Red squirrels living in Canada’s Yukon territory can have a pretty hard knock life. Bitterly cold winters, resource scarcity, intense competition for habitat, threats from large predators like the Canada lynx, and even take big reproductive risks for their genetic fitness. All of these stressors take their toll on these resilient rodents. Their early life struggles can also leave a lasting mark. The more challenges young red squirrels face in the year they’re born, the shorter their adult lifespan. The findings are detailed in a study published April 24 in the journal Proceedings of the Royal Society B: Biological Sciences and could have some implications for humans.
Food booms
Red squirrels are about 11 inches long and weigh just over half a pound on average. They are known for their rust colored fur and “scolding chatter” above the trees. The new study uses data collected by the Kluane Red Squirrel Project, a multi-university long-term field study. The project has tracked and studied thousands of wild North American red squirrels in the southwestern region of the Yukon for more than 30 years that individually tags and tracks individual red squirrels to learn how they deal with all that’s thrown at them .
The new study analyzing the observations found that red squirrels that survive past their first year go on to live about 3.5 years on average. However, early life adversity like food scarcity can cut their life expectancy by at least 14 percent.
[Related: A Medieval strain of leprosy is infecting squirrels in the UK.]
“The ecosystem red squirrels inhabit in this region is unique,” study co-author and University of Arizona ecologist and evolutionary biologist Lauren Petrullo said in a statement. “Every three to seven years, their favorite food–seed from cones of white spruce trees–is produced in superabundance during what we call a food boom.”
The team found that even though these food booms are rare,…
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