Posted on 12/10/2007 11:13:56 AM PST by blam
Ancient polar bear jawbone found
By Jonathan Amos
Science reporter, BBC News, San Francisco
The jawbone is about 23cm long
What may be the oldest known remains of a polar bear have been uncovered on the Svalbard archipelago in the Arctic.
The jawbone was pulled from sediments that suggest the specimen is perhaps 110,000 or 130,000 years old.
Professor Olafur Ingolfsson from the University of Iceland says tests show it was an adult, possibly a female.
The find is a surprise because polar bears are a relatively new species, with one study claiming they evolved less than 100,000 years ago.
If the Svalbard jawbone's status is confirmed, and further discoveries can show the iconic Arctic beasts have a deeper evolutionary heritage, then the outlook for the animals may be more positive than some believe.
Age 'confidence'
"We have this specimen that confirms the polar bear was a morphologically distinct species at least 100,000 years ago, and this basically means that the polar bear has already survived one interglacial period," explained Professor Ingolfsson.
POLAR BEAR (URSUS MARITIMUS)
* Largest of five living bear species of Ursus genus
* Brown bear (U. arctos) is nearest evolutionary cousin
* Two species able to produce fertile hybrid offspring
* Highly specialised predator of seals - but will take other prey
* Global population of polar bears may number 20-25,000
* Most recent IUCN Red List status: Vulnerable
* Previous oldest recovered remains are about 70,000 years old
"And what's interesting about that is that the Eeemian - the last interglacial - was much warmer than the Holocene (the present).
"This is telling us that despite the ongoing warming in the Arctic today, maybe we don't have to be quite so worried about the polar bear. That would be very encouraging."
The jawbone's discovery is being presented here in San Francisco at the American Geophysical Union (AGU) Fall Meeting.
The specimen was found at Poolepynten on Prins Karls Forland, a narrow strip of land on the far west of the archipelago.
The sediments there are well-described, and record at least two glaciations sandwiched with marine sequences. In other words, they record periods when Poolepynten was alternately covered by ice and water.
These periods are understood in good detail by Professor Ingolfsson's team, so although direct dating at the dig site gives an age range for the bone of 80-140,000 years ago, the group is confident the specimen can be placed at the upper end of this scale.
London detour
The 23cm-long bone itself retains some critical details that have helped identify it.
"It is very well-preserved," Professor Ingolfsson told BBC News.
"We can measure various parameters, such as the cheek-teeth row-length, and the size of the hole made by the third molar - which is very characteristic of polar bears. We've compared all this, both to fossil and recent materials, and there's no question it's a polar bear." They speculate it was a female bear.
Researchers have studied the DNA of modern polar bears to try to gauge when the Arctic animals separated from brown bears, their nearest evolutionary cousins.
Different models have variously put the radiation as near as 70,000 years ago and as distant as 1-1.5 million years ago. One of the problems has been in finding the ancient specimens to put alongside, and constrain, these genetic estimates.
Until recently, one of the oldest polar bear specimens was thought to be British - a 70,000-year-old animal found at Kew Bridge in London.
The presumption was that the creature lived at a lower latitude during a period when ice sheets were more extensive.
But scientists are now confident the Kew animal was in fact a brown bear.
"It's a huge bear; it's a runner - a hunting bear," said Andy Currant, a palaeontologist from London's Natural History Museum. "It's got some of the features of a polar bear, but it's undoubtedly a brown bear.
"With something like polar bears, to make an identification you've got to have a skull or a lower jaw - they've got very reduced teeth, rather surprisingly, and you've got to see that. So I was interested to learn that [Ingolfsson's group] has that."
Hidden Arctic
Building up a more detailed picture of the ancient history of polar bears will be challenging, though. The animals spend much of their lives out on the ice, and when they die their remains are likely to be scavenged by other creatures or fall to the bottom of the Arctic Ocean. Finds will continue to be extremely rare.
The sediments record the passing of ice and water Concern over the bears' future status centres on the observations of shrinking ice in what is a rapidly warming Arctic. The ice provides a platform from which to hunt ringed, and other, seals. If the ice is diminished and the bears cannot adapt quickly, many of them may be squeezed out of their ecological niche.
Professor Ingolfsson is hopeful the bears will cope - and believes the palaeo-record will offer some reassurance.
"The polar bear is basically a brown bear that decided some time ago that it would be easier to feed on seals on the ice. So long as there are seals, there are going to be polar bears. I think the threat to the polar bears is much more to do with pollution, the build up of heavy metals in the Arctic.
"This is just how I interpret it. But this is science - when you have little data, you have lots of freedom."
The team, which includes Professor Oystein Wiig from the University of Oslo, Norway, will develop its research on the Svalbard specimen by trying to extract DNA.
GGG Ping?
Al Gore have anything to do with this?
Killed by global warming, no doubt.
look at that polar bears died before global warming. Go get Al Gore.
Samson killed 20 thousand with the jawbone of an ass.
Algore will kill 20 thousand asses with the jawbone of a polar bear........
An article out of the BBC San Fran branch on polar bears and not one single mention of climate change or global warming?
Some reporter is gonna be out of a job tomorrow.
So Polar Bears’ nearest cousin is the Brown Bear (Grizzly Bear). Not a big surprise. Didn’t realize that Homo Sapiens has been around longer than Polar Bears.
Maybe this will help the box office receipts of “The Golden Compass”.
Of course, one should never question the evolutionists; their theories should be accepted at face value.
“the specimen is perhaps 110,000 or 130,000 years old.”
“one study claiming they evolved less than 100,000 years ago.”
Ignore any inconsistencies. Of course they existed 30,000 years before they evolved. You have to accept that on faith.
yes we’re not exactly talking about double blind controlled studies here.
You are right. Much better to shut off one’s brain and just say they came into existence 6K years ago,
Algore is an ass. He’ll have to smite himself!
Darwinism and creationism both have a large faith component. The difference is that the Creationists acknowledge that.
I’ll have to remember to drop in at DC in a few days to see if this thread shows up over there.
Occasional Brown Bears are found with a sub-coat of the specialized white fur of the Polar Bear.
The prototypes were 110,000-130,000 years ago. Then, just like the auto companies, a bit of trim changes every 10,000 years, and then bring out a 'new' model every 30,000 years.
A sharper hood ornament; thicker upholstery; heated seat cushion; slap on wider, studded whitewalls, and add $1,500 to the base price.
After about 100,000-150,000 years retire the model, and bring out a "new" marque, and add still another $3,000 to the base price, and start over.
People are going to be upset when they find out the bear fight in Golden Compass wasn’t CGI.
Polar bears have black skin and their hair works similar to a fiber optic and channels light down to the black skin. They're also difficult to detect on infra-red sensing equipment because they conserve their heat so well.
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Gods |
Thanks Blam.The jawbone was pulled from sediments that suggest the specimen is perhaps 110,000 or 130,000 years old... The find is a surprise because polar bears are a relatively new species, with one study claiming they evolved less than 100,000 years ago. If the Svalbard jawbone's status is confirmed, and further discoveries can show the iconic Arctic beasts have a deeper evolutionary heritage, then the outlook for the animals may be more positive than some believe. "We have this specimen that confirms the polar bear was a morphologically distinct species at least 100,000 years ago, and this basically means that the polar bear has already survived one interglacial period," explained Professor Ingolfsson.To all -- please ping me to other topics which are appropriate for the GGG list. |
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