Thursday, March 1, 2012

Giant Ground Sloth; the Other White Meat

I'm always a little skeptical when I read reports about conclusive evidence of early humans feeding on ice age animals.  I'm sure it happened, but I have a difficult time believing that scratches and scrapes on fossilized bones are evidence for human tool use to butcher ice age animals.  It just seems that there are so many potential sources for scrapes and scratches on fossilized bone from animal scavengers to aspects of the decay and fossilization process to environmental processes post fossilization.

Jefferson's Ground Sloth
Orton Geology Museum
Ohio State University
That being said, researchers from the Cleveland Museum of Natural History have published in the February issue of the journal World Archaeology that they have discovered evidence of human feeding on Jefferson's Ground Sloth based on cut marks found on bones of the species.

This is the first time evidence have been found of humans potentially feeding on a giant sloth.  Other previous studies have looked at remains of mammoths and mastodons for potential evidence of human tool use.

Researchers examined 10 animal bones that were discovered in 1998.  The bones were discovered in the collections of the Firelands Historical Society Museum in Norwalk, Ohio.  The bones were thought to have originally been discovered in a small wetland in Huron County, Ohio, though the exact location is not exactly known.

The left femur of the sloth shows evidence of 41 incision marks.  The bone was radiocarbon dated to somewhere between 13,435 to 13,738 years old.  The age of the bones and the incision marks suggest that this is the earliest evidence of prehistoric human activity in Ohio.

Jefferson's Ground Sloth model
Cincinnati Museum of Natural History

There have only been three specimens of Giant Ground Sloth found in Ohio and this specimen--known as the "Firelands Ground Sloth"--is considered to be one of the largest specimens of the species discovered anywhere.  In life, it weighed well over a ton.

The determination that the incisions on the bones were made with human-made, non-metallic tools, was made through microscopic analyses.

Modern paleontological techniques have revealed evidence of the colors of various prehistoric animals, the presence of bio-molecules preserved in bone, and many other advances.  I'd eventually like to see similar techniques, beyond just microscopic evaluation, used on ice age bone material to provide better support for the use of human-made tools on bones.