Clairvoyant Squirrels? Not So Nutty

Scientists have found that spruce seed production leads some squirrels to produce more young

• Hannah Schardt
• Apr 01, 2007

A NEW STUDY finds that two species of squirrels can predict when local spruce trees are about to produce an extraordinarily large amount of seed--their primary food source--in an event known as "masting," and can take advantage of the abundance by giving birth to additional young. Lead author Stan Boutin of the University of Alberta first noticed the phenomenon in 1993, when many of the red squirrel females he was tracking in the Canadian Yukon produced larger litters than normal, then birthed a second litter just weeks later--all but unheard of for the species--right before a masting event.

The researchers aren't sure how the squirrels are able to predict the overabundance, which occurs irregularly. Many other animal species will produce additional young after they see a bumper crop of a food source, says Boutin, "but it's much better to anticipate the resources before they come." As Boutin was preparing his study for publication, he heard of another study that duplicated his findings with a distinct species of European red squirrels, and the two studies were jointly published in the journal Science.