It was an herbivore that walked both as a biped and as a quadruped. It was probably quadrupedal, but may have been a facultative biped. Chaotic dynamics have been exhibited by passive walking biped robots. Ramri is a biped descended from feathered, bird-like creatures. Some notable biped robots are ASIMO, HUBO, MABEL and QRIO. A biped, it moved on powerful hind legs, while its arms were reduced in size. The question of walking biped robots stabilization on the surface is of great importance. By using its tail for balance, it often walks upright as a biped. The knucker or the Tatzelwurm is a wingless biped, and often identified as a lindworm. As a facultative biped, "Anchisaurus" had to have multi-purpose front legs. A biped has the ability to breathe while running, without strong coupling to stride cycle. "H. naledi" was a biped and stood upright. The agogwe is a purported small human-like biped reported in East Africa. Ardi's divergent big toes are not characteristic of a biped. "Dracoraptor" was a biped, much like its relatives.