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Red squirrel, grey squirrel, black squirrel … ~ by Chris

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 of the chromosomes) that affect the production of melanin pigments (in the hair and skin).   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 1900’s, 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.  The black form of the squirrel is known in Canada and parts of the United States.






Posted in: Flora & Fauna ~ On: 30 May, 2008

31 comments so far

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

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.

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.

12 October, 2008

yes, i had heared that black squirrels were more aggressive and posing a threat to other squirrels, when i looked online for more information i was surprised to see that the daily mail came up before sources like wildlife or environment sites……………… also the daily mail seemes to focus more on the threatening, overruning aspect of these squirrels……….can’t help noticing parallels to other daily mail ‘news’ stories
Haven’t come accross any up north yet so good to hear what other people’s experiences are.

16 October, 2008

Some interesting news on the BBC web site, which suggests that red squirrels might be developing some immunity to the squirrel pox virus. See

14 November, 2008

As part of the Dundee squirrel survey I have had reports of two sightings of “black” greys squirrels in 2.5 years. One was near Springfield in North Fife and the other was in Dundee city itself. No sign yet of any population explosion. The city still has a fairly steady population of around 100 red squirrels mainly to the northwest. This is mainly due to the effort being made to contain the expansion of the greys.

10 December, 2008

iam a countryside managament student at duchy college iam doing a assingment on woodlands and things i think that these black ones thet might be good if they die down a few of the grey 1 then the native reds might a chance to reintroduce them selfs

28 January, 2009

I live in St Ives,Cambridgshire – black squirrels are common and seem to have been increasing over the last few years.
Are they mutants of the grey or have they been introduced into GB?

29 January, 2009

They seem to have arisen due to a change in the DNA , that is, a mutation
see http://www.cambridge-news.co.uk/cn_news_home/displayarticle.asp?id=309930
for a report on the squirrels in the Cambridge area.

4 February, 2009

Does anyone know of any sanctuary in Southern England that people, especially children, can visit and see red, grey and black squirrels?

8 February, 2009

They aren’t mutants, they’re decendants of the American black squirrel. Some cheekly black squirrel escaped from a zoo and banged a grey one.

12 February, 2009

Interesting !

7 October, 2009

I live up in the mountains in central portugal and have seen only 20 yards from my house, just into the forest, what can only be described as a black Red squirrel.

I have seen this creature twice now on the same tree. Its the size and shape of a Red Squirrel, tufted ears and is black,not jet black, just black although I now know it has a white bib, that is like that of a pine martin. It makes a really unusual sound as well. Very difficult to describe and it is incredibly shy. Is it possible that it is a black red squirrel and not a black grey squirrel??

24 October, 2009

i saw one in my garden. i live in sheffield it was clearly a black squirrel jus chillin on my garden fence

28 February, 2010

Apparently black and grey squirrels are the same species, but black has been observed to be the more dominant/stronger where the winters are colder. They expend less energy while dormant, and thus are stronger from the get-go. Studies done between Ottawa and Toronto, Canada, where both exist but in different ratios.

karen martindale
29 March, 2010

I too have seen black squirrels which are clearly red ones (I trap and shoot greys so I absolutly know the difference). Little tuffty ears, red shaped tail, smaller size. They are in several places I visit to look at reds in West Lancashire and Sefton.

barry page
27 April, 2010

Pretty sure I saw a red squirrel today, about a mile from my home in Burrington, Devon. Smaller than a grey squirrel, it was about 50 metres in front of me, but I couldn’t get any closer; eventually, it scuttled in to a hedge.

8 November, 2010

Hi barry page, I do hope it was a red squirrel but even if it was it will probably catch squirrel pox virus from the alien grey and die a painful death very quickly. However, Red Squirrels South West (RSSW) are hoping to reintroduce reds to the Isle of Purbeck soon and are hoping for support from as many people as possible.

15 June, 2011

Visiting my friend in Dundee, saw a black squirrel today!

27 July, 2011

was out with dog at 6am in ebrington when a black squrrel ran across the road. i have seen it in the same place 2 mornings running

9 November, 2011

I have seen a black squirrel running on my fence a couple of times this year (Bexley Kent)

16 June, 2012

I would disagree, respectfully, with Karen Martindale, judging by the photograph at the top of this article. This animal resembles the grey ‘tree rat’ squirrel and is probably going to be as successful as Sciurus caroliniensis. I would also venture an unscientific theory (?). Both black and grey squirrel have the adventurous and aggressive personality necessary for survival in an environment where arboreal denudation is accelerating. As an example of adaptation, the greys and probably the blacks have learned that certain actions will elicit a desire to give food in humans – they have learned to beg, thus increasing their food source. The shy red squirrel avoiding humans at all costs will not acquire this skill and thus miss out while facing a diminution of their own environment and source of food.

13 September, 2012

I googled ‘black squirel’ and came to this page—— I noticed one of these on our land in Portuguese pine forrest in the Serra do Acor, and was intregued to find out if it was indeed a squirel or not.

16 September, 2012

As Mike above says, I too came to this page to see if the black existed. I had seen a very feisty, chatty, aggressively behaved one in the pines as I was having the land fenced and some pines cut in the forest surrounding me 2 years ago. We were obviously disturbing its habitat. Noone believed there were black squirrels. My girlfriend now believes me as, as she was leaving the property today she disturbed one in the road next to the casa. I had thrown the soil and roots of potted cabbages into a deep rut in the road. It was obviously interested in it as a source of food. Oddly it did not run up the pine next to it but up the road and into the undergrowth. I live near Almoster in central Portugal.

15 October, 2012

As per Mike and Rodger, I too came across this page after viewing one. We have just got back from our house in Vendas, Nr Alvaiazere, Central Portugal. I heard aloud rustling in our pines and eucalyptus and there it was this strange kind of black, red, white bibbed pointy eared squirrel or whatever. It looks like they’re breeding rapidly in Central Portugal if your only a couple of villages away in Almoster, or is it a not a squirrel??

3 November, 2012

I live in southern Louisiana and these jet black squirrels are beginning to run rampant! I am also confused by some of the information above because our blacks are in fact much more hesitant and more calm than the usual greys I have grown up with, even had as a pet! Our hunters shoot to kill all during squirrel season but prefer greys due to blacks being a much grainier/tougher meat. (I can not eat them, I believe they are a mere step up from eating a rat (which here in Louisiana is done due to the overpopulation of nutria) Amazed I can’t find more localized information on this topic.

Rose Hymas
5 September, 2013

As per Mike, Ian and Rodger, I too came across this page after two viewings and not being sure what I was seeing ! We live in Chaos, very close to Alvaiazere and this is the first time in 7 years I have seen them.

5 September, 2013

They are thriving here in Portugal. They are a Black Red hybrid and they are everywhere. It leads me to believe from the comments that they may be inter species as they are definitely red crosses her; however if they can do that then they could cross with greys.

Gerry F D
25 September, 2015

You want to see squirrels! The greater Toronto area (GTA) has numerous squirrels. Parliament buildings and surrounding grounds are patrolled by the resident falcon to control them. They do provide an irresistible subject to photograph for the Japanese tourist and others.
My neighbourhood 20 miles west has numerous brown, grey and many black squirrels. Over four years of observing them I can unequivocally say the black squirrels are the more aggressive or at the least the cheekiest. They do not hesitate to come right up to the back door or patio table whereas the grey ones keep their distance. They also chase the the gray and brown squirills away although occasionally can be seen getting very cosy with each other.

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