I think the bloodsport theory is pure Hoowee! Nothign supports it other than Sam being dragged to the center and lasting long enough to scream twice.
1. So, This begs the question of why do they kill if they're able to digest and are interested in "People food" *no pun intended*
2. What does this mean evolution wise?
3 How the hell can they tell what's food if it isn't running from them? Smell? Sight? Memory?
And thank you Nik and Wooly for breaking my little Soliloquy. LOL