animal on the banks of the Luján River. Unable to identify them and to have no use for them, he shipped them to the museum: Museo Nacional de Ciencias Naturales in Madrid the following year.

There, Juan Bautista Bru, a museum employee, reconstructed the animal. It was finally revealed to the public in 1795. This was the first mounted skeleton of any extinct animal mounted for public viewing.

It can still be seen today, albeit in a corrected manner. Bru lacked the hands of the animal, so he sculpted them based on the feet. In terms of size, the animal was likely a juvenile as it was nowhere near the size of other specimens of Megatherium.

When it was unveiled, there was no name given to this organism, so the museum contacted the foremost anatomist in the world at the time, Georges Cuvier. Cuvier realized that this animal was a sloth from comparing bones to modern animals. However, he posited that this animal likely used its claws to dig for roots underground and probably dwelt in subterranean caves. An observation that wouldn't be far off, as will be discussed later.

Cuvier dubbed the animal: Megatherium americanum, the name derived from the Greek, méga meaning "great" and theríon meaning "beast." The specific name is a Latinized word for America. So "America's Great Beast".

Several other species have been described with fragmentary and complete remains in the intervening years. However, the most complete remains the type species as described in this profile.

Taxonomy:

Sloths are members of the superorder Xenarthra. This group includes animals such as sloths, anteaters, and armadillos. Sloths are members of the Pilosa order which means "hairy ones". DNA analysis indicates that these animals are a sister lineage to anteaters diverging around 40,000,000 years ago. What they looked like before this is unknown, as fossils from this time are rare, and the origin of xenarthrans is somewhat enigmatic.

Regarding relations, the most recent studies place Megatherium and its clade within the superfamily Megatherioidea. This group includes other ground sloths such as Megalonychids with animals like the widespread Jefferson Ground Sloth. However, the closest relatives would be Nothrotheriidae which includes animals like the Shasta Ground Sloth.

Megatheres themselves would have evolved some 25,000,000 years ago in Argentina. At first, they would have been small, with animals like the Hapalops being present during the early Miocene. However, other animals like Prepotherium, the size of bison, also arose at this time. Moreover, the genus Proeremotherium would appear at the end of the Miocene, and it's believed that this lineage would give rise to Megatherium.

Various species have been described and the genus arose in the early Pliocene. A trend that has observed was that these species increase in size as the Pliocene goes on. The largest and last species would be Megatherium americanum arising in the Mid-Pleistocene some 400,000 years ago.

Ironically, included in this superfamily of Megatherioidea is the two-toed sloth of the genus Bradypus, which consists of the most miniature sloth. The endangered pygmy two-toed sloth dwells on an island off Panama, which was 1750 times smaller than the average Megatherium americanum.

Description:

Megatherium was a massive animal. Weighing over four tons, 18-20ft long, and around 6ft tall at the shoulder, it would have been the largest mammal in South America along with Eremotherium until the Great American Interchange when proboscideans like Notiomastodon and Stegomastodon arrived in South America.

A typical ground sloth body plan but scaled up. A bulky body, robust limbs and claw-tipped feet and forefeet for defense, locomotion and of course, browsing from trees. The body weight of this giant sloth is believed to have been around 4 tons around the size of a female bush elephant of Africa.

Analysis of its hyoid bone indicates Megatherium would have likely had a tongue that was long and flexible and designed to assist in feeding. When it reared up, it would have stood in excess of 12ft tall. Similar to giraffes of today. It is fitting, given the niche that it would have occupied in the Americas Its skull would have been shortened compared to other ground sloths with massive molars designed to process vast amounts of vegetation.

Megatherium had a strange hand structure. Like most ground sloths, it had robust forelimbs tipped with claws designed to pull foliage towards it and for defense from predation. Digit one was buried and probably not visible from the surface. Digits two and three had the massive claws, while four and five had stubby nails.

Hair or no hair?:

Recent debates have been had through the past two decades on if Megatherium was hairy or naked in terms body covering. With some paleontologists believing the large body size of megatheres such as Eremotherium and Megatherium would prevent it from growing large amounts of hair. However, given the environment of Megatherium, being the western part of South America with regions of the Pampas, Patagonia, and Chile was cold and had some snow on occasion. This would probably have meant it'd need to keep its insulation. Furthermore, Sloths overall have a lower metabolism than warm blooded mammals. This means they would loose heat faster than most mammals.

As of today, there are studies underway to determine if the metabolism played a role in retaining body hair for larger ground sloths in excess of 2 tons.

Behavior:

Analysis of their teeth indicate that this animal was a particular browser feeding on leaves and fruit in Western South America. The animal had both a prehensile lip designed to snag foliage moreover, as previously mentioned, the animal probably had a tongue designed to grasp vegetation in a manner like the giraffe and okapi of today.

Some paleontologists have suggested that this animal would have used its massive size to scare away animals like jaguars and the extinct saber-toothed cat, Smilodon away from kills and have eaten carrion to supplement its diet.

This was shown in the program Walking With Beasts. However, analysis of the bone collagen analysis indicates that there is no evidence of carrion behavior. Furthermore, with no incisors, paleontologists such as the late Paul Martin have described this as "fanciful". However, a distant cousin, Mylodon does show evidence of scavenging behavior, furthermore, modern-day sloths will occasionally eat insects and small vertebrates on occasion, so it's not out of the question.

Though quadruped, trackways found in South America indicate an animal of similar size being able to walk bipedally. While not likely its preferred mode of locomotion the trackways show these animals would at least have been competent bipedal walkers.

No baby animals have been found so their rearing habits are unknown. However, given the size it could be presumed that Megatherium had long gestation periods. By observing the only extant terrestrial pilosan, the Giant Anteater, it's possible that ground sloths like Megatherium would have carried their baby on their back.

Some ground sloths in the fossil record have also been found together, suggesting herding behavior. However, it should be noted no megatheres have been found together. So while not out of the question, it's assumed that these animals may have been solitary.

While Cuvier proposal that this animal was subterranean was farfetched, there is some evidence that Megatherium and its kin have dwelt in burrows and caves. Perhaps using this as shelter from the elements of the Pampas plains. Furthermore, with its massive claws it could have hollowed out burrows more effectively than other animals.

Habitat:

Megatherium's habitat would have been a mix of scrub forests, open Pampas grasslands and scattered woodland. It should be noted that these animals have been primarily centralized in the Pampas.

Fossils of this animal have been found across Argentina, Bolivia and Chile. Animals living alongside it would have been various species of sloths such as Mylodon and Scelidotherium. Alongside their fellow sloths would have been the small horse, Hippidion, the glyptodonts Doedicurus and Glyptodon, notoungulates like Macrauchenia, Xenorhinotherium, and the rhino-like Toxodon. More recent arrivals would be animals like Cuvieronius and Notiomastodon, two species of gomphothere proboscideans.

Fully grown, healthy adults would have no enemies; however, juveniles would have been vulnerable to animals like Smilodon fatalis in northern regions of South America and S. populator throughout the rest of its range. Jaguars like the Pleistocene Jaguars were present in this range too.

Extinction:

The extinction of this massive sloth is believed to have been around 10,000 years ago. However, fragments of bone attributable to Megatherium have been dated to about 8,000 years, though these are controversial. The cause of the extinction is unknown, but most hypotheses appear to land on being due to climate change as well as overhunting by humans.

A fossil find in the Pampas region of Argentina called Campo Laborde has had a specimen of Megatherium americanum with evidence of butchery. Alongside the bones were stone tools that matched striations found on the bones. Other animals like Doedicurus, the club-tailed glyptodont, have also been butchered at this site. It's possible that these animals were ambushed and speared to death by tribes of humans in South America.

With the extinction of these ground sloths and the notoungulates, South America has lost some of its most iconic land mammals. Now, all that remains are the tree-dwelling sloths in the montane and tropical rainforests throughout South and Central America. Now, all that remain are fossils of these animals. A reminder of South America's bizarre and awe-inspiring past.

___________________________________________________________________________________________

Ahh... the iconic Megatherium. One of my favorite South American land mammals. An animal that is a staple of many museum exhibits including one in my home town.

I did have an old draft of this guy ready from last year, but decided to get this one redone, mainly because the hands were rather inaccurate. I'll tell you, getting the hands right, while I had good references from both my own photos and online, getting them right in 3D was difficult. Especially the baby, however, forgivably, I finally got it right.

It's funny, because this guy isn't going to be in PMP, but I stressed over the hands so much. Furthermore, I should add, while this guy won't be in PMP, its cousin will. Which I will have a redone profile soon.

Hope you guys enjoy this profile and have a stellar weekend!

UPDATE: Okay, thanks to some input through artbyjrc I had to redo the hands. Though honestly, I'm glad I did, it allowed me to redo both the adult and the baby model properly. So thanks a ton my friend. Got it done and set. Due to limitations with the models, I couldn't get 5 digits.

Here's the old model if you're curious:
i.imgur.com/3ameNoa.jpg

Skins and Models made from Lgcfm and Ulquiorra's Megatherium respectively. Model modified by me.
Giant Ground Sloth (Lgcfm & Ulquiorra) | ZT2 Download Library Wiki | Fandom

Description
Megatherium americanum

Sloths today are tree-dwelling, sluggish, herbivores who spend their days sleeping and browsing from leaves. The largest extant member of this group of adorable tree-hugging mammals; the two-toed sloth, clocks in at 20lbs. However, 10,000 years ago, a distant cousin of this sloth reached more than 400 times that size. Its name was Megatherium americanum, the giant South American ground sloth.
History:

In 1788, a local prospector named Manuel Torres found a decently complete fossil of an animal on the banks of the Luján River. Unable to identify them and to have no use for them, he shipped them to the museum: Museo Nacional de Ciencias Naturales in Madrid the following year.

There, Juan Bautista Bru, a museum employee, reconstructed the animal. It was finally revealed to the public in 1795. This was the first mounted skeleton of any extinct animal mounted for public viewing.

It can still be seen today, albeit in a corrected manner. Bru lacked the hands of the animal, so he sculpted them based on the feet. In terms of size, the animal was likely a juvenile as it was nowhere near the size of other specimens of Megatherium.

When it was unveiled, there was no name given to this organism, so the museum contacted the foremost anatomist in the world at the time, Georges Cuvier. Cuvier realized that this animal was a sloth from comparing bones to modern animals. However, he posited that this animal likely used its claws to dig for roots underground and probably dwelt in subterranean caves. An observation that wouldn't be far off, as will be discussed later.

Cuvier dubbed the animal: Megatherium americanum, the name derived from the Greek, méga meaning "great" and theríon meaning "beast." The specific name is a Latinized word for America. So "America's Great Beast".

Several other species have been described with fragmentary and complete remains in the intervening years. However, the most complete remains the type species as described in this profile.

Taxonomy:

Sloths are members of the superorder Xenarthra. This group includes animals such as sloths, anteaters, and armadillos. Sloths are members of the Pilosa order which means "hairy ones". DNA analysis indicates that these animals are a sister lineage to anteaters diverging around 40,000,000 years ago. What they looked like before this is unknown, as fossils from this time are rare, and the origin of xenarthrans is somewhat enigmatic.

Regarding relations, the most recent studies place Megatherium and its clade within the superfamily Megatherioidea. This group includes other ground sloths such as Megalonychids with animals like the widespread Jefferson Ground Sloth. However, the closest relatives would be Nothrotheriidae which includes animals like the Shasta Ground Sloth.

Megatheres themselves would have evolved some 25,000,000 years ago in Argentina. At first, they would have been small, with animals like the Hapalops being present during the early Miocene. However, other animals like Prepotherium, the size of bison, also arose at this time. Moreover, the genus Proeremotherium would appear at the end of the Miocene, and it's believed that this lineage would give rise to Megatherium.

Various species have been described and the genus arose in the early Pliocene. A trend that has observed was that these species increase in size as the Pliocene goes on. The largest and last species would be Megatherium americanum arising in the Mid-Pleistocene some 400,000 years ago.

Ironically, included in this superfamily of Megatherioidea is the two-toed sloth of the genus Bradypus, which consists of the most miniature sloth. The endangered pygmy two-toed sloth dwells on an island off Panama, which was 1750 times smaller than the average Megatherium americanum.

Description:

Megatherium was a massive animal. Weighing over four tons, 18-20ft long, and around 6ft tall at the shoulder, it would have been the largest mammal in South America along with Eremotherium until the Great American Interchange when proboscideans like Notiomastodon and Stegomastodon arrived in South America.

A typical ground sloth body plan but scaled up. A bulky body, robust limbs and claw-tipped feet and forefeet for defense, locomotion and of course, browsing from trees. The body weight of this giant sloth is believed to have been around 4 tons around the size of a female bush elephant of Africa.

Analysis of its hyoid bone indicates Megatherium would have likely had a tongue that was long and flexible and designed to assist in feeding. When it reared up, it would have stood in excess of 12ft tall. Similar to giraffes of today. It is fitting, given the niche that it would have occupied in the Americas Its skull would have been shortened compared to other ground sloths with massive molars designed to process vast amounts of vegetation.

Megatherium had a strange hand structure. Like most ground sloths, it had robust forelimbs tipped with claws designed to pull foliage towards it and for defense from predation. Digit one was buried and probably not visible from the surface. Digits two and three had the massive claws, while four and five had stubby nails.

Hair or no hair?:

Recent debates have been had through the past two decades on if Megatherium was hairy or naked in terms body covering. With some paleontologists believing the large body size of megatheres such as Eremotherium and Megatherium would prevent it from growing large amounts of hair. However, given the environment of Megatherium, being the western part of South America with regions of the Pampas, Patagonia, and Chile was cold and had some snow on occasion. This would probably have meant it'd need to keep its insulation. Furthermore, Sloths overall have a lower metabolism than warm blooded mammals. This means they would loose heat faster than most mammals.

As of today, there are studies underway to determine if the metabolism played a role in retaining body hair for larger ground sloths in excess of 2 tons.

Behavior:

Analysis of their teeth indicate that this animal was a particular browser feeding on leaves and fruit in Western South America. The animal had both a prehensile lip designed to snag foliage moreover, as previously mentioned, the animal probably had a tongue designed to grasp vegetation in a manner like the giraffe and okapi of today.

Some paleontologists have suggested that this animal would have used its massive size to scare away animals like jaguars and the extinct saber-toothed cat, Smilodon away from kills and have eaten carrion to supplement its diet.

This was shown in the program Walking With Beasts. However, analysis of the bone collagen analysis indicates that there is no evidence of carrion behavior. Furthermore, with no incisors, paleontologists such as the late Paul Martin have described this as "fanciful". However, a distant cousin, Mylodon does show evidence of scavenging behavior, furthermore, modern-day sloths will occasionally eat insects and small vertebrates on occasion, so it's not out of the question.

Though quadruped, trackways found in South America indicate an animal of similar size being able to walk bipedally. While not likely its preferred mode of locomotion the trackways show these animals would at least have been competent bipedal walkers.

No baby animals have been found so their rearing habits are unknown. However, given the size it could be presumed that Megatherium had long gestation periods. By observing the only extant terrestrial pilosan, the Giant Anteater, it's possible that ground sloths like Megatherium would have carried their baby on their back.

Some ground sloths in the fossil record have also been found together, suggesting herding behavior. However, it should be noted no megatheres have been found together. So while not out of the question, it's assumed that these animals may have been solitary.

While Cuvier proposal that this animal was subterranean was farfetched, there is some evidence that Megatherium and its kin have dwelt in burrows and caves. Perhaps using this as shelter from the elements of the Pampas plains. Furthermore, with its massive claws it could have hollowed out burrows more effectively than other animals.

Habitat:

Megatherium's habitat would have been a mix of scrub forests, open Pampas grasslands and scattered woodland. It should be noted that these animals have been primarily centralized in the Pampas.

Fossils of this animal have been found across Argentina, Bolivia and Chile. Animals living alongside it would have been various species of sloths such as Mylodon and Scelidotherium. Alongside their fellow sloths would have been the small horse, Hippidion, the glyptodonts Doedicurus and Glyptodon, notoungulates like Macrauchenia, Xenorhinotherium, and the rhino-like Toxodon. More recent arrivals would be animals like Cuvieronius and Notiomastodon, two species of gomphothere proboscideans.

Fully grown, healthy adults would have no enemies; however, juveniles would have been vulnerable to animals like Smilodon fatalis in northern regions of South America and S. populator throughout the rest of its range. Jaguars like the Pleistocene Jaguars were present in this range too.

Extinction:

The extinction of this massive sloth is believed to have been around 10,000 years ago. However, fragments of bone attributable to Megatherium have been dated to about 8,000 years, though these are controversial. The cause of the extinction is unknown, but most hypotheses appear to land on being due to climate change as well as overhunting by humans.

A fossil find in the Pampas region of Argentina called Campo Laborde has had a specimen of Megatherium americanum with evidence of butchery. Alongside the bones were stone tools that matched striations found on the bones. Other animals like Doedicurus, the club-tailed glyptodont, have also been butchered at this site. It's possible that these animals were ambushed and speared to death by tribes of humans in South America.

With the extinction of these ground sloths and the notoungulates, South America has lost some of its most iconic land mammals. Now, all that remains are the tree-dwelling sloths in the montane and tropical rainforests throughout South and Central America. Now, all that remain are fossils of these animals. A reminder of South America's bizarre and awe-inspiring past.

___________________________________________________________________________________________

Ahh... the iconic Megatherium. One of my favorite South American land mammals. An animal that is a staple of many museum exhibits including one in my home town.

I did have an old draft of this guy ready from last year, but decided to get this one redone, mainly because the hands were rather inaccurate. I'll tell you, getting the hands right, while I had good references from both my own photos and online, getting them right in 3D was difficult. Especially the baby, however, forgivably, I finally got it right.

It's funny, because this guy isn't going to be in PMP, but I stressed over the hands so much. Furthermore, I should add, while this guy won't be in PMP, its cousin will. Which I will have a redone profile soon.

Hope you guys enjoy this profile and have a stellar weekend!

UPDATE: Okay, thanks to some input through artbyjrc I had to redo the hands. Though honestly, I'm glad I did, it allowed me to redo both the adult and the baby model properly. So thanks a ton my friend. Got it done and set. Due to limitations with the models, I couldn't get 5 digits.

Here's the old model if you're curious:
i.imgur.com/3ameNoa.jpg

Skins and Models made from Lgcfm and Ulquiorra's Megatherium respectively. Model modified by me.
Giant Ground Sloth (Lgcfm & Ulquiorra) | ZT2 Download Library Wiki | Fandom