- Least Weasel Mustela nivalis Occupying most of Canada with the exception of the Maritimes, southern Ontario, and Quebec, this fierce little carnivore is scarcely larger than the mice on which it preys. Its total body length seldom exceeds 20 cm. Incredibly quick and agile, these tiny predators are seldom trapped except by accident. The coat, which is brown above with a white underside, turns ...www.nature.ca/notebooks/english/lestweas.htm