Ancestors' squishy skulls led to bulging brains

A new analysis of an old human ancestor fossil indicates that human brains started growing 2.5 million years ago, about the time humans started walking upright.

An unfused seam on the fossil's head indicates the skull was still pliable for several years after birth, giving the brain time to grow. An imprint of the brain on the inside of the skull also gave researchers a good view of the developing human brain.

"These findings are significant because they provide a highly plausible explanation as to why the hominin brain might grow larger and more complex," study researcher Dean Falk of Florida State University said in a statement. When humans started walking upright, it put pressure on infant skulls to stay flexible, allowing them to continue to grow for several years, the researchers suggest.

Small bones

Belonging to a 3- to 4-year-old Australopithecus africanus, nicknamed "Taung Child," the fossil skull was discovered in 1924 and dates back to about 2.5 million years ago. The specimen was initially discovered in a lime mine in South Africa, and was the first specimen of this species of hominin.
...
MSNBC.com

El bipedismo contribuyó al desarrollo del cerebro

Al nacer, la cabeza del bebé humano se adapta para pasar a través del canal del parto gracias a que sus huesos craneales no han terminado de formarse. Un equipo internacional de investigadores, que ha escaneado el cráneo fósil del niño de Taung, un Australopithecus africanus, revela que esto ya ocurría hace unos tres millones de años, cuando los homínidos empezaron a andar erguidos... [Leer más]

Referencia bibliográfica:
Dean Falk, Christoph P. E. Zollikofer, Naoki Morimoto, Marcia S. Ponce de León. “The metopic suture of Taung (Australopithecus africanus) and its implications for hominin brain evolution” PNAS, mayo de 2012.