Featured Research

from universities, journals, and other organizations

True causes for extinction of cave bear revealed: More human expansion than climate change

Date:
August 25, 2010
Source:
Plataforma SINC
Summary:
The cave bear started to become extinct in Europe 24,000 years ago, but until now the cause was unknown. An international team of scientists has analyzed mitochondrial DNA sequences from 17 new fossil samples, and compared these with the modern brown bear. The results show that the decline of the cave bear started 50,000 years ago, and was caused more by human expansion than by climate change.

Ursus spelaeus male skull found in Cova Eiros (Triacastela, Lugo).
Credit: Grandal-D'Anglade et al.

The cave bear started to become extinct in Europe 24,000 years ago, but until now the cause was unknown. An international team of scientists has analysed mitochondrial DNA sequences from 17 new fossil samples, and compared these with the modern brown bear. The results show that the decline of the cave bear started 50,000 years ago, and was caused more by human expansion than by climate change.

"The decline in the genetic diversity of the cave bear (Ursus spelaeus) began around 50,000 years ago, much earlier than previously suggested, at a time when no major climate change was taking place, but which does coincide with the start of human expansion," says Aurora Grandal-D'Anglade, co-author of the study and a researcher at the University Institute of Geology of the University of Coruρa.

According to the research study, published in the journal Molecular Biology and Evolution, radiocarbon dating of the fossil remains shows that the cave bear ceased to be abundant in Central Europe around 35,000 years ago.

"This can be attributed to increasing human expansion and the resulting competition between humans and bears for land and shelter," explains the scientist, who links this with the scarce fossil representation of the bear's prey in the abundant fossil record of this species.

In order to reach their conclusions, the team of scientists, led by the Max Planck Institute for Evolutionary Anthropology (Germany), studied mitochondrial DNA sequences from bear fossils in European deposits (Siberia, Ukraine, Central Europe and the Iberian Peninsula, specifically Galicia), and carried out a Bayesian analysis (of statistical probability).

The scientists also made comparisons with the modern brown bear (Ursus arctos) and with fossil samples of this species of bear, and managed to show why one became extinct and the other did not. In order to demonstrate this, the study analysed 59 cave bear DNA sequences and 40 from the brown bear, from between 60,000 and 24,000 years ago for the cave bear and from 80,000 years ago up to the present day for the brown bear.

Decline of the caves, extinction of the bears

The impoverishment of ecosystems during the last glacial maximum was "the 'coup de grace' for this species, which was already in rapid decline," the author explains.

The present day brown bear did not suffer the same fate and has survived until today for one simple reason -- brown bears did not depend so heavily on the cave habitat, which was becoming degraded, and this is why they did not follow the same pattern as the cave bears.

"Brown bears rely on less specific shelters for hibernation. In fact, their fossil remains are not very numerous in cave deposits," the Galician researcher says.

The definitive extinction of the cave bear "broadly" coincides with the last cooling of the climate during the Pleistocene (between 25,000 and 18,000 years ago), which may have led to a reduction in shelter and the vegetation that the animals fed on.

The cave bear inhabited Europe during the Late Pleistocene and became definitively extinct around 24,000 years ago, although it held out for a few thousand years longer in some areas, such as the north west of the Iberian Peninsula, than in other places. This ursid was a large animal, weighing 500 kg on average, and was largely a herbivore. The bear hibernated in the depths of limestone caves, where the remains of individuals that died during hibernation slowly accumulated over time.


Story Source:

The above story is based on materials provided by Plataforma SINC. Note: Materials may be edited for content and length.


Journal Reference:

  1. M. Stiller, G. Baryshnikov, H. Bocherens, A. Grandal d'Anglade, B. Hilpert, S. C. Munzel, R. Pinhasi, G. Rabeder, W. Rosendahl, E. Trinkaus, M. Hofreiter, M. Knapp. Withering Away--25,000 Years of Genetic Decline Preceded Cave Bear Extinction. Molecular Biology and Evolution, 2010; 27 (5): 975 DOI: 10.1093/molbev/msq083

Cite This Page:

Plataforma SINC. "True causes for extinction of cave bear revealed: More human expansion than climate change." ScienceDaily. ScienceDaily, 25 August 2010. <www.sciencedaily.com/releases/2010/08/100824082230.htm>.
Plataforma SINC. (2010, August 25). True causes for extinction of cave bear revealed: More human expansion than climate change. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2010/08/100824082230.htm
Plataforma SINC. "True causes for extinction of cave bear revealed: More human expansion than climate change." ScienceDaily. www.sciencedaily.com/releases/2010/08/100824082230.htm (accessed July 28, 2014).

Share This




More Earth & Climate News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) — A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) — A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com
Phoenix Thunderstorm Creates Giant Wall of Dust

Phoenix Thunderstorm Creates Giant Wall of Dust

Reuters - US Online Video (July 26, 2014) — A giant wall of dust slowly moves north over the Phoenix area after a summer monsoon thunderstorm. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Rare Lemur Among Baby Animals Debuted at Cleveland Zoo

Rare Lemur Among Baby Animals Debuted at Cleveland Zoo

Reuters - US Online Video (July 26, 2014) — A rare baby Lemur is among several baby animals getting their public debut at a Cleveland zoo. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins