The Pleistocene Americas were home to many strange and massive creatures. The Giant Ground Sloth, with its upright body plan and massive, foot-long claws, stands out as an especially incredible looking creature.

This prehistoric mammal could grow over 20 feet tall and roamed the forests looking for food. They were far more massive than any living relatives today and certain Paleolithic sites have suggested human hunting could have had a hand in their extinction.

This specimen is a 5.45 inch fossilized sternum from Eremotherium, one of the massive ground sloths of the Late Pleistocene. It was recovered on private land in Florida and is estimated to be roughly 11,000 years old.

This is an especially exciting piece as you can see 11 points of contact where the animal's ribs connected. This was the connector piece which held the Eremotherium's skeleton together. This specimen comes with a handsome wood display stand and a certificate of authenticity.

Known for their great claws and ungainly appearance, ground sloths were a very successful family of mammals. Originating in South America, smaller species of ground sloth made their first appearance in the fossil record during the Oligocene Epoch 35 million years ago. Over millions of years in relative isolation, sloths grew in size becoming true giants only eclipsed by the mammoths.

Giant ground sloths certainly earned their name. Some of these creatures could grow taller than modern elephants, with foot-long claws to match. These powerful claws helped the ground sloths grab foliage from higher up on trees to eat.

The largest known species of sloth evolved during the Pliocene epoch in the midst of a period of great migration between North and South America. This "Great American Interchange" lasted millions of years, beginning with island hopping and peaking as animals crossed freely over the newly formed isthmus of Panama. This wide distribution means fossils have been found all across both continents and throughout the Caribbean, representing 80 genera that make up six families.

Curiously, Thomas Jefferson has a unique tie to these ground sloths. In 1796, just before Jefferson took office as the Vice President, he received bone fragments from Colonel John Stuart, who wanted his scientific opinion on the fossils. Although Jefferson first identified Megalonyx as a relative of the lion, he eventually discovered its similarities to fossil sloth engravings and changed his opinion. Like other religious men, the idea of extinction was controversial to Jefferson, who believed that his ground sloth still existed somewhere in the North American continent. Much like his lion assertion, this too proved to be false.

In 1788, the first fossil remains of the Megatherium genus were discovered in Argentina and shipped to the Royal Cabinet of Natural History in Madrid, Spain. Drawings of the assembled skeleton later reached the great French anatomist, Georges Cuvier, who identified the animal as a type of sloth in 1796. Cuvier originally thought the claws were used for climbing trees, but due to the animal's great size he changed his hypothesis settling on a surface or subterranean existence.

Modern studies of giant sloth skeletons and trackways found in Argentina and Nevada place the average top speed of the largest ground sloths at 1.68 meters per second or 3.7 miles per hour.  This is an average walking speed for most humans so it would seem the sloths were easy prey.  However, most ground sloths also possessed osteoderms, bony growths that would have provided some protection against predators. Even humans armed with the best technology of the time would have difficulty penetrating this thick armor at a distance, which meant getting in reach of this powerful animal's enormous claws.

The specimen is a part of a Eremotherium sternum, recovered on private land in Florida and dated to 11,000 years ago. Eremotherium stood roughly 20 feet tall and weighed over 3 tons. Their fearsome claws could grow over a foot long. These weren't just used for fending off attackers — their primary function was to pull down bark and other vegetation for the herbivorous mammal. For all their defensive attributes and intimidating size, these were peaceful creatures, who in spite of their osteoderm protection did not last long once human settlement of the Americas began.