Monday, January 27, 2014

The Extinction of the Giant Sloth

Giant sloth fossils at the Natural History Museum at the University
of Florida in Gainesville.  Worth a visit!  Click for photo credit.
During last week's South America week, I wrote a post about sloths in the suburbs of Caracas.  I thought I would follow up with a brief post about the extinct giant sloth.

Many do not realize it, but giant sloths lived across North and South America and went extinct just a short while ago.  They weighed up to 4 tons and were approximately the same size as an elephant.  They were about 20 feet long.  As large vegetarians, they had few natural enemies.

They started to go extinct across the Americas when people first came into the continents across the Bering Land Bridge in the most recent Ice Age.  They were largely extinct on the continents about 10,000 years ago, although the last one in the Caribbean disappeared about 2,000 years ago (the Caribbean was the last area settled by humans in the Americas).  Some have claimed that they have seen them in the mountains of the Andes, although that is probably just a Bigfoot type of rumor.  The giant sloths didn't have a chance against the early settlers.  They were easy food and never developed defensive skills since they didn't really have any major predators.

Many fossils of this creature have been found in the Cenozoic rocks of Florida.  They were probably very common creatures throughout the continents, but due to the good preservation of fossils in Florida from the Cenozoic, we have learned much about them.


Bret Bennington said...

Thomas Jefferson was the first American to describe a fossil of a North American giant sloth. While vice president Jefferson received by mail a large claw from a Colonel John Stuart of West Virginia. Jefferson traveled to Philadelphia in 1797 to present a paper on his identification of the claw as belonging to an animal of "the lion kind, but of most exaggerated size." However, shortly before the meeting of the American Philosophical Society he was to attend, Jefferson saw a description of a similar European fossil identified as a relative of the sloth. Jefferson revised his identification and the fossil and species were subsequently named Megalonyx jeffersonii (Jefferson's giant claw) in his honor.

Bob Brinkmann said...

How cool! Thanks for posting this. I had no idea. I knew Jefferson was a renaissance kind of guy, but I never knew he dabbled in paleontology! Wowza!