Even Greener Pastures

The Wikipedia says,

Definitions of the word 'weasel' that imply deception and irresponsibility include: the noun form, referring to a sneaky, untrustworthy, or insincere person; the verb form, meaning to manipulate shiftily;[6] and the phrase "to weasel out", meaning "to squeeze one's way out of something" or "to evade responsibility".[7]

If it is true, it' funny. Because this role is often by fox in Japanese. Foxes often deceive human in the old Japanese tales. They are smart enough to make fun of human. And weasels are probably described just like as little brothers of foxes and they also deceive human but they are not so nasty in Japanese stories.