The mustelids are a group of mammals which in the UK include badgers, otters, polecats, stoats and weasels. Of these the greatest problems with identification seem to be how to tell a weasel from a stoat and so I thought a few pointers may come in useful.
Fortunately once you know the differences between these otherwise superficially similar animals it is actually quite easy to tell them apart though of course you have to remember which one is which!
Weasels are surprisingly small mammals despite their fearsome reputation as talented hunters of small rodents. They typically reach a body length of around 8 inches long and in cross section are rarely larger than a mouse. The general shape is one of a small, long, wavy mammal with a short tail.
Weasels are carnivores like stoats and will eat anything they can catch which often means small rodents like mice and voles. Their small body means they struggle to catch anything larger but it also means they are able to follow their prey into tiny holes where a mammal like a stoat would struggle to fit.
Weasels may be seen in a range of habitats including woodland and wild meadows and I even saw one last year hiding under a bush in a National Trust garden as dozens of visitors unknowingly walked within a couple of feet of it.
Stoats are much larger than weasels and may grow to become the size of a small adult ferret with a body length around 16 inches. The tail is also a very useful tip for identification because unlike the weasels it typically has a black tip on it.
In my experience, while I have seen both mammals on many occasions the stoat, being rather larger and bolder, is far more likely to be seen.
In addition the stoat’s larger size means it is able to take correspondingly larger prey with rabbits being well within it’s reach. This means they may be seen hunting on open grassland sometimes and if you are downwind of them you can watch their amazingly quick and acrobating hunting technique.
In photographs these two mammals appear very similar indeed but remember the old adage of a “sizable stoat and a wee weasel” to remember that the stoat is much larger and keep an eye out for that black tail. Those two elements combined are normally enough to safely identify these mammals even at a glance, such as when one ducks across a footpath in the countryside some distance ahead of you.