Weasel appears to have the instincts and displays the behavior of an actual weasel (licking a prison grate due to not knowing what it is or thinking it might be food, slowly slinking around with his back hunched as if walking on two legs is uncomfortable). If this is the case, Weasel has a very one-track mind, is easily agitated and startled, is scared by and doesn't want to do many things, and doesn't understand or care for social norms and how people see or think of him (this last point is confirmed by the aforementioned licking of the grate)