Featured Research

from universities, journals, and other organizations

Polar bear births could plummet with climate change

Date:
February 8, 2011
Source:
University of Alberta
Summary:
Researchers have studied the reproductive ecology of polar bears in Hudson Bay and have linked declining litter sizes with loss of sea ice.

Researchers have linked declining litter sizes in polar bears with loss of sea ice.
Credit: iStockphoto

University of Alberta researchers Péter Molnár, Andrew Derocher and Mark Lewis studied the reproductive ecology of polar bears in Hudson Bay and have linked declining litter sizes with loss of sea ice.

Related Articles


The researchers say projected reductions in the number of newborn cubs is a significant threat to the western Hudson Bay polar-bear population, and if climate change continues unabated the viability of the species across much of the Arctic will be in question.

Using data collected since the 1990s researchers looked at the changing length of time Hudson Bay is frozen over (the polar bear's hunting season) and the amount of energy pregnant females can store up before hibernation and birthing.

An early spring-ice breakup reduces the hunting season making it difficult for pregnant females to even support themselves, let alone give birth to and raise cubs. Pregnant polar bears take to a maternity den for up to eight months and during this time no food is available.

In the early 1990s, researchers estimate, 28 per cent of energy-deprived pregnant polar bears in the Hudson Bay region failed to have even a single cub. Researchers say energy deprived pregnant females will either not enter a maternity den or they will naturally abort the birth.

Using mathematical modeling to estimate the energetic impacts of a shortened hunting season, the research team calculated the following scenarios:

If spring break up in Hudson Bay comes one month earlier than in the 1990s, 40 to 73 per cent of pregnant female polar bears will not reproduce.

If the ice breaks up two months earlier than in the 1990s, 55 to a full 100 per cent of all pregnant female polar bears in western Hudson Bay will not have a cub.

The polar-bear population of western Hudson Bay is currently estimated to be around 900 which is down from 1,200 bears in the past decade.

The number of polar bears across the Arctic is estimated to be between 20,000 and 25,000.

The research team says because the polar bears of Hudson Bay are the most southerly population they are the first to be affected by the global-warming trend. However, they say that if temperatures across the Arctic continue to rise, much of the global population of polar bears will be at risk.

The research will be published in Nature Communications, Feb. 8


Story Source:

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


Journal Reference:

  1. Péter K. Molnár, Andrew E. Derocher, Tin Klanjscek, Mark A. Lewis. Predicting climate change impacts on polar bear litter size. Nature Communications, 2011; 2: 186 DOI: 10.1038/ncomms1183

Cite This Page:

University of Alberta. "Polar bear births could plummet with climate change." ScienceDaily. ScienceDaily, 8 February 2011. <www.sciencedaily.com/releases/2011/02/110208112647.htm>.
University of Alberta. (2011, February 8). Polar bear births could plummet with climate change. ScienceDaily. Retrieved March 5, 2015 from www.sciencedaily.com/releases/2011/02/110208112647.htm
University of Alberta. "Polar bear births could plummet with climate change." ScienceDaily. www.sciencedaily.com/releases/2011/02/110208112647.htm (accessed March 5, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Thursday, March 5, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Late Winter Storm Wreaks Havoc Across Eastern US

Late Winter Storm Wreaks Havoc Across Eastern US

AP (Mar. 5, 2015) — A strong cold front moving across the eastern U.S. has dumped deep snow in some regions, creating hazardous conditions from Kentucky to New England. (March 5) Video provided by AP
Powered by NewsLook.com
Keurig Co-Founder Says Company Has A Waste Problem

Keurig Co-Founder Says Company Has A Waste Problem

Newsy (Mar. 5, 2015) — Keurig co-founder John Sylvan told The Atlantic he doesn&apos;t even own a Keurig because they&apos;re too expensive and produce too much waste. Video provided by Newsy
Powered by NewsLook.com
Raw: Tourists Visit Rare Grey Whales in Mexico

Raw: Tourists Visit Rare Grey Whales in Mexico

AP (Mar. 4, 2015) — Once nearly extinct, grey whales now migrate in their thousands to Mexico&apos;s Vizcaino reserve in Baja California, in search of warmer waters to mate and give birth. Tourists flock to the reserve to see the whales, measuring up to 49 feet long. (March 4) Video provided by AP
Powered by NewsLook.com
Raw: Injured Miners Treated After Blast

Raw: Injured Miners Treated After Blast

AP (Mar. 4, 2015) — An explosion ripped through a coal mine before dawn Wednesday in war-torn eastern Ukraine, killing at least one miner, officials said. Graphic video of injured miners being treated in a Donetsk hospital. (March 4) Video provided by AP
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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