The neck of a giraffe has excellent characteristics that can serve as a good alternative for designing a large robotic mechanism. For example, the neck can rapidly move when performing necking, a motion where the giraffes strike each other’s necks. Furthermore, the neck of a giraffe helps prevent impacts and adapts to the shape and hardness of the opponent’s neck during necking. In contrast, a conventional robotic mechanism is limited in its capability to achieve such powerfulness and flexibility characteristics; that is, being powerful while having robustness against impacts and kinematic and dynamic adaptability to the opponent. This study focuses on applying those excellent characteristics of a giraffe neck to develop robotic mechanisms. Specifically, roboticists and animal anatomists have combined efforts to develop a powerful and flexible long musculoskeletal robot based on the anatomy of a giraffe neck. The musculoskeletal robot prototype is actuated using thin McKibben pneumatic artificial muscles that bend easily. The results confirm the coordination between the muscles and ligaments and the shape adaptability to an external force.