Predation on experimental groups of desert rodents by the owl, Athene brahma, was differentially successful. Owls sought to capture all types, but adult Meriones libycus were never caught, whereas juvenile M. libyens were always seized. The data support the hypothesis that hearing plays a significant role in the avoidance of owls, but direct experiments comparing owl success in capturing adults with normal and surgically impaired hearing are needed to confirm the hypothesis. Mechanisms that may influence the evolution of behavioral patterns and anatomical structures of desert rodents for evading owls are suggested.