A friend of mine has a cat that hisses and scratches people he doesn't know. This is a sign of fear. Other signs of being scared for cats are: ears flat back leaning backwards dilated pupils fluffed out tail "trying to get away" (flight or fight) (most species have this including humans) Signs of being scared for dogs includes, but not limited to: ears flat back leaning backwards trying to "get away" barking while backing up growling showing teeth tail is tucked underneath