Fossil Friday: Fan Edition! Megatherium, the great chomper!

Recently sloths have taken over social media in their own slow moving, adorable smiles, and fluffy way!

While these sloths are adorable, you wanted to find out more about their distant ancestors, the Megatherium, or Giant Ground Sloth on the Facebook poll that was running this week. Or should we say slowly hanging?

Most people are aware that sloths can be found in South America, or zoos, but Giant Sloth fossils have been found in both the United States and in parts of Western Canada as well! Ancient ground sloths though migrated from South America to North America where they lived happily during the Pliocene to the Pleistocene.

Now here are 3 GIANT interesting things about Giant Sloths that you probably did not know…until now!

Did you know…

Giant sloths used their tails to prop themselves up?

When looking at the skeleton of a giant sloth it is quite obvious that they had immense power and huge muscles! These muscles were used for something surprising through: to elevate the sloth!

Ground sloths used their tails and hind legs like a prop in order to reach the branches with the juiciest leaves higher up on trees! Then they used their large claws to bring their finds closer so that they could eat them.

What makes this even more interesting is that giant sloths could weigh up to 4.4 tons or the weight of an adult bull elephant. Now that’s a lot of power!

Giant sloths had algae in their fur just like the sloths of today?

In New Mexico, 100ft below the surface of an extinct crater, the remains of a Northrotheriops shastensis or a Shasta sloth, had been found. This Shasta sloth had evidence of an algae infestation in its coarse yellowish fur causing it to have a greenish tinge.

Why does algae appear in both extinct and alive sloths’ fur?

The answer is a symbiotic relationship.

For the modern sloth the algae gives them not only extra nutrients but it also gives them camouflage. Sloth fur has grooves creating the perfect habitat for algae. This is then passed from the mother sloth to her offspring.

This same symbiotic relationship is also the reason for the algae growing on the fur of ancient sloths; it had evolved with the sloth to be mutually beneficial.

People ate ground sloths?

Normally we do not think of sloths, much less giant ones, as a possibility on the dinner menu…but evidence shows that they had been!

Dr. Haskel Greenfield, a professor with the Anthropology Department at the University of Manitoba, traveled to Cleveland, Ohio at the request of Brian Redmond to check out some mysterious scratches that Redmond had discovered on the femur of a giant sloth, Megalonyx jeffersonii, in the collections room at the Cleveland Museum of Natural History.

Dr. Greenfield had no real expectations of the scratches; after all they could have just been gnawing marks from other creatures who were trying to get a piece of the carcass.

Amazingly, the marks in the femur where not made by animals at all!

The marks on the 700 year old bones had been created by stone tools on an animal that had recently died. The cuts found at the joints of the femur which indicate the possibility of the bones being separated from the meat as well as easier access to the sloth’s  tendons which could be used to make rope. All the marks created by human stone tools were on fresh bone leading to the conclusion of a recent death.

These marks further gave evidence of butchering as the pattern of the cuts associated with those of meat stripping rather than dis-articulation and being non-random or done with purpose.

Works Cited

Photo by Sebastian Molinares on Unsplash

Chung, E. (2012, March 08). Mega-Sloth likely on human’s ice age menu. Retrieved from CBC News:

Horne, G. (2010, April 14). Sloth fur has symbiotic relationship with green algae. Retrieved from BMC:

Kurten, B. (1988). Before the Indians. New York: Columbia University Press.

(2009). Megatherium. In G. Sharma (Ed.), Prehistoric Life: the definitive visual history of life on earth (p. 434). New York, New York, United States: DK Publishing.

Redmond, B. G., McDonald, H. G., Greenfield, H. J., & Burr, M. L. (2012, March). New Evidence for Late Pleistocene human exploitation of Jefferson’s Ground Sloth (Megalonyx jeffersonii) from northern Ohio, USA. World Archaeology, 44(1), 75-101. doi:10.1080/00438243.2012.647576

Suutari, M., Majaneva, M., Fewer, D. P., Voirin, B., Aiello, A., Friedl, T., . . . Blomster, J. (2010, March 30). Molecular Evidence for a Diverse Green Algal Community Growing in the Hair of Sloths and a Specific Association With Trichophilus Welckeri (Chlorophyta, Ulvophyceae). BMC Evolutionary Biology, 1-12. doi:10.1186/1471-2148-10-86

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