Researchers from the University of Alberta in Canada and the University of Sheffield in Britain studied a population of red squirrels for three years near Kluane National Park in southwest Yukon.

They discovered that when female red squirrels chose a mate to copulate with, genetic relatedness didn't play a factor.

"In males, the benefits of multi-female mating are well established, but in females the benefits of having many offspring is limited, making the reasoning for multi-male mating more puzzling," said Jeffrey Lane, who conducted the study while obtaining his doctoral degree at the University of Alberta.

The researchers said they also found relatedness of parents had no effect on the neonatal mass and growth rate of their offspring.

"Detailed investigations into the social and genetic context of multi-male mating in red squirrels and other mammalian species should help to provide insight into the evolution and maintenance of this behavior," said Lane.

The study appears in the journal Animal Behavior.