Squirrels and Spruce Boom and Bust

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Squirrels and spruce boom and bust. According to a new study published in Science on 21 December 2006 (DOI: 10.1126/science.1135520), spruce trees in the Canadian Yukon, and parts of Belgium and Italy, have evolved a synchronized boom and bust approach to seed production in an attempt to thwart Red Squirrels (Tamiasciurus hudsonicus,) that feed on their seeds. Yahoo News (UK/Ireland) calls it "an evolutionary battle of wits for the survival of the species" between the spruce trees and the squirrels, and reports that "the phenomenon, known as masting, involves all of the trees in large regions synchronizing seed production so that they either produce massive amounts of seed, or no seed at all, in a given year."

Since the number of seed-bearing cones produced by one tree can vary dramatically, from 500 cones one year to 10 the next, the squirrel population will therefore be well fed one year, and starve the next, thus reducing the number of seed predators, allowing more seeds to survive. But research challenges this conventional evolutionary explanation. Researchers periodically captured and recaptured tagged squirrels to assess how many female squirrels were pregnant. At the same time, they recorded the number of cones produced by spruce trees in the squirrels' habitat. "Squirrels can somehow predict which years trees will produce massive amounts of seed, a new study reveals. The animals produce an extra litter of pups months ahead of these unusually large harvests."

According to Andrew McAdam of Michigan State University, one of the scientists involved in the study, "the reason it's so interesting is that we often think of seed predators, such as these squirrels, as going along with the trees' game." He explains that "this is the first time that this type of anticipation has been documented in animals such as squirrels." Scientists have not determined how squirrels can predict the size of the spruce cone harvest almost half a year in advance, but suggest perhaps the animals can detect higher levels of certain hormones in the cone buds that appear on trees a year before the large harvest. Perhaps they notice more of these cone buds in the spring ahead of the harvest and have an extra litter based on this visual cue. The Yahoo report concludes that the squirrels are beating the spruce trees in the "battle of wits."

Editorial Comment: Winning at games or wars requires superior strategies planned well in advance. The victor is the one who best anticipates the opponent's most likely moves, and develops the most effective counter-measures. Squirrels certainly have intelligence, and their collective survival strategy is clever. That is not proof that squirrels evolved, but it is proof that the squirrels brain is capable of solving such problems. Trees, on the other hand, are clearly not intelligent, therefore any "behaviour" used by spruce trees to defeat predators must rightly be attributed to their Designer, who created them on the third day as food for creatures such as squirrels (Genesis 1:11-13). Since both spruce trees and squirrels still survive, the score must be even.

Evidence News 9 February 2007

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