A robotic life form simulates a live creature responsive to a changing environment sensed by the robot, and has a robotic body that is articulated for motion around an upright axis and supported by at least two legs, each having at least two joints. The neck of the body terminates in a head provided with eyes and a mouth, and, in the illustrated creature, has a tail. Internal and external input sensors are located on the robotic body and responsive to touch, sound and lighting conditions, motion, food, temperature, voice commands, time of day, and obstacles and hazards, and include a head touch sensor, a plurality of touch sensors extending along a torso of the body, and a plurality of touch sensors on the feet. Actuators responsive to the input sensors control the eyes of the robot, opening and closing of its mouth, movement of the head, movement of the neck relative to the torso, and relative movements of the front and rear sections of the torso to cause the torso to pivot and twist and thereby provide lifelike responses to the sensed conditions. Drive index levels in accordance with priority criteria selected from a plurality of animation groups determine the drive index levels, and servo actuators associated with the body are responsive to dominant drive indexes causing the robot to execute animations resulting therefrom.