NOT EVERYTHING IS GOING EXTINCT

Washington Post - Because the history of Washington has been written by humans, nobody has paid much attention to the fact that 18 Canadian squirrels were released at the National Zoo during the presidency of Theodore Roosevelt.

But, if the capital's story were ever told by its rodents, few events would be more prominent than this one.

That's because those 18 squirrels -- whose coats of lustrous black set them apart from the native animals -- were the beginning of a shift that has changed the complexion of Washington's backyard critters. Now, probably because of a slight evolutionary advantage conveyed with a black coat, the descendants of these squirrels have spread all the way into Rockville and Prince William County. . .

Scientists say it's a real-life example of natural selection at work, which has rolled on for a century here without much public notice.

"It shows the spread of a gene within a population," said Richard W. Thorington Jr., a Smithsonian Institution researcher working on a book that includes a history of the District's black squirrels. "That is evolutionary change before your eyes.". . .

Some have been spotted in a forest 35 miles from their origins in Washington.