Neanderthals Grew Fast, but Sexual

¶ … Neanderthals Grew Fast, but Sexual Maturity Came

Late; National Geographic News, September 8, 2008. By Kate Ravilious. Traditional beliefs about Neanderthals held that our closest known relative died out because they were inadequately equipped to survive and intellectually inferior to modern humans. In many ways, those beliefs are central to the presumed qualitative superiority of human beings to all other forms of animal life, both in the distant past and on earth today. However, recent findings suggest that Neanderthals were much closer to human intellect as evidenced by their cooperative hunting and tool-making abilities.

Even the current understanding of the factors responsible for their ultimate demise closely parallels issues in human physiology, in particular, medical complications that still affect childbirth among modern humans.

Unlike so-called "lower" animals, Neanderthals apparently reached sexual maturity relatively late in their chronological development, even later than modern human beings. Like modern humans, brain growth among Neanderthal infants proceeded rapidly after birth, necessitated by the physical difficulties of birthing in conjunction with a more fully-formed brain and correspondingly larger cranium. The researchers determined that the anatomical differences in the facial structure of Neanderthals necessitated greater brain growth rates in the first few years after birth in order to compensate for the additional birthing difficulties posed by differences in their anatomical facial structure in relation to the geometry of the birth canal to ensure live births.

One of the main factors that contributes to the fact that human infants are born intellectually undeveloped is that more fully developed brains encased within correspondingly larger craniums would surpass the physical and geometric limitations of the birth canal. Examination of female Neanderthal pelvic bones in conjunction with skulls of Neanderthal infants illustrates that among Neanderthals, birth was a more difficult and dangerous process than in humans. It can be presumed that the rate of Neanderthal mortality of mothers during birth and infant mortality were far greater than even the relatively high rates that prevailed among modern humans prior to the development of modern medicine. In that regard, childbirth in undeveloped countries still reflects those dangers.