Animals do not need to cook their food because they are eating fresh meat. If you were to go out and kill a deer, you can eat the fresh meat straight off the deer and not have any problems, provided the deer isn't diseased (in which case the animal that would have killed and eaten it would have problems as well). However, the meat you buy from a grocery store has been handled by many people and processed and carry salmonella and other harmful bacteria that will make you sick, therefore you must cook it to the correct internal temperature to kill the bacteria. If you were to feed your pet raw meat from a grocery store, they will get sick but if you feed them fresh meat that you would eat they would be fine. Also, I think it would be hard to make a fire without opposable thumbs :)