Both are rich chestnut above and white below, although the stoat is generally darker. But they are easy to tell apart if you get a reasonable view.

Look first at the tail: stoats have longer, hairy tails with a black tip. Weasels have a short, thinner tail.

Stoats are larger: about 42cm including its tail, weasels are only 25cm. 

Both species are carnivorous and relentless hunters: the stoat mainly eats rabbit, stalking them and sometimes mesmerising them with their antics. Weasels favour voles and mice, often pursuing their prey down burrows. They both kill with a quick bite to the back of the neck.

The stoat used to change its coat colour in winter to its white state, known as ermine. The black tip remains. Around here this no longer happens and you would have to go to the mountains of Scotland to see this now.

They don't have it all their own way: both species fall prey to owls and hawks, and they are heavily persecuted in some regions because they take game-bird eggs and young.                                 

Stoat 

CAC