St Bernard is a rarely used pet -- it has a ranged attack and decent HP pool but it doesnt really fit a niche (not the best ranged dmg, not the best attack, not the best HP) that isn't better accomplished by another pet type.
Suggestion: Consider making St Bernard have a standard (non-mana consuming) ranged attack. A pet that can stay at range indefinitely, without the same burst potential as rabbits, could make it a more viable pet option.