I agree that if he wandered off a good ways from the camp, the chance of a predator attack might be greater, but you still have to factor in all the initial noises that would have run them off in the first place.
Shortly after he vanished, you have the parents and grandad walking around screaming at the top of their lungs along the creek bed, the road, and the overgrown brushy areas. No animal in his right mind is gonna hang around with all of that going on.
After the searchers arrived, just about every animal over 5 pounds would have hightailed it for the hills, with the exception of some of the burrowing animals like skunks and coons. That was actually the intent of my post, get in there and find this kid before the bigger animals return to the scene. They WILL return, once it quietens down again.
Another phenomenon I haven't seen mentioned too much is echo's and sound distortion. Deorr may have gotten separated from his parents and could actually hear them calling for him, but due to the echo's created by the surrounding hills and outcroppings, it sounded to him like they were in a different area than they actually were. Unfortunately, as he continued to move in the direction of the sounds, he got further and further away.
Anybody that has ever camped around mountains and valleys knows that sound will bounce off of all kinds of things. It will sometimes make things seem much closer than they really are. Gunshots are a good example of something you will hear out in the forest that sounds as if it came just a few hundred yards away, when in reality, it may be some dude target shooting a 1/2 mile away from you. It sounds close, but it isn't. It's the sound distortion, echo's, and the differences in elevation that play tricks with you.
Most likely he would have been going cross-country on grass, leaves, and sticks, which eliminates footprints, or at least severely limits them. I think he may have headed up to a higher elevation, because to him, that's where it sounded like his parents calls were coming from.
