An Ermine is another name for a weasel when it’s white.
A weasel, normally brown in color, sheds its fur and grows a new winter white coat, and subsequently undergoes a name change in most parts.
Especially in the fur industry, where “ermine” sounds more glamorous than “white weasel.”
Sometimes “ermine” refers to the stoat, which is a small predatory mammal of the family Mustelidae.
The stoat was introduced into New Zealand in an unsuccessful attempt to control the rabbit population.