Red squirrel, grey squirrel, black squirrel …
Once upon a time, we only had to worry about the impact of the imported grey squirrel on our native red squirrel (see blog http://www.woodlands.co.uk/blog/conservation/red-squirrel-grey-squirrel/ ). However, it now seems there is another player on the scene: the black squirrel. Whereas red and grey squirrels are two distinct species, Sciurus vulgaris and Sciurus caroliniensis, black squirrels are variants of the grey squirrel. The difference between the two is largely due to a change in the gene (a specific sequence of nitrogenous bases in the DNA) that affect the production of melanin (hair and skin) pigments. The black squirrel has lost a piece of DNA associated with these genes. As with most genes, the melanin genes occur in pairs. If the squirrel has one damaged gene, then the animal has brown-black fur. If, however, it has two copies of the damaged genes then it has a glossy, jet- black coat.
Some of the first sightings of black squirrels date back to the early 1900s, but in recent years, they have become more common in parts of Hertfordshire and Cambridgeshire. It has been suggested that the black form has higher levels of the male hormone, testosterone, and is, therefore, more aggressive in seeking a mate and establishing territory.
http://www.guardian.co.uk/environment/2008/apr/26/endangeredspecies
http://www.cambridgenews.co.uk/cn_news_home/displayarticle.asp?id=30990
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3 comments so far
max
24 June, 2008
Any one else think that these black squrril mutants are just the next step in squrril evolution and should be left to over run any species that cant out compete them
Del
24 June, 2008
very interesting, thank you for the information I was wondering about this as I saw a little information in teh national newspaper awhile ago, Not heard or seen any in the Devon area as yet, unless you know otherwise.
Kailah
9 September, 2008
We live in Hertfordshire and have both grey and black squirrels that live and have bred in and around our garden. We provide regular food (nuts) for all of them and see them regularly interacting.
What has surprised me about this and other articles is the comment that the black squirrels are the more agressive of the two. We have found it to be the exact opposite; it is always the greys who are chasing out the blacks and establishing their territory. We also find the blacks to be more timid and nervous, whereas the greys appear much braver and more curious.