Is it true that sheep is the dumbest creature from all?

I have seen some movie and books and they said that sheep is the dumbest creature from all creature,or at least from all warm-blooded creature. They will not scream for help while they’re attacked,they won’t try to attack their predators,they will remain silent and will not fight while they’re eaten alive by predators,etc. Unlike sheep,goats,as their close cousin will do the opposite behaviors.

Can someone enlighten me about this simple matter?