Weasels /?wi?z?l/ are mammals forming the genus Mustela of the Mustelidae family. They are small, active predators, long and slender with short legs.
Weasels vary in length from 173 to 217 mm (6.8 to 8.5 in),females being smaller than the males, and usually have red or brown upper coats and white bellies; some populations of some species moult to a wholly white coat in winter. They have long, slender bodies, which enable them to follow their prey into burrows. Their tails may be from 34 to 52 mm (1.3 to 2.0 in) long. Weasels have a reputation for cleverness, quickness and guile.
Weasels feed on small mammals, and have from time to time been considered vermin, since some species took poultry from farms, or rabbits from commercial warrens. They occur all across the world except for Antarctica, Australia, and neighbouring islands. People have trained dogs to sense when a weasel is nearby. When detected, the dog will chase after it and kill the weasel. The benefit of this is to protect chickens and small mammals.