The term 'certain weasel' refers to two species of small mammals, the ERMINE and the STOAT. The ERMINE is a type of weasel that has a white winter coat and is found in northern regions of Europe, Asia, and North America. The STOAT is also a type of weasel that is found in Europe, Asia, and North America and is known for its reddish-brown fur. Both species are members of the Mustelidae family and are known for their predatory behavior.