Friday, December 08, 2006

Mammoth rubbings
If this can be proved, it's very cool.
On a sunny, brisk late November day, Edward Breck Parkman hunched over and rubbed his back, pachyderm-like, against a large rock jutting out of a meadow on the rugged, green coastline near Bodega Bay.

The senior archaeologist for the California Department of Parks and Recreation does not usually play-act in the field, but on this day he wanted to re-create in real life the scene from the late Pleistocene Epoch that he has brought to life in the minds of scientists and researchers around the globe.

"I'm a mammoth, a big old mammoth, the leader of the tribe," he declared, eyes wide and a look of wonder sneaking out around his bushy, graying goatee. "I like these overhanging rocks because they give a better angle to rub up against."

Parkman believes, and he has a growing body of evidence to prove that mammoths and other large Ice Age creatures once used these very rocks near Duncan's Landing, along the Sonoma Coast State Beach, to scratch their backs. He claims the giant mammals rubbed so much that large swaths of rock have been buffered smooth.


On this particular outcropping there are uncharacteristic patches of dark, smooth polished rock that can be seen up to a height of 14 feet.

"This goes up 14 feet, and then it stops," Parkman said, pointing to an area as smooth as honed marble. "That's the size of an adult male mammoth. And there are a dozen other polished rocks within sight of us."

Experts on rock polish have examined the smooth areas, including a geologist from Sonoma State University who reported that he couldn't find any other geological explanation for the rubbings. In fact, a microscopic analysis of the polished rock shows that the smooth areas are virtually identical to known elephant rubbing rocks in Africa, down to the tiny scratches caused by gravel particles on the skin.

As rare as fossils are, direct evidence of the behavior of extinct animals is even more rare and usually determined by making analogies to living species in a similar ecological niche. Rubbing is quite common among large mammals who don't have the flexibility to scratch everywhere. In the northwestern woods, I've seen trees with tufts of fur in the bark where bears have leaned in to scratch their backs. Elephants rub as part of their grooming to remove dust, derma, bugs, and just to scratch.

The mammoths in this area would have been Columbian Mammoths, the slightly larger and older cousins of the Woolly Mammoth. While Woolly Mammoths lived on the steppe-like, cold, northern prairies, Columbian Mammoths lived in forest and plain all through North America. Their bones have been found from the Canadian border to central Mexico.

Short of finding sone hairs in a crack in the rocks, Parkman is going to have a rough time proving his theory. Just becase something makes sense doesn't mean it's correct. Still, it's an exciting concept.

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