Foraging theory, the confluence of the ecology and evolution, strives to understand ecological patterns and processes. I use concepts of foraging theory in combination with mud-and-boots field biology to report the distribution and abundance of the endangered snow leopard and the Himalayan tahr on Mt. Everest of Nepal. I use the vigilance behavior of tahr to infer the status of their predator, the snow leopard, and confirm that snow leopards have returned to Mt. Everest following their disappearance some 40 years ago. I model how animals should select their habitats under predation-risk and partition time between competing fitness enhancing activities. In the former, I examine the consequence of animal’s habitat selection under the threat of predation as an additional factor. In the later, I develop a game theory model, and suggest that group size effect on vigilance behavior is contingent upon the strength of interacting effects of many eyes, dilution and predator attraction effects. In examining ecological theories, I track how top predators may structure biological communities. Furthermore, I examine a few major ecological paradigms in light of biodiversity conservation.