It is often difficult to use the mouse to target what ever is attacking you, even with fairly large attacker. If the attacker is small (coyote cub, mutant squirrel, etc.), the difficulty goes way up, If you have a large follower like a bear, it become impossible to target small attackers as they hide under the pet. Then again, there are the invisible revs.

If you can target something you can command your pet to attack and have a chance to hit back.