The authors saw that in their model, extinction would have been possible within 10,000 years with a decrease in fertility rates of young (<20 year-old) Neanderthal women of just 2.7 percent; if the fertility rate decreased by 8 percent, extinction occurred within 4,000 years. If this decrease in fertility was amplified by a reduction in survival of infants (children less than one year old), a decrease in survival of just 0.4 percent could have led to extinction in 10,000 years.
The authors intended to explore possible Neanderthal extinction scenarios rather than to posit any definitive explanation. However, the researchers note that this study is the first to use empirical data to suggest that relatively minor demographic changes, such as a reduction in fertility or an increase in infant mortality, might have led to Neanderthal extinction. The authors note that modelling can be a useful tool in studying Neanderthals.
The authors add: “This study of the disappearance of the Neanderthals published today in PLOS ONE does not attempt to explain “why” the Neanderthals disappeared, but to identify “how” their demise may have taken place. This original approach is made on the basis of demographic modeling. The results suggest that a very small reduction in fertility may account for the disappearance of the Neanderthal population. According to this research, this decrease did not concern all female Neanderthals, but only the youngest (less than 20 years old).” Paper. (open access) – Anna Degioanni, Christophe Bonenfant, Sandrine Cabut, Silvana Condemi. Living on the edge: Was demographic weakness the cause of Neanderthal demise? PLOS ONE, 2019; 14 (5): e0216742 DOI: 10.1371/journal.pone.0216742 More.
Demographic decline is insidious because its pace appears slow in human terms (generations) but eventually, a freefall can occur. For example, young Neanderthals would eventually find themselves joining other groups because there aren’t enough other Neanderthals around. And the rest is… 23 and me.
See also: Neanderthal Man: The long-lost relative turns up again, this time with documents
A deep and abiding need for Neanderthals to be stupid. Why?
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