I agree with Liz - imo, humans are the most dangerous as we have the ability to build / manufacture tools and weapons that make us more powerful and destructive than any other animal species.
However, if you want some more tiger info, tigers aren't born as man-killers, nor do they kill for fun.
They will eat deer / antelope etc for all their lives as long as there are sufficient numbers of their usual prey, even if villages are within their territory.
They only eat pets / livestock / children etc if there is no other option, and only attack humans if they feel they or their cubs are in danger.
That said, once they have killed a human, they continue attacking and/or killing humans. There is a chap that is trying to rehabilitate the man-killers, rather than have them shot, because you can't prove which animal is the guilty party.