Not being able to manage the balance needed for bipedal walking, they perfected in its place their initial bear-crawl into an adult quadruped gait.
Both types were capable of bipedal walking.
It is important to stress that both lizard-hipped and bird-hipped dinosaurs were capable of bipedal walking.
Much research has been geared towards the mechanics of how bipedal walking has evolved in the genus Homo.
The locomotion of Pachycephalosaurus might have included bipedal walking, but this goes beyond the available evidence.
How adapted it was for bipedal walking is not known, but its fingers and arms also seems to show adaptations for climbing and swinging.
Arm swing in human bipedal walking is a natural motion that each arm swings with the motion of the opposing leg.
His hind legs hadn't been designed for bipedal walking; the knees were the wrong way round and the hooves were overlarge.
In infants, where this is a rare but a normal stage prior and sometimes following bipedal walking, such a gait is called "bear crawl".
Then there was a new sound - the unmistakable sound of someone walking, of bipedal human walking.