Rats: Intelligence.

Peter D. Sealey: "Rats. I don't want to sound like a dummy here. They're not smarter'n me."

Fret not, my friend. I wouldn't done thunk nuttin' o' the sort.

Commentator: "Despite centuries of fear and loathing, rats have proven themselves to be amongst the most intelligent creatures on earth."

Why is it that whenever someone says "Rats are intelligent" they have to prove their point by mentioning that they are smart because they are trainable, usable, manipulatable, by humans? Immediately after this comment, Samantha is busy proving how intelligent rats are by showing the viewers that one of her rats can nudge a ball with his nose so it rolls down a ramp and hits some pins. Heck, from the sound of it, she probably fed that rat to a snake because he missed some.
Rats are smart but not because they do what we want them to do. They're smart because they're resourceful. Any time, anywhere, they manage to survive. Proof that rats are smart: They're everywhere!