In Search of Prey is an adventure that carries the reader through the heart of the Amazon. (Cardio pulmonary fiction?)
Your hook starts here
Sean Watts' life is just the way he wants it: minimal responsibilities and a job that appeases his wanderlust. He's a tour guide on the Rio Negro and hardly a novice jungle adventurer. When he's asked by Adelia Harkness, director of the Harkness Institute, to lead an expedition in search of a group of missing scientists, he doesn't think beyond the extra cash.
A World Health Organization physician, an American telecommunications specialist, and an indigenous tribesman are just a few members of his team. At first, there's no reason to consider the varied background of this unusual search party, but when they become hunted, it's obvious they were brought together for a purpose. One by one, they are being picked off, either to disappear into the darkness or to have their butchered remains left to taunt the survivors.
(I think the Governor of California will be interested in this idea)
Finally, Sean is forced to confront the fact that Adelia has an agenda in this mission, and it goes beyond finding missing scientists. She has a plan to change the future of the rainforest and, thus, the world.
While Sean and the others race to escape the danger of the jungle, forces are at work inside the institute that threaten to topple man's long-held position at the top of the food chain.
I know there are only six plots in the world but it's your job as a writer to bring something fresh and new to the page even if you're using a plot I recognize. And I'm not sure why you think people are at the top of the food chain. Lions think they are. Elephants too I bet.