New! Sign up for our free email newsletter.
Science News
from research organizations

Ancient DNA reveals evolution of giant bears in the Americas

Date:
April 20, 2016
Source:
University of Adelaide
Summary:
Researchers are shedding new light on the evolution of what are believed to be the largest bears that ever walked the Earth.
Share:
FULL STORY

The work of University of Adelaide researchers is shedding new light on the evolution of what are believed to be the largest bears that ever walked the Earth.

Dr Kieren Mitchell, from the University's Australian Centre for Ancient DNA, School of Biological Sciences, has a new paper just published in Biology Letters.

He writes: "During the Pleistocene (2.5 million years ago -- 11 thousand years ago) giant bears weighing over 1,000kg roamed both North and South America. These giants belonged to a now practically extinct subfamily of bears -- Tremarctinae -- which is today only represented by the small, herbivorous Andean spectacled bear (Tremarctos ornatus).

"The giant North American bears (Arctodus) and South American bears (Arctotherium) have long been believed to be each others' closest relative. However, by comparing ancient DNA data obtained from representatives of the two extinct genera and comparing them with the living species, we were able to show that Arctotherium is most closely related to Tremarctos and not Arctodus.

"The implication of this result is that these bears represent a remarkable instance of convergent evolution, as giant bears appear to have evolved independently in both North and South America.

"This convergent evolution would have arisen in response to similar environmental conditions on both continents, most likely an abundance of large herbivore carcasses (killed by smaller predators), which Arctodus and Arctotherium could effectively dominate, and a lack of competing scavengers."


Story Source:

Materials provided by University of Adelaide. Note: Content may be edited for style and length.


Journal Reference:

  1. Kieren J. Mitchell, Sarah C. Bray, Pere Bover, Leopoldo Soibelzon, Blaine W. Schubert, Francisco Prevosti, Alfredo Prieto, Fabiana Martin, Jeremy J. Austin, Alan Cooper. Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America. Biology Letters, 2016; 12 (4): 20160062 DOI: 10.1098/rsbl.2016.0062

Cite This Page:

University of Adelaide. "Ancient DNA reveals evolution of giant bears in the Americas." ScienceDaily. ScienceDaily, 20 April 2016. <www.sciencedaily.com/releases/2016/04/160420102532.htm>.
University of Adelaide. (2016, April 20). Ancient DNA reveals evolution of giant bears in the Americas. ScienceDaily. Retrieved March 18, 2024 from www.sciencedaily.com/releases/2016/04/160420102532.htm
University of Adelaide. "Ancient DNA reveals evolution of giant bears in the Americas." ScienceDaily. www.sciencedaily.com/releases/2016/04/160420102532.htm (accessed March 18, 2024).

Explore More

from ScienceDaily

RELATED STORIES