Featured Research

from universities, journals, and other organizations

When it comes to survival of the fittest, stress is a good thing, squirrel study shows

Date:
April 18, 2013
Source:
Michigan State University
Summary:
Researchers have shown for the first time how females' use social cues to correctly prepare their offspring for life outside the nest. The results confirm that red squirrel mothers boosted stress hormone production during pregnancy, which increased the size and the chances of survival of their pups.

When the woods get crowded, female squirrels improve their offspring’s odds of survival by ramping up how fast their offspring grow.
Credit: Courtesy of Ryan W. Taylor

When the woods get crowded, female squirrels improve their offspring's odds of survival by ramping up how fast their offspring grow.

Related Articles


In a study led by Michigan State University and the University of Guelph (Canada), researchers showed for the first time how females use social cues to correctly prepare their offspring for life outside the nest. The results, published in the current issue of Science, confirm that red squirrel mothers boosted stress hormone production during pregnancy, which increased the size and the chances of survival of their pups.

"Natural selection favors faster-growing offspring, and female red squirrels react accordingly to increase their pups' chances of survival," said Ben Dantzer, formerly with MSU's zoology department and now a postdoctoral researcher at the University of Cambridge (United Kingdom). "Surprisingly, squirrels could produce these faster growing offspring even though they didn't have access to additional food resources."

Proving that food availability isn't always the universal variable affecting population dynamics took a true team effort. It was equal parts field physiology, experimental ecology and longitudinal studies of natural selection that led to these findings, he added.

The team based much of its study on the Kluane Red Squirrel Project, a 22-year-long study on North American red squirrels living in the Yukon led by researchers from the University of Alberta (Canada), Guelph and McGill University (Canada). Out in the field, researchers used recordings of territorial vocalizations, or rattles, to create the illusion of a big population of squirrels.

Females reacted to the increased commotion by producing more stress hormones while pregnant and their pups grew faster. Dantzer, along with Amy Newman of the University of Guelph, also manipulated stress hormone levels in mothers to conclusively show that stress hormones were the cause of the faster growth rates of their pups.

"Despite the widespread perception that being stressed is bad, our study shows that high stress hormone levels in mothers can actually help their offspring," Dantzer said.

The research also showed that these changes were immediate rather than happening over multiple generations, said Andrew McAdam of Guelph University.

"When population density is high, only the fastest-growing offspring survive," said McAdam, who supervised Dantzer when they both were at MSU. "Our study also showed that rather than simply exhibiting lagged responses to environmental changes, the red squirrels may anticipate environmental changes using cues they pick up on during pregnancy."

The squirrels then are able to make adjustments in their offspring, allowing the pups to better survive, he added.

While researchers found that female squirrels could use hormones to help the early survival of their offspring, the pups may not be so lucky in the long-term. Offspring born during these high-density years don't live as long. This suggests that their successful early sprint burns a few matches that would have helped them in the marathon of life.

Additional researchers who contributed to this paper include: Rudy Boonstra, University of Toronto; Rupert Palme, University of Veterinary Medicine (Austria); Stan Boutin, University of Alberta; and Murray Humphries of McGill University.

The research was funded in part by the National Science Foundation.


Story Source:

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


Journal Reference:

  1. Ben Dantzer, Amy E. M. Newman, Rudy Boonstra, Rupert Palme, Stan Boutin, Murray M. Humphries, and Andrew G. McAdam. Density Triggers Maternal Hormones That Increase Adaptive Offspring Growth in a Wild Mammal. Science, 18 April 2013 DOI: 10.1126/science.1235765

Cite This Page:

Michigan State University. "When it comes to survival of the fittest, stress is a good thing, squirrel study shows." ScienceDaily. ScienceDaily, 18 April 2013. <www.sciencedaily.com/releases/2013/04/130418142302.htm>.
Michigan State University. (2013, April 18). When it comes to survival of the fittest, stress is a good thing, squirrel study shows. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/2013/04/130418142302.htm
Michigan State University. "When it comes to survival of the fittest, stress is a good thing, squirrel study shows." ScienceDaily. www.sciencedaily.com/releases/2013/04/130418142302.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
Powered by NewsLook.com
Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Feast Your Eyes: Lamb Chop Sent Into Space from UK

Feast Your Eyes: Lamb Chop Sent Into Space from UK

Reuters - Light News Video Online (Nov. 25, 2014) Take a stab at this -- stunt video shows a lamb chop's journey from an east London restaurant over 30 kilometers into space. Rough Cut (no reporter narration). 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:

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