Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Wednesday, December 03, 2014

Nature and Prehistoric Extinction

"It's not human nature just to see everything in your path and want to kill it."
"To think of scattered populations of Ice Age people with primitive technology driving huge animals to extinction, to me is almost silly."
"You can't just hold up a flag and say it was one thing that led to the extinction of all these species. It wasn't like they all collapsed in one instant across the continent."
"They migrated northward; 'Let's come up to Alaska and the Yukon on a vacation to see what it's like', but then when conditions got cold again they were immediately wiped out."
Grant Zazula, chief paleontologist, Yukon Territory
Both Colombian mammoths and mastodons once roamed North America.  - Velizar Simeonovski, The Field Museum, Chicago

We can empathize, we certainly can, as fellow mammals exposed to the dread certainties of the dead of a Canadian winter in this northern hemisphere. And being of the supposed higher order of mammalian existence, we have been gifted extraordinarily by nature in the ability to manipulate our environment, which has led over thousands of years to the kind of technology that enables us to shelter from extreme cold and the exigencies of misery brought down by winter conditions.

Those great, ponderous beasts known as mastodons that once lived on the Earth, died out 65,000 years earlier than did their near relations who existed in warmer atmospheres to the south of the Canadian Yukon and American Alaska. Mastodons, living in the far, frozen North that early man in fact had no knowledge of, since they died out long before early humans came on the scene.

Photo: American Mastodon, Mammut americanum.

Logo of - Canadian Museum of Nature.American mastodons were among the largest living land animals during the ice age. They ranged from Alaska and Yukon to central Mexico, and from the Pacific to Atlantic coasts.
Compared to living elephants and mammoths, American mastodons were squatter—from 2 to 3 m (7 to 10 ft.) in shoulder height—and longer—about 4.5 m (15 ft.).
Their upper tusks extended 2 m (7 ft.) or more beyond the sockets, and some mastodons had vestigial tusks in their lower jaws. The tusks were probably used for breaking off branches of conifer trees to eat.
Their cheek teeth consisted of paired, blunt cones covered with thick enamel—useful for browsing on trees and shrubs. Coarse, reddish hair has been found on the best-preserved specimens.
Their preferred habitat was open spruce woodlands, spruce forests and marsh. Their diet included conifer twigs and cones, leaves, coarse grasses, mosses and swamp plants.
In Canada, most mastodon remains (more than 60 specimens by 2008) have been found in deposits that postdate the last glaciation in southern Ontario. Fossils have been found in every province and territory except Nunavut, Newfoundland and Labrador, and Prince Edward Island.

A new Canadian-led study claims that the fate of the prehistoric beasts was dictated by nature herself, which is to say her elements of extreme cold, wind and icy conditions for which mastodons were unprepared to adapt themselves. They hadn't been imbued by nature to survive those elements, although human beings were, with their larger brains, their ability to learn how to reason and extrapolate from experience, and to manipulate with their opposable thumbs.

But this is not a story about humankind. It is a study whose claim is that those great beasts gave up the collective ghost in a flurry of chill-ill-will. Published in the Proceedings of the National Academy of Sciences, 36 mastodon bones derived from across Canada and the United States were carbon dated to extract the data that led to that conclusion. Research discovered that the beasts perished before we came long.

Therefore, early man could not conceivably have led, through hunting, which is to say over-hunting, to their catastrophic extinction. That credit goes entirely to an excess of nature. Paleontological wisdom has clung to the theory that many North American Ice Age mammals ranging from mammoths to giant sloths to mastodons met their fate at the end of "Paleo-Indians" spears.

The new research holds, contrary-wise, that mastodons, experiencing shifting environmental conditions were unable to survive in the new colder climate. Their appearance on what now is the Canadian North seems to have been brief, occurring during an interglacial period of temperature and conditions similar to the present day's. As colder temperatures intruded, mastodon herds in the south joined their cousins' extinction, about 10,500 years ago.

According to Ross Phee, a researcher at the American Museum of National History, co-author of the Yukon study, a small population of mastodons might have survived around the Great Lakes where humans indeed may have dealt the final blow to their existence. "That's a very different scenario from saying the human depredations caused universal loss of mastodons across their entire range within the space of few hundred years, which is the conventional view."

Mammoths, unlike mastodons, were able to survive in the frozen North, living there until some ten thousand years ago. Mammoth bones are regularly dug up around Yukon gold mines. Much of the area had been unaffected by the last Ice Age glaciers, leaving the soil frozen with the intact bones, skin and footprints of prehistoric creatures long-extinct. Mastodon bones, however, represent rare finds in the otherwise fossil-rich Yukon.
george church cgi
livescience: While the entire team hopes to find enough DNA to clone a mammoth from scratch, that could be tricky. For one, DNA is delicate and must be stored at cold, constant humidity in order to be preserved. Harvard University researcher George Church hopes to overcome those challenges one way or another. (Photo credit: Renegade Pictures)

Labels: ,


Post a Comment

<< Home

()() Follow @rheytah Tweet