What are grey and black and red all over?

We’re all familiar with that beloved British icon, our native red squirrel, now sadly endangered. We’re also very familiar with its cousin, the grey squirrel, which is largely responsible for the red squirrel’s downfall. Greys are a North American animal, introduced as an ornamental species in English country estates in the 1820s. They have since taken the country by storm and now vastly outnumber our red squirrels. They carry a disease, squirrelpox, which our reds are susceptible to, and are also able to eat hazelnuts while they are unripe, something reds can’t do.

red squirrel
red squirrel

But now the domination of the grey squirrel is under threat. Or at least, that’s how it might look. Because there’s a new squirrel in town, and it could be coming to a place near you.

The black squirrel.

Yes, that’s right. It’s a squirrel, and it’s jet black.

With a population of perhaps 25,000-30,000 in the UK, the black squirrel population is still smaller than that of our red squirrels, but it is growing. Originally confined to the Letchworth area, it is starting to become the most common colour of squirrel you will see in some areas of Cambridgeshire and Hertfordshire.  Look online and you’ll see lurid newspaper headlines about black squirrels being ‘faster’ and ‘more aggressive’ than our greys. Like many such attention-grabbing headlines, they are completely wrong. Because research has shown something unexpected about our grey and black squirrels.

They are exactly the same animal.

DNA analysis has shown them to be the same species. So why have our greys suddenly started turning black?

black-coloured grey squirrel
black-coloured grey squirrel

The answer turns out to be down to a single squirrel.

In the USA, grey squirrels mated with another closely-related North American squirrel, the “fox squirrel”. Ironically, the fox squirrel typically has a reddish-grey colour and looks as though it is the offspring of a red and grey squirrel pairing. But at some point, a mating between a grey squirrel and a fox squirrel produced a genetic defect. A part of the grey squirrel’s colour gene went missing, turning it from grey to black. So now we have a population of black grey squirrels in North America.

Enter the private zoo collectors again. It is believed that a single squirrel with the mutation was brought into a private zoo in the Letchworth area in the early 1900s. It escaped into the local grey squirrel population, and the gene defect started to spread as more and more grey squirrels bred with black grey squirrels. There are as many theories about why the black gene defect is becoming dominant as there are researchers studying it, but the truth is that nobody is quite sure. But it is spreading, although many of the offspring of grey/black pairings are still grey, so we will not be losing our grey squirrel anytime soon. Grey greys and black greys seem able to co-exist perfectly happily

So there you have it.  And this is your chance to set a really evil question for your next pub quiz: what are grey and black and red all over?


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