Neanderthal man ' status as advanced humans ' skinny extinct relatives make the causes of their extinction a thing of considerable stake . A new model suggests that while the ultimate drive may remain unknown , a small reduction in fertility , maintain over a long enough fourth dimension , would have been sufficient , without any sudden cataclysm .
Neanderthals were never rottenly numerous , as well as being wearisome stock breeder . Dr Anna Degioanniof Aix Marseille Universite wonder if just a modest reduction in births could have pushed them over the edge . She created a theoretical account for the effects of mild change in birth pace and found an 8 percent fall in fertility would have been sufficient to bring them below 5,000 individuals in 4,000 years . Even a 2.7 percentage nightfall would have done the same over 10,000 eld . Based on her assumptions about life anticipation andage of maternity , Degioanni reason out a lowly decline in fertility for swinish women age 18 - 20 could make all the difference , even with stable birthrates at other ages .
Some biologists consider fall below 5,000 individual the spot at which extinction is inevitable , as a species miss the genetic diversity to avoid inbreeding . This view is controversial in the light of someapparent exceptions , but may be particularly applicable towidely dispersed specieswhere great distances impede interbreeding .
Even belittled alteration in richness could have make Neanderthals ' death if combined with slightly mellow rates of infant and child mortality .
Degionni ’s model , release inPLOS ONEincorporates such element as the migration of young loutish adult between population , which perchance hold up the last custody - outs in southern Europe after quenching had hap elsewhere .
" This cogitation … does not assay to explain " why " the Neanderthals disappeared , but to name " how " their demise may have take place , ” Degionni and co - authors enounce in astatement .
A declivity in prolificacy could have been the upshot of reduced food for thought provision , because of the competitionwith freshly arrivedHomo Sapiensin district Neanderthals had previously had to themselves . Alternatively , it is possible warfare between the two groups , or diseases unwittingly transmitted by the new arrivals , had the same effect .
Whatever the cause , Neanderthals were vulnerable because , even at their peak , they are thought to have count only around 70,000 across Europe and much of Asia .
fall fertility charge per unit today sometimes inducepanicked fearsof extinction for sub - populations , if not the whole of human race . However , the Neanderthal equivalence is instructive . Their entire population was less than a small urban center today , and yet it still probably took thousands of years for them to die out . Even if human fertility rates , which have been fall for five decade , overleap below replacement storey , even comparatively little ethnic population are in no imminent peril .
