Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ancient fossil offers new clues to brown bears past

15.11.2004


This 26,000 year old brown bear fossil recently found near Edmonton, Alberta, is rewriting the history of brown bears in North America. The discovery by a UAF researcher and his colleagues are reported in Nov. 12 issue of "Science". Photo by Paul Matheus


While nosing around the Quaternary mammal collection at the Provincial Museum of Alberta two years ago, Paul Matheus, a paleontologist with the Alaska Quaternary Center, came across a brown bear fossil that seemed out of place. The fossil had been collected by Jim Burns, curator of Quaternary mammals at the PMA a few years earlier near Edmonton, Alberta, in gravels that date to before the last ice age (older than 24,000 years). If this was true, Matheus thought, it could be a very important find. Burns loaned the specimen to Matheus so he could take it back to the University of Alaska Fairbanks to confirm its age using radiocarbon dating methods. Results showed the bear was indeed about 26,000 years old, and the two researchers realized the fossil’s signficance-the history of brown bears in North America would have to be rewritten.

The ancestors of modern brown bears in North America are believed to have migrated from Asia to Alaska and Yukon (then a part of Beringia) between 50,000 and 100,000 years ago, and old brown bear fossils are not particularly uncommon in Beringia. Between roughly 13,000-23,000 years ago, the route from Beringia to areas of the continent further south was blocked by continental glaciers, so brown bears were more or less bottled up in Beringia. The oldest brown bear fossils south of Beringia, in areas like southern Canada and the northern U.S., are about 12,000-13,000 years old, so paleontologists concluded that’s when they first arrived.

"It’s always been a mystery, though, why brown bears didn’t migrate farther south if they were in Beringia as early as 100,000 years ago and the passage south wasn’t blocked by glaciers until about 23,000 years ago," said Matheus. "The discovery of the Edmonton specimen indicates that brown bears migrated south much earlier than previously thought."



The recent findings and their implications, are the subject of an article in the Nov. 12 issue of the journal Science titled Pleistocene Brown Bears in the Mid-Continent of North America.

In order to really nail the significance of the find, Matheus and Burns needed one more piece of important information-they needed to know something about the fossil brown bear’s genetic identity. So, they brought in colleagues from the University of Oxford and the Max Planck Institute in Germany to sequence mitochondrial DNA from the specimen and assign the bear to one of the known genetic populations of modern and ancient brown bears. This was possible because of a previous collaborative study by Matheus and the Oxford lab using ancient DNA to uncover the population structure of ancient brown bears in Beringia. "One thing that earlier study could not explain was the ancestry of modern brown bears in the southern part of their range, in places like southern Alberta, British Columbia, Montana, and Idaho," said Matheus. "Those bears belong to a genetic population thought to be extinct in North America for as much as 35,000 years."

Consequently, paleontologists and geneticists have found it difficult to explain where the ancestors of southern brown bears came from when ice sheets retreated about 13,000 years ago-their genetic type did not exist in Beringia at that time. DNA results in the current study show that the new Edmonton specimen belongs to the same genetic group as modern southern brown bears.

The age and genetic identity of this bear mean that brown bears not only made it far south sooner than previously thought, but that those bears in the Edmonton area about 26,000 years ago were very close relatives of southern bears we see today. "Its like finding a missing piece of a puzzle, or even a proverbial missing link," said Matheus. "Their ancestors must have been stuck south of the ice sheets at the peak of the last ice age, 13,000-23,000 years ago because Edmonton was covered with ice most of that time. That represents a real shift in ideas about brown bear evolution in North America."

Matheus is a research scientist at the Alaska Quaternary Center and a research associate at the Institute of Arctic Biology. Both are located on the University of Alaska Fairbanks campus.

CONTACT: Paul Matheus, at (867) 456-7551, or e-mail ffpem@uaf.edu or contact Carla Browning at (907) 474-7778 or carla.browning@uaf.edu for additional contact information.

Paul Matheus | EurekAlert!
Further information:
http://www.uaf.edu

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>