image: A North American red squirrel emitting a territorial vocalization called a "rattle." This image relates to a paper that appeared in the April 18, 2013, issue of Science Express, published by AAAS. The paper, by Ben Dantzer at Michigan State University in East Lansing, MI, and colleagues was titled, "Density Cues Trigger Maternal Stress Hormones That Increase Adaptive Offspring Growth in a Wild Mammal." view more
Credit: [Image courtesy of Ryan W. Taylor]