First it was just the red squirrel, then the grey – and then a third, the little-known black variety, was observed.
Now scientists have recorded a fourth type of squirrel living in the UK: a "brunette".
The creature's existence has come to light following a nationwide research project, launched earlier this year, which asked the public to report sightings of squirrels.
The brunettes, also known as "black-reds", are dark brown or black in colour but have the body shape of a red squirrel, with its distinctive tufty ears. They may have white markings, particularly on their stomachs.
Their discovery makes them the rarest of all the UK's squirrel varieties, with researchers unsure how many there may be. While populations of brunettes are established on the Continent, the researchers believe this is the first time they have been recorded in Britain.
We have lots of squirrels here.
In my area about 90% are black with the balance a mix or grey and red. Never seen brunettes here.
The proportions vary, you can travel a few miles and find mostly grey squirrels.
They have noisy territorial wars quite often and it's not uncommon for a "gang" to invade others turf. They usually destroy each others nests and kill any babies they find. This is done even within the same species. A family of blacks will often invade a neigboring family to drive them out.
At the heart of science is an essential balance between two seemingly contradictory attitudes--an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new.
This is how deep truths are winnowed from deep nonsense. -- Carl Sagan