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11 Dec 2006 09:42
Squirrels hit the genetic lottery with their chubby cheeks and bushy tails. It’s hard to imagine picnickers tossing peanuts and cookies at rodents if they looked like rats.
But good looks alone don’t get you through Chicago winters.
Nor do they help negotiate a treacherous landscape of hungry cats, cars and metal traps.
So how do they do it? And what does all that searching, huddling, darting and forgetting where they hid their nuts mean? Joel Brown aims to find out.
“We’re trying to get a glimpse of what your life is like if you are a city squirrel,” said Brown, a biologist at the University of Illinois-Chicago.
He and a team of students will trap squirrels in Chicago and its suburbs this winter, taking skin samples for DNA analysis.
While the methods aren’t unlike those used to study animals in exotic lands, little attention has been paid to those in human neighbourhoods. It is, after all, a lot sexier to track gorillas in Africa than a squirrel on Main Street.
“Our appreciation is least in our own backyard,” said Brown, who is part of a small brethren of scientists around the country who have made it their business to figure out how squirrels go about theirs. What they’ve discovered is that the critters are downright crafty.
Start with their attitude toward other squirrels’ food. They want it and won’t hesitate to steal it.
To ward off thieves, squirrels engage in a shell game: they go through the motions of digging and pretending to jam acorns into the ground, even smoothing out the grass to make it appear as if they’re covering their hiding spot, before running off with the acorns still in their mouths.
“What possible purpose could that be for other than fake out somebody watching them bury it?” said Peter Smallwood, a University of Richmond biologist.
Squirrels figure out how to outsmart devices designed to keep them away from food—something naturalist Howard Youth learned the hard way. Squirrels broke into four types of bird feeders in his Maryland yard before he found one that they couldn’t penetrate—so far.
“They will try something new and eventually, if one gets it, the other ones will notice and they will figure out a way to thwart the bird feeder,” Youth said.
Brown hopes to get into his subjects’ little heads. One way is by setting out hazelnuts that have been shelled alongside those that haven’t. “If they pick hazelnuts with shells it means they’re looking more toward the future and not in need of food right now,” he said.
If they pick shelled hazelnuts, “it means they’re living pay cheque to pay cheque”.
Squirrels know the difference between acorns that can be stored for a long period and those that can’t. If they only have access to those that can’t, “they will scrape out the tiny embryo and that kills the seed [so] it stores well”, said Michael Steele, a wildlife biologist at Wilkes University in Pennsylvania.
But squirrels have their shortcomings. Sometimes they forget where they buried their nuts, although Brown said their sensitive noses allow them to sniff out ones hidden by their neighbours.
And while someone once swore to Brown that squirrels look both ways before crossing the street, they’re apparently looking for something other than cars.
Robert McCleery, who completed his dissertation at Texas A&M on urban and suburban squirrels, outfitted squirrels with radio transmitter collars and found that 80% of them died under the tyres of a car or truck.
Still, who cares about squirrel habits besides a small band of scientists? Lots of people.
Search for “squirrels” on the internet, and websites such as “Squirrel Lover’s Club” and “Scary Squirrel World” pop up. There are sites that allow readers to comment on stories like the one from Russia about a “pack of furious squirrels” that reportedly tore a dog to pieces.
Another site, “The Campus Squirrel Listings”, judges colleges by their squirrel populations. The United States Naval Academy and the University of California, Berkeley, are among the top schools.
None of this squirrel fascination surprises Brown. “They are the clowns in your backyard,” he said.—Sapa-AP
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