Drejk |
Creatures lacking intelligence score cannot be trained like those with animal intelligence so they will be unable to perform tricks like trained mount. On the other hand they don't require combat training like living horses because they are not naturally afraid of combat, noise, etc. They still be able to follow simple commands issued by their creator/controller, such as "attack", "stop", "move".
Midnight_Angel |
Whether riding an animal, an intelligent being, an undead or a construct: the skill you require remains Ride.
One could argue that for riding a machine (construct or non-intelligent undead), you'd need a piloting skill, instead... but since there is no such skill in PF, you'll have to stick to Ride.