Rare black squirrels could become a more common sight in East Anglia, according to an expert who has mapped the spread of the rodent in the UK.

East Anglian Daily Times: Black squirrels are the same species as grey squirrels, the only difference being the colour of their fur Picture: Kevin SawfordBlack squirrels are the same species as grey squirrels, the only difference being the colour of their fur Picture: Kevin Sawford (Image: Archant)

Black squirrels in Britain are the same species as grey squirrels, with the only difference being their fur colour, and the latest study led by Dr Helen McRobie at Anglia Ruskin University (ARU), has shed new light on why some grey squirrels are black.

Working with colleagues from the University of Cambridge and the Virginia Museum of Natural History in the United States,

Dr McRobie has found that the faulty pigment gene in grey squirrels is identical to a faulty gene found in the closely-related fox squirrel, a species which is native to North America and also has black variants.

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DNA testing suggests it is highly likely the mutation first arose in the fox squirrel and passed to the grey squirrel through interbreeding. Dr McRobie said: "People have spotted 'mixed species' mating chases, with a mix of grey and fox squirrels pursing a female. The most likely explanation for the black version of the gene being found in the grey squirrel is that a male black fox squirrel mated with a female grey squirrel."

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East Anglian Daily Times: A black fox squirrelA black fox squirrel (Image: Archant)

Wild black squirrels living in the UK are believed to have originated from animals that escaped from a private zoo, having been imported from the United States. The first wild black squirrel was recorded in Woburn, Bedfordshire, in 1912, and they are now found across many parts of south east England, predominantly in Bedfordshire, Hertfordshire and Cambridgeshire.

"I carried out a citizen science project several years ago and there were one or two sightings from Norfolk and Suffolk but I wasn't able to confirm them," added Dr McRobie.

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"They have moved slowly northwards and eastwards over the past 100 years, so it wouldn't be a surprise if they started to colonise Norfolk and Suffolk in the future."

If you have seen a black squirrel in the region, you can let Dr McRobie know by e-mailing helen.mcrobie@anglia.ac.uk Please include photographic evidence if possible.