Human skull evolved along with two-legged walking, study confirms -- ScienceDaily
To make their case, Russo and Kirk compared the position and orientation of the foramen magnum in 77 mammal species including marsupials, rodents and primates. Their findings indicate that bipedal mammals such as humans, kangaroos, springhares and jerboas have a more forward-positioned foramen magnum than their quadrupedal close relatives.
"We've now shown that the foramen magnum is forward-shifted across multiple bipedal mammalian clades using multiple metrics from the skull, which I think is convincing evidence that we're capturing a real phenomenon," Russo said.
Additionally, the study identifies specific measurements that can be applied to future research to map out the evolution of bipedalism. "Other researchers should feel confident in making use of our data to interpret the human fossil record," Russo said.