Washington: Global warming may be threatening the survival of polar bears, but similar climactic changes in the past have played an important role in the evolution of the species, a new study has claimed.
Researchers at the State University of New York at Buffalo, who have sequenced the mitochondrial genome of an ancient polar bear's jawbone, said that similar climactic sifts have played an important part in bringing the species into existence.
The 110,000 to 130,000 years old jawbone revealed that the species likely split from brown bears just 150,000 years ago, at a time when specialising in arctic living quickly became an advantage rather than a liability, they said.
Judging from comparisons of modern bear genetics, it is estimated that the common ancestors of truly modern polar bears lived about 45,000 years ago, surviving what may have been a population bottleneck resulting from changing climate patterns, journal Proceedings of the National Academy of Sciences said.
"From isotope analysis, we were able to get a good idea of its feeding ecology, and it fits very well at the top of the feeding chain of marine mammals like polar bears today," lead author Charlotte Lindqvist said.
And even without the genetic revelations, the jawbone itself gives a few hints about the individual. "We can say it was probably a male adult polar bear of a size which can be found in modern polar bears and had a feeding ecology similar to today," Lindqvist says.
PTI
First Published: Thursday, March 04, 2010, 09:29