A new study by the European Synchrotron Radiation Facility (ESRF) suggests that early Homo species may have experience extend childhoods well before significant brain enlargement, challenging longstanding evolutionary assumptions.
This findings are based on the dental development of a nearly complete sub-adult Homo skull, unearth at the Dmanisi site in Georgia and dated to 1.77 million years ago.
The ESRF team, collaborating with the University of Zurich and the Georgian National Museum, utilise advance synchrotron imaging to study the specimen’s teeth, providing unprecedent insight into the growth patterns of early humans.
The research examine dental microstructures, which, like tree rings, record daily growth, thus offering insight into overall physical development.
Christoph Zollikofer, the study’s lead author from the University of Zurich, explains that teeth fossilise well and serve as a reliable record of childhood growth.
As per Paul Tafforeau of ESRF, who co-author the study, dental development often correlates with broader bodily growth, including brain development.
Analyses reveal a unique pattern in which back teeth mature more slowly than front teeth in the specimen’s first 5 years.
This pattern, combine with an observe reliance on adult caregivers, supports a hypothesis that early Homo juveniles may have dependent on adults for extend periods, like modern humans.
The discovery can reshape how the “big brain-long childhood” hypothesis is understood.
As before theories held that prolong childhoods evolve primarily due to increases in brain size.
Yet, this Dmanisi specimen, while having a smaller brain comparable to great apes, show evidence of prolong support by older group members, possibly indicating that communal care, rather than brain size, was the initial driver of extended development.
David Lordkipanidze of the Georgian National Museum observe that one older Dmanisi individual survived toothless, implying social structures where knowledge was pass across generations.
This evolutionary framework suggests that the extend childhood emerge first, enabling cultural transmission, which subsequently favour brain growth and delay maturation.
This findings, publish in Nature, indicate that the gradual evolution of extend childhoods may have play a foundational role in early human development and social cohesion.
