You can structure the sentence differently, and maybe it will help. "Positioning" is wrong, but maybe it will sound more wrong if you say it differently. 1a: (original) Positioning at the top of the food chain, the Bengal tiger of southern India has no predators except man. 1b: The Bengal tiger of southern India, positioning at the top of the food chain, has no predators except man. 2a: (original) Positioned at the top of the food chain, the Bengal tiger of southern India has no predators except man. 2b: The Bengal tiger of southern India, positioned at the top of the food chain, has no predators except man.

"To position" is a transitive verb. That will give you the correct answer.