Following Hamilton (1971), this article attempts to study gregarious behavior of a potential prey on the basis of the selfish drive of each individual in the prey population to minimize its own probability of predation rather than to contribute to the welfare of the entire population. Unlike Hamilton, we concentrate on the asymmetric situation, where active pursuit and evasion endow faster individuals of the prey population with better chances to escape predation. In such situations it is shown that a certain identity of interests between the predator and some of its potential prey can evolve. Conditions for formation of an evasive herd can be analyzed as a nonzero-sum prey-predator game. Under a wide variety of conditions it can be shown that the optimum behavior for a fast prey is always such as to maximize the predation probability of the slowest prey. Finally, some other biological phenomena, typical to either evasive prey or its predators, are also suggested as following from the nonzero-sum model.