In this paper, the fundamental concepts of the dinosaur-like robot called TITRUS and the mechanism design of the miniature prototype robot TITRUS-III are mentioned. TITRUS is based on the concept to realize a practical mobile working platform. Its advantages are described on the discussion with two models: the rigid body system and particle system. The features of TITRUS are: 1) realizing high dynamic stability by using the neck and tail as an active dumper when the robot walks; 2) standing with the tail to compose a stable supporting triangle so that the robot can work stably; and 3) enabling it to do various tasks by applying a manipulator to the neck. Finally, the fundamental walking experiments to examine usability of the neck and tail on TITRUS-III are reported.