Can't believe some people are claiming the parents aren't in the wrong by mentioning that children sometimes escape supervision. And yes, look what happens when they do! If your child is running around next to a bloody Gorilla enclosure that he/she could easily get into, I'd think it'd require only a minimal amount of common sense to see that they need extra special supervision in that area. It's kind of like if you are next to a really busy road, you can't say it's not the parents fault for letting them run into oncoming traffic just because "they sometimes escape supervision".
I do agree that the Gorilla wasn't protecting him, but he shouldn't have been in there in the first place! The gorilla was only doing what it knows, and no one will ever really know his intentions. He might have thought that was acceptable for an infant of his species but wouldn't know any better with a human one.
Another thing I'm wondering, I've only seen the video of the enclosure but it looks like there's a massive cliff overlooking it, did the kid actually fall down that or was there another way in? If so, more to back up my first point...