Researchers in developmental psychology have reported various findings about animate-inanimate distinctions, especially the decision criteria of human infants categorizing animate existence, such as distinguishing animals and humans from the inanimate. The purpose of our research is to develop animate or “lifelike” behavior for communication robots based on such categorizing, which would be expected to potentially make human-robot interaction more natural. Thus we proposed a design guide of developing lifelike robots from the findings and implemented lifelike behavior into a humanoid robot based on our proposed guide. Our approach is also unique because we focus on the robot's mechanism and behavior design using environmental sensors. Consequently, we use a motion capturing system, which enables us to leapfrog technological developments for the robots' sensing abilities. Two experiments were conducted to verify its effects. The results of the first experiment verified the effectiveness of our proposed design guide. The second experiment demonstrated the effectiveness of the developed robot for investigating the effect of a robot's cognitive ability for human-robot interaction.