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Squirrel v. Spruce

January 25, 2007

Seeds are the prize in an epic evolutionary struggle.


A struggle over seeds. I’m Bob Hirshon and this is Science Update.

It’s not as sensational as lions hunting gazelles or orcas catching seals, but the red squirrel and the white spruce are locked in an epic battle over seeds. Scientists thought the tree had found a winning tactic: starve the squirrels of seeds for several years and then produce a bumper crop just when its enemies’ numbers are low. But ecologist Stan Boutin of the University of Alberta says even that wasn’t enough.

STAN BOUTIN (University of Alberta):
The squirrel has countered this strategy by actually anticipating when the trees are going to produce the big amounts of seed and producing another litter of babies. So the squirrels have produced a counterstrike against the trees.

And as in all great epics, the protagonist’s downfall is of his own making. Boutin says the tree may reveal its intentions through the hormones in its buds.

I’m Bob Hirshon, for AAAS, the science society.