The University of Alberta study, conducted jointly with Michigan State University, the University of Quebec-Rimouski and Claude Bernard University in France, found advantageous factors such as food availability and spring temperature experienced between birth and weaning could reflect later on each squirrel's lifetime fitness, longevity and reproductive success.

University of Alberta Professor Stan Boutin, co-author of the study, said the researchers used 15 years of data from a North American red squirrel population study. The scientists discovered female babies born into fortunate circumstances with more food, warmer spring weather and a lower population, experienced long-lasting positive effects on reproductive success, producing more offspring during the remainder of their lives.

In contrast, squirrels born into rougher circumstances with less food and bitter weather conditions didn't live as long and tended to wean fewer youngsters.

The study was published recently in the Journal of Animal Ecology.