Social Warmth

Striped skunks use different strategies to get through long, cold winters in northern climates. While most male skunks den underground alone during the winter, a group of female skunks will often snuggle together with one male in communal dens.

Skunks that choose to go it alone reach torpor--the state during which an animal reduces its metabolism and lowers its temperature to save energy and conserve water--almost ten times more every day, a new study found.

Researchers were surprised to find that male skunks that huddle with females do not enter torpor at all, perhaps staying physically alert to defend the den.

"Contrary to our predictions, grouped skunks did not regularly use torpor in addition to huddling to maximize energy saving," write the authors. "Our results revealed a different strategy for animals in groups: When skunks were in groups they apparently benefit from huddling to the point of reducing the need to undergo torpor."

Huddling in groups minimizes the proportion of exposed surface area and water loss to the environment. Communal skunks emerge in the spring with a higher body fat percentage.

Male skunks that huddle with females also benefit reproductively, as studies have shown that low body temperature can lead to difficulties with sperm production. The downside: there is a higher risk of disease transmission in communal dens. Predator detection and depletion of resources are also a risk.

"The fitness benefits of spring body fat are probably higher in females than males because of higher reproductive cost incurred by females for pregnancy, parturition, and lactation," the authors explain. "Thus, the benefits of communal denning in females outweigh the cost, whereas for males the cost of communal denning must outweigh the benefits of higher body fat in the spring."

---LiveScience Staff

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Credit: Yeen Ten Hwang