Id a friend who during her driving test hit a cat who landed on the bonnet, she kept driving and pulled in when safe to do so, cat shook itself and ran off unharmed, instructor stopped test there and then and passed her saying that if she'd stopped for the cat she would have failed immediately.
So you dont stop for dogs OR cats - the rationale being that you could cause an accident by stopping suddenly or swerving to avoid a dog or cat and end up harming a human being - and the life of a human being is deemed as more important than a cat or dog.