Predation is implicated as a major selective force in the evolution of morphological and behavioral traits of preys. In this study, I discovered unique response behaviors of two bradybaenid land snails, Ainohelix editha and Ezohelix gainesi. A. edihta restracted its soft body into its shell very quickly. In contrast, E. gainesi become even more active than before being given external stimulus, and act unique aggressive behavior. These behaviors are likely effective to avoid predation. Furthermore, each extreme behavior may be associated with differences in shell morphology between these species, so it is likely that these snails have two comparative strategies as anti-predator predation. A. edihta and E. gainesi are known by are genetically closely related each other, despite these snails have much different morphological characters. Morii et al (2015) showed that it is likely these species have evolved rapidly due to natural selection except for habitat condition, because these snails often coexist at same place. This study suggests that two land snails were evolved by predation pressure, thus suggesting co-evolution among preys and predators.