Did he really invade their territory? I mean, he was still away from them and behind a fence. It wasn't like he got up in the chimp's face and was trying to fight him.~A physical anthropologist appears~
You know, I feel like humans tend to feel or think that other animals do not kill for sport. That we're the only animals that kill our own kind... NOT. Chimps do kill other chimps and sometimes for no reason but to dominate. When chimps are in groupings, they tend to attack the the lone wolf. It's what they do and they have always done it.
This is why I am so AGAINST people have primates as pets (I know this isn't the case). They can be so unpredictable at times and at the end of the day, it's an animal. The man should have been behind some glass or something.
Maybe the chimps felt like their territory was being invaded? They tend to attack and kill under those circumstances. Who knows, it's not like we can sit down and have some tea with the chimps that attacked him.
 Ahhh, I read the article. He DID invade their territory. That is a big no-no. Chimps kill for territorial purposes. They probably felt threatened that he was invading their "kingdom".
What was the purpose of keeping these chimps? Why take on the responsibility of caring for vicious, unpredictable animals? Why do some people have this facination??