Abstract. This article presents experiments that integrate competitive coevolution of neural robot controllers with ‘co-evolution’ of robot morphologies and control systems. More specifically, the experiments investigate the influence of constraints on the evolved behavior of predator-prey robots, especially how task-dependent morphologies emerge as a result of competitive co-evolution. This is achieved by allowing the evolutionary process to evolve, in addition to the neural controllers, the view angle and range of the robot’s camera, and introducing dependencies between different parameters.