It sounded like they'd dragged the reservoir and felt confident he hadn't gone in, although his scent was marked in that general area and that was the place they concentrated their search. I don't know how truly certain you can be about water (I'm unclear on whether it's just an independent reservoir or whether it's connected to a larger waterway that he could have been swept into), but it sounded like they'd moved on with their search. As for wild animals, initially they were saying that there weren't any tracks nearby and they didn't think that likely.
However, the latest update says that they're moving the search away from the campsite, and it sounds like they are starting to think more and more that either a person took him or a wild animal did, so perhaps the lack of tracks didn't necessarily eliminate animals. They said they've had 300 searchers for over a week and that while they're leaving a small force there, they really don't think he's in the search radius.
I almost find myself hoping that somebody took him, because otherwise I don't see how he could be alive.
Either way, I'm praying that he's found soon. A week is right about the time that, if somebody did take him, they will probably start to relax and have him out, and an acquaintance might notice a little boy who has suddenly appeared.