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On the menu: giant sloth

March 7, 2012 — 

giant sloth fossil

A University of Manitoba archeologist and colleagues have confirmed it: about 13,500 years ago some North Americans cut into the – probably vapid – meat of the giant Jefferson Ground Sloth for the first time.

Prior to this feast in what is now Ohio, this 1.5 ton vegetarian giant that went extinct 10,000 years ago, was off the menu. There was no evidence of humans having hunted or butchered them. Then, microscopic scratches on the bones were noticed and their analysis got researchers excited for three reasons: first, they were evidence for stone tool marks on the bones; second, this was the first evidence for hunting or scavenging of Ice Age sloths in North America; and third, this provides the oldest evidence of prehistoric human activity in Ohio, which, 13,000 years ago, was when much of North America was still under a thick.

marks on giant sloth boneUniversity of Manitoba Archaeologist Haskel Greenfield was invited by the papers lead author, Brian Redmond, curator of archeology at the Cleveland Museum of Natural History, to examine the 41 incisions marring the femur bone dated to be from 13,435 to 13,738 years ago. This is 700 years earlier than the oldest well-dated ancient human inhabitants of North America, the Clovis people. One of Greenfield’s specialties is examining microscopic marks on bones to determine if they were made by teeth, trampling, stone or metal tools, or perhaps even an errant shovel at the dig site.

“No other ancient giant ground sloths have shown any evidence of human’s hunting or butchering them, unlike other contemporary megafauna, such as mastodons, bison, or giant beavers,” Greenfield said. “But when I saw that these marks on the bones were made from stone tools, what went through my mind when I discovered this was, ‘Who wants to eat a ground sloth?’”

Greenfield notes that we do not know the exact context of this supper. People could have been starving and came across an already dead animal; it’s impossible to know since researchers only have the part of the skeleton to work from, which was originally dug up in 1915 and then sat forgotten in a drawer until 1998. Greenfield got his first glimpse of the bone in 2008 on a visit to the Cleveland Natural History Museum, when he was invited to participate in the analysis.

“These humans could have hunted it. I don’t know. The only thing that is clear is that there are disarticulation marks: they were separating the limbs from each other; they were cutting the joints. And some marks show that they were filleting the meat off the bone.”

The “Firelands Ground Sloth”, as the specimen is named, is one of only three specimens of Megalonyx jeffersonii known from Ohio. Based on measurements of the femur, tibia and other bones, it is one of the largest individuals of this species on record. It had an estimated body mass of 1,295 kilograms (2,855 pounds). The species went extinct at the end of the last glacial period, about 10,000 years ago.

The Manitoba Museum has a giant sloth on display for those curious to see what sort of animal these Ice Age North Americans supped on for the first — and perhaps last — time.

Other co-authors are Dr. Brian Redmond (Cleveland Museum of Natural History), Dr. H. Gregory McDonald (US National Park Service), and Matthew L. Burr (Firelands Historical Society). A link to the published article is: http://dx.doi.org/10.1080/00438243.2012.647576

Research at the University of Manitoba is partially supported by funding from the Government of Canada Research Support Fund.

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