Ground sloth
Encyclopedia
Ground sloths are a diverse group of extinct sloth
s, in the mammal
ian superorder Xenarthra
. Their most recent survivors lived in the Antilles
, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS
radiocarbon
date reported is 4190 BP
, calibrated to c. 4700 BP for Megalocnus
of Cuba
. They had been extinct on the mainland of North
and South America
for 10,000 years or more. The term "ground sloth" is used as a reference for all extinct sloths because of the large size of the earliest forms discovered, as opposed to the extant "tree sloths." However, this is a historical convention and does not imply that all extinct sloths were strictly terrestrial
in nature.
The bulk of ground sloth evolution took place during the mid to late Tertiary of South America while the continent was isolated. At their earliest appearance in the fossil record, the ground sloths are already distinct at the family level. The presence of intervening islands between the American continents in the Miocene
allowed a dispersal of forms into North America. A number of mid- to small-sized forms are believed to have previously dispersed to the Antilles
islands either by making short swims or using land bridges that are now submerged. Ground sloths were a hardy group as evidenced by their diverse numbers and dispersals into remote areas given the finding of their remains in Patagonia (Cueva del Milodón) and parts of Alaska
.
Sloths, and xenarthrans as a whole, represent one of the more successful South American groups during the Great American Biotic Interchange
. During the interchange, many more taxa moved from North America into South America than in the other direction. At least five genera of ground sloths have been identified in North American fossils; these are examples of successful immigration to the north.
of ground sloths in multiple families
.
The megalonychid ground sloths first appeared in the early Oligocene
, about 35 million years ago, in southern Argentina (Patagonia
). Megalonychids first reached North America by island-hopping, prior to the formation of the Isthmus of Panama
. Some lineages of megalonychids increased in size as time progressed. The first species of these were small and may have been partly tree-dwelling, whereas the Pliocene
(about 5 to 2 million years ago) species were already approximately half the size of the huge Late Pleistocene
Megalonyx jeffersonii
from the last ice age. Some West Indian island species were as small as a large cat; their dwarf condition typified both tropical adaptation and their restricted island environment. This small size also enabled them a degree of aboreality.
Megalonyx
, which means "giant claw" is a widespread North American genus, lived past the close of the last (Wisconsin) glaciation, when so many large mammals died out. Remains have been found as far north as Alaska
and the Yukon
. Ongoing excavations at Tarkio Valley in southwest Iowa may reveal something of the familial life of Megalonyx. An adult was found in direct association with two juveniles of different ages, suggesting that adults cared for young of different generations.
The earliest known North America
n megalonychid, Pliometanastes protistus, lived in Florida
and the southern U.S. about 9 million years ago, and is believed to have been the predecessor of Megalonyx. Several species of Megalonyx
have been named; in fact it has been stated that "nearly every good specimen has been described as a different species". A broader perspective on the group, accounting for age, sex, individual and geographic differences, indicates that only three species are valid (M. leptostomus, M. wheatleyi, and M. jeffersonii) in the late Pliocene and Pleistocene of North America. Although work by McDonald lists five species.
Jefferson's ground sloth has a special place in modern paleontology
, for Thomas Jefferson
's letter on Megalonyx, read before the American Philosophical Society
of Philadelphia, in August 1796, marked the beginning of vertebrate
paleontology in North America. When Lewis and Clark set out, Jefferson instructed Meriwether Lewis to keep an eye out for ground sloths. He was hoping they would find some living in the Western range. Megalonyx jeffersonii was appropriately named after Thomas Jefferson.
The megatheriid ground sloths are relatives of the megalonychids; these two families, along with the family Nothrotheriidae (see below), form the infraorder Megatheria. Megatheriids appeared later in the Oligocene, some 30 million years ago, also in South America. The group includes the heavily-built Megatherium
(given its name 'great beast' by Georges Cuvier
) and Eremotherium
. The skeletal structure of these ground sloths indicates that the animals were massive. Their thick bones and even thicker joints (especially those on the hind legs) gave their appendages tremendous power that, combined with their size and fearsome claws, provided a formidable defense against predators.
The earliest megatheriid in North America was Eremotherium eomigrans which arrived 2.2 million years ago, after crossing the recently formed Panama
nian land bridge. With more than five tons in weight, 6 meters in length, and able to reach as high as 17 feet (5.2 m), it was taller than an African Bush Elephant
bull. Unlike relatives, this species retained a plesiomorphic extra claw. While other species of Eremotherium had four fingers with only two or three claws, E. eomigrans had five fingers, four of them with claws up to nearly a foot long.
, and together the two form the superfamily Megatheroidea. The most prominent members of the group are the South American genus Thalassocnus
, known for being aquatic, and Nothrotheriops
from North America
.
The last ground sloths in North America belonging to Nothrotheriops died so recently that their petrified dung (coprolite
s) has remained undisturbed in some caves, as if it were just recently deposited. One of the skeletons, found in a lava tube
(cave) at Aden Crater
, adjacent to Kilbourne Hole
, New Mexico
, still had skin and hair preserved, and is now at the Yale Peabody Museum. The American Museum of Natural History
in New York City has a sample of dung with a note attached to it that reads "deposited by Theodore Roosevelt
". The largest samples of Nothrotheriops dung can be found in the collections of the Smithsonian Museum.
The mylodontid ground sloths together with their relatives the scelidotheriids and the orophodontids form the Mylodonta, the second radiation of ground sloths. The discovery of their fossils in caverns associated with human occupation lead some early researchers to theorize that the early humans built corral
s when they could procure a young ground sloth, to raise the animal to butchering size. However, radiocarbon dates
do not support simultaneous occupation of the site by humans and sloths. Subfossil
remains like coproliths, fur and skin have been discovered in some quantities.
Orophodontoidea, the sister taxon to the Mylodontoidea.
often identify the mapinguari
, a mythical forest creature of the upper Amazon basin
, with a surviving tropical ground sloth or folk memory
of these animals.
Sloth
Sloths are the six species of medium-sized mammals belonging to the families Megalonychidae and Bradypodidae , part of the order Pilosa and therefore related to armadillos and anteaters, which sport a similar set of specialized claws.They are arboreal residents of the jungles of Central and South...
s, in the mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
ian superorder Xenarthra
Xenarthra
The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...
. Their most recent survivors lived in the Antilles
Antilles
The Antilles islands form the greater part of the West Indies in the Caribbean Sea. The Antilles are divided into two major groups: the "Greater Antilles" to the north and west, including the larger islands of Cuba, Jamaica, Hispaniola , and Puerto Rico; and the smaller "Lesser Antilles" on the...
, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS
Accelerator mass spectrometry
Accelerator mass spectrometry differs from other forms of mass spectrometry in that it accelerates ions to extraordinarily high kinetic energies before mass analysis. The special strength of AMS among the mass spectrometric methods is its power to separate a rare isotope from an abundant...
radiocarbon
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
date reported is 4190 BP
Before Present
Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...
, calibrated to c. 4700 BP for Megalocnus
Megalocnus
The ground sloths of the extinct genus Megalocnus were among the largest of the Caribbean ground sloths, with individuals estimated to have weighed up to when alive. Two species are known, M. rodens of Cuba, and M. zile of Hispaniola. Subfossils of M...
of Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
. They had been extinct on the mainland of North
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
for 10,000 years or more. The term "ground sloth" is used as a reference for all extinct sloths because of the large size of the earliest forms discovered, as opposed to the extant "tree sloths." However, this is a historical convention and does not imply that all extinct sloths were strictly terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
in nature.
The bulk of ground sloth evolution took place during the mid to late Tertiary of South America while the continent was isolated. At their earliest appearance in the fossil record, the ground sloths are already distinct at the family level. The presence of intervening islands between the American continents in the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
allowed a dispersal of forms into North America. A number of mid- to small-sized forms are believed to have previously dispersed to the Antilles
Antilles
The Antilles islands form the greater part of the West Indies in the Caribbean Sea. The Antilles are divided into two major groups: the "Greater Antilles" to the north and west, including the larger islands of Cuba, Jamaica, Hispaniola , and Puerto Rico; and the smaller "Lesser Antilles" on the...
islands either by making short swims or using land bridges that are now submerged. Ground sloths were a hardy group as evidenced by their diverse numbers and dispersals into remote areas given the finding of their remains in Patagonia (Cueva del Milodón) and parts of Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
.
Sloths, and xenarthrans as a whole, represent one of the more successful South American groups during the Great American Biotic Interchange
Great American Interchange
The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...
. During the interchange, many more taxa moved from North America into South America than in the other direction. At least five genera of ground sloths have been identified in North American fossils; these are examples of successful immigration to the north.
Families
Paleontologists divide more than 80 generaGenera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
of ground sloths in multiple families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
.
Megalonychidae
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
, about 35 million years ago, in southern Argentina (Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
). Megalonychids first reached North America by island-hopping, prior to the formation of the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...
. Some lineages of megalonychids increased in size as time progressed. The first species of these were small and may have been partly tree-dwelling, whereas the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
(about 5 to 2 million years ago) species were already approximately half the size of the huge Late Pleistocene
Late Pleistocene
The Late Pleistocene is a stage of the Pleistocene Epoch. The beginning of the stage is defined by the base of the Eemian interglacial phase before the final glacial episode of the Pleistocene 126,000 ± 5,000 years ago. The end of the stage is defined exactly at 10,000 Carbon-14 years BP...
Megalonyx jeffersonii
Megalonyx jeffersonii
Megalonyx jeffersonii, or Jefferson's ground sloth, is an extinct species of giant ground sloth that lived from the Illinoian Stage during the Middle Pleistocene through to the Rancholabrean of the Late Pleistocene . Its closest living relatives are the two-toed tree sloths of the genus...
from the last ice age. Some West Indian island species were as small as a large cat; their dwarf condition typified both tropical adaptation and their restricted island environment. This small size also enabled them a degree of aboreality.
Megalonyx
Megalonyx
Megalonyx is an extinct genus of giant ground sloths of the family Megalonychidae endemic to North America from the Hemphillian of the Late Miocene through to the Rancholabrean of the Pleistocene, living from ~10.3 Mya—11,000 years ago, existing for approximately .-Taxonomy:The generic name...
, which means "giant claw" is a widespread North American genus, lived past the close of the last (Wisconsin) glaciation, when so many large mammals died out. Remains have been found as far north as Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
and the Yukon
Yukon
Yukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....
. Ongoing excavations at Tarkio Valley in southwest Iowa may reveal something of the familial life of Megalonyx. An adult was found in direct association with two juveniles of different ages, suggesting that adults cared for young of different generations.
The earliest known North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n megalonychid, Pliometanastes protistus, lived in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and the southern U.S. about 9 million years ago, and is believed to have been the predecessor of Megalonyx. Several species of Megalonyx
Megalonyx
Megalonyx is an extinct genus of giant ground sloths of the family Megalonychidae endemic to North America from the Hemphillian of the Late Miocene through to the Rancholabrean of the Pleistocene, living from ~10.3 Mya—11,000 years ago, existing for approximately .-Taxonomy:The generic name...
have been named; in fact it has been stated that "nearly every good specimen has been described as a different species". A broader perspective on the group, accounting for age, sex, individual and geographic differences, indicates that only three species are valid (M. leptostomus, M. wheatleyi, and M. jeffersonii) in the late Pliocene and Pleistocene of North America. Although work by McDonald lists five species.
Jefferson's ground sloth has a special place in modern paleontology
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
, for Thomas Jefferson
Thomas Jefferson
Thomas Jefferson was the principal author of the United States Declaration of Independence and the Statute of Virginia for Religious Freedom , the third President of the United States and founder of the University of Virginia...
's letter on Megalonyx, read before the American Philosophical Society
American Philosophical Society
The American Philosophical Society, founded in 1743, and located in Philadelphia, Pa., is an eminent scholarly organization of international reputation, that promotes useful knowledge in the sciences and humanities through excellence in scholarly research, professional meetings, publications,...
of Philadelphia, in August 1796, marked the beginning of vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
paleontology in North America. When Lewis and Clark set out, Jefferson instructed Meriwether Lewis to keep an eye out for ground sloths. He was hoping they would find some living in the Western range. Megalonyx jeffersonii was appropriately named after Thomas Jefferson.
Megatheriidae
Megatherium
Megatherium was a genus of elephant-sized ground sloths endemic to Central America and South America that lived from the Pliocene through Pleistocene existing approximately...
(given its name 'great beast' by Georges Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
) and Eremotherium
Eremotherium
Eremotherium is an extinct genus of actively mobile ground sloth of the family Megatheriidae, endemic to North America and South America during the Pleistocene epoch...
. The skeletal structure of these ground sloths indicates that the animals were massive. Their thick bones and even thicker joints (especially those on the hind legs) gave their appendages tremendous power that, combined with their size and fearsome claws, provided a formidable defense against predators.
The earliest megatheriid in North America was Eremotherium eomigrans which arrived 2.2 million years ago, after crossing the recently formed Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
nian land bridge. With more than five tons in weight, 6 meters in length, and able to reach as high as 17 feet (5.2 m), it was taller than an African Bush Elephant
African Bush Elephant
The African Bush Elephant or African Savanna Elephant is the larger of the two species of African elephant. Both it and the African Forest Elephant have usually been classified as a single species, known simply as the African Elephant...
bull. Unlike relatives, this species retained a plesiomorphic extra claw. While other species of Eremotherium had four fingers with only two or three claws, E. eomigrans had five fingers, four of them with claws up to nearly a foot long.
Nothrotheriidae
Recently recognized, members of Nothrotheriidae are often associated with those of the MegatheriidaeMegatheriidae
Megatheriidae is a family of extinct ground sloths that lived from approximately 23 mya—11,000 years ago, existing for approximately .Megatheriids appeared later in the Oligocene, some 30 million years ago, also in South America. The group includes the heavily-built Megatherium and Eremotherium...
, and together the two form the superfamily Megatheroidea. The most prominent members of the group are the South American genus Thalassocnus
Thalassocnus
Thalassocnus is an extinct genus of semi-aquatic or aquatic marine sloth from the Miocene and Pliocene of South America. Fossils found to date have been from the coast of Peru. They were apparently grazers of sea grass and seaweed. Over time, they apparently shifted from a preference for feeding...
, known for being aquatic, and Nothrotheriops
Nothrotheriops
Nothrotheriops is a genus of Pleistocene ground sloth found in North and South America. This genus of bear-sized xenarthran was related to the much larger, and far more famous Megatherium, although it has recently been placed in a different family, Nothrotheriidae.-Discovery and species:Fossils of...
from North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
.
The last ground sloths in North America belonging to Nothrotheriops died so recently that their petrified dung (coprolite
Coprolite
A coprolite is fossilized animal dung. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour rather than morphology. The name is derived from the Greek words κοπρος / kopros meaning 'dung' and λιθος / lithos meaning 'stone'. They...
s) has remained undisturbed in some caves, as if it were just recently deposited. One of the skeletons, found in a lava tube
Lava tube
Lava tubes are natural conduits through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption. They can be actively draining lava from a source, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like...
(cave) at Aden Crater
Aden Crater
Aden Crater is a crater in Doña Ana County, New Mexico. It is located between Santa Teresa, New Mexico and Las Cruces, New Mexico. The crater is a remote location that can be hiked and explored. The area has deep caverns that can be very dangerous to inexperienced hikers and spelunkers. A ground...
, adjacent to Kilbourne Hole
Kilbourne Hole
Kilbourne Hole is a maar volcanic crater, located west of the Franklin mountains of El Paso, Texas, in the Potrillo Volcanic Field of Doña Ana County, New Mexico. Nearby Hunt's Hole lies several miles just south of Kilbourne Hole. These holes are rare examples of volcanic action without a...
, New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, still had skin and hair preserved, and is now at the Yale Peabody Museum. The American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
in New York City has a sample of dung with a note attached to it that reads "deposited by Theodore Roosevelt
Theodore Roosevelt
Theodore "Teddy" Roosevelt was the 26th President of the United States . He is noted for his exuberant personality, range of interests and achievements, and his leadership of the Progressive Movement, as well as his "cowboy" persona and robust masculinity...
". The largest samples of Nothrotheriops dung can be found in the collections of the Smithsonian Museum.
Mylodontidae
Corral
Corral is a town, commune and sea port in Los Ríos Region, Chile. It is located south of Corral Bay. Corral is best known for the forts of Corral Bay, a system of defensive batteries and forts made to protect Valdivia during colonial times. Corral was the headquarters of the system...
s when they could procure a young ground sloth, to raise the animal to butchering size. However, radiocarbon dates
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
do not support simultaneous occupation of the site by humans and sloths. Subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
remains like coproliths, fur and skin have been discovered in some quantities.
Orophodontidae
The orophodontid ground sloths constitute a rather small but quite distinct group. They are classified as a distinct mylodontan superfamilyTaxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
Orophodontoidea, the sister taxon to the Mylodontoidea.
In cryptozoology
CryptozoologistsCryptozoology
Cryptozoology refers to the search for animals whose existence has not been proven...
often identify the mapinguari
Mapinguari
The mapinguari or mapinguary , also known as the Isnashi , is a legendary cryptid said to resemble a ground sloth-like creature with red fur living in the Amazon rainforests of Brazil and Bolivia...
, a mythical forest creature of the upper Amazon basin
Amazon Basin
The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...
, with a surviving tropical ground sloth or folk memory
Folk memory
Folk memories is a term sometimes used to describe stories, folklore or myths about past events that have passed orally from generation to generation. The events described by the memories may date back hundreds, thousands, or even tens of thousands of years and often have a local significance...
of these animals.
External links
- Sloth World: An Online Sloth Bibliography.
- Picture and information about a ground sloth skeleton on display at the University of Georgia's Science Library.
- Academy of Natural Sciences ground sloth page.
- Illinois State Museum ground sloth page.
- Ground sloths at La Brea.
- Eremotherium in Florida.
- Have some ground sloths survived in Argentina?
- Ground sloths in general.
- Western Center for Archaeology and Paleontology Hemet, CA