At this time of year stoats traditionally change the colour of their fur from brown to white but this is no longer a good survival tactic for them.
The colour change is governed by the stoat's pituitary gland which reacts to the cold weather and reduced hours of daylight. The white fur coat, known as 'ermine' has been highly prized for centuries by royalty, nobility and others for their showy (egotistical) costumes.
But for the stoat this white fur isn't for show - it's for snow. Having good camouflage in a snowy environment can make the difference between life and death.
However the changing UK weather conditions don't always work in the stoats favour. The fur-colour-changing-trick was a brilliant evolutionary strategy during the last ice age, but as each winter gets less and less snowy, the white fur becomes more of a hindrance. It's not just us dreaming of a white Christmas.
Fact is, a white stoat in an unwhite habitat sticks out like a porcupine at a nudist's colony. It can also hinder the stoats ability to hunt down food. Without snow the stoats dinner will see it coming a mile off. To compensate for this predicament stoats are re-evolving!
In the southern half of the UK where there is less snowfall they're becoming less white in the wintertime. They literally change to half brown and half white (see photo above). In the fashion world of the stoat brown is the new white. If winters keep getting warmer then stoats in ermine could become extremely rare.