Same critter, different season! A brown coat for summer and a white coat for winter - it’s dependent on temperature though, so some stoats in warmer regions end up with brown or patchy white coats in winter instead!
[ID: an illustration of two stoats on a green background, surrounded by simple plants. One has a summer coat - brown with a white underbelly, and is positioned at the top in a curved position. The other has a winter coat - white with a black tail tip - and is positioned at the bottom, curled up to form a circular composition with the first stoat. End.