This is not the very old joke about the difference between the two! Seriously, how do you tell the difference? We have one or the other that plays in the field next door, sort of leaps about and chases it's own shadow, very cute, but I don't know which it is.
If it would keep still long enough I might be able to see it's tail properly. Don't think it has a black tip. It's got a white chest, does that make a difference?
Weasels are quite tiny and if you see them running they sort of bring their back legs to the front so their body sort of forms a hump. A bit like the movement of a caterpillar. A stoat is bigger and runs like a ferret
Miss-Ladybug, they're all different. They're all members of the same family, but ferrets are domesticated, unlike polecats, which are wild. Stoats are slightly larger than weasels and have a black tip to the tail (as already mentioned) - they are called "ermine" in winter, when they turn white in the north of the country, that's where the ermine on judges' robes comes from! Weasels are small and chestnut-coloured and don't change colour in the winter.
Got to disagree with annlinda. If it has a white chest and from the description of it's action it is a stoat. Weasels are not the playful sort, being to intent on feeding. But stoats play about all the time. A stoat looks like a mobile pencil and not much bigger.
Oh I'm even more confused now! It definitely moves like Annlinda's weasel description, but it's playful that's for sure. It was leaping in the air trying to catch a butterfly yesterday evening, probably wanted to kill it I know, but looked brilliant, wish I had a really good camera.