“Oh.” Twilight looked at the door. “Do you think it’s an instinct? Or is it a social behavior?” She floated up a scroll and began scribbling. “Predators often try to avoid leaving a scent trail; that’s one possibility. I can’t see a scavenger wanting to spend the effort, though. I suppose it could be a social pressure, but why would it have developed? Maybe we should observe him. There’s sight spells; I could cast one on the wall.” Her horn began to glow.