I was asked recently about black squirrels seen regularly in a village near Cambridge. This is not an unusual question locally. They are individuals of the grey squirrel in which excessive quantities of the black pigment melanin are deposited in the hair. Close examination of the silver-grey fur of a "normal" grey squirrel shows that each hair is a mixture of black, white and brown. In melanic individuals, black dominates. Black squirrels are very rare over most of Britain but they are more frequently spotted in the counties of Bedford, Buckingham, Hertford and Cambridge, where they may be descendants of some black squirrels introduced at Woburn Park in Bedfordshire. White grey squirrels also appear from time to time, mainly in Kent, Surrey and Sussex. There are also records of red or erythristic grey squirrels, whose fur is mostly reddish-brown. Such squirrels are freak products of a genetic aberration. However, the squirrel that gave me the most excitement was one that I took to be a red squirrel. This was about 50 years ago, when our native red squirrel was more widely distributed and there was a chance that one could be seen in our district. I was misled, at a distance, by the summer coat of the grey squirrel, which has a brown suffusion in the grey of the back and more marked chestnut on the flanks and limbs. I am not the first person to have been confused by reddish grey squirrels. They have led to reports of the red and grey species interbreeding.
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