limb movement

On chickens, dinosaurs and a fake tail

Chickens with fake tails simulate the shift in the center of body mass through Tetrapod evolutionary history, shedding light on limb movement of bipedal dinosaurs. 

Chickens raised with fake tails can demonstrate how T-Rex and other bipedal dinosaurs moved. Researches added a prosthetic tail to chickens in order to experimentally demonstrate that shifts in the body’s Center of Mass (CoM) caused limb movement to gradually change from hip to knee driven. Wings caused the CoM to move towards a more anterior position, leading birds to present ‘knee-driven’ movement, in which the hind limb moves by knee flexion empowered by the hamstrings. When the prosthetic tail is added to the chick right after it hatches, CoM gradually shifts with the birds’ development, leading to a more ‘hip-driven’ hind limb movement. The study is a partnership between the Universidad de Chile, the University of Illinois at Chicago and the University of Chicago, and was published at PLoSOne, Grossi et al. 2014. Walking Like Dinosaurs: Chickens with Artificial Tails Provide Clues about Non-Avian Theropod Locomotion,