Neanderthals were a group of hominids who lived in Europe, Western Asia, and Parts of the Middle East during the last ice age. Like the Denisovans and modern day, Homo Sapiens Neanderthals were the direct descendants of Homo Erectus.
Despite thousands of years of living and even thriving in difficult ice age Europe, the Neanderthals as a species went extinct roughly 40,000 years ago. The first remains were found in the Engis caves of Belgium, in 1829. Since that time scientists, and historians have speculated on what lead to their extinction.
Why Did The Neanderthals Go Extinct?
The Neanderthal extinction is one of the more interesting extinction events in prehistory. Most other extinctions have a direct geological or climatological event which can be tied to them. Neanderthals don’t have any such specific short-term event. Their population numbers seem to have dwindled down to extinction.
In the past, this has served as fertile soil for creative theories. One of the more prevalent is that Neanderthals simply could not compete with Homo Sapiens. As time went on decreasing resources lead to them living on the fringes until not enough survived to constitute a viable gene pool.
Another popular theory is that Neanderthals and modern humans interbred, and by virtue of numbers, Neanderthals were simply absorbed into the Homo Sapiens’ gene pool. There are also other specialists who believe a pandemic virus struck the final blow to the Neanderthal species.
These theories and many others have their proponents, no one has ever been able to pinpoint the cause of the Neanderthal extinction with 100% certainty.
It’s believed that at their peak the total Neanderthal population totaled around 70,000. This is a very small number when it comes to maintaining a gene pool. A new study takes a closer look at how something as subtle as a decrease in Neanderthal fertility rates could have been a key contributor to their final demise.
A Closer Look At The Neanderthal Extinction
The research was conducted by paleoanthropologists from Aix-Marseille University in Marseille, France. It took a meticulous approach to study the now extensive genetic analysis of the Neanderthal genome.
It is known that Neanderthals and Homo Sapiens interacted with each other for centuries, if not thousands of years. While there is evidence of violence in these relationships, there is also evidence of other instances where they got along quite well. In fact, many specialists in the field have found evidence of interbreeding between Homo Sapiens and Neanderthal. This includes potential evidence that modern humans today possess a small percentage of Neanderthal genes.
The scientists at Aix-Marseille University in Marseille specifically looked at the “How” or the mechanics of their extinction on a genetic level. This included a wide variety of factors including conflict, viral and bacterial epidemic diseases, climate change in the late ice age, as well as the reduced fertility or survival rates in males and females.
The research returned some rather surprising results. Early on they found that the extinction process took place over a very long span of time. There wasn’t a single catastrophic event that drove a decline in population numbers.
Sophisticated computer models used given data that factored in conflicts with Homo Sapiens as well as diseases. However, the results it returned showed that that had this been the case Neanderthals would have died out rapidly. Form the time of first interaction to the death of the last Neanderthal would have only taken an estimated 4,000 to 10,000 years.
These numbers are far faster than the fossil record supports. It also supports the theory that early man and Neanderthals coexisted together rather well.
The researchers also found that potential increases in juvenile and adult survival rates, as well as strong decreases in fertility rates, were not as likely given the very long span of decline seen in the Neanderthal population. What the computer models found was that the Neanderthal extinction could have been possible within 10,000 years with a minor decrease of 2.7% in the fertility rates of young Neanderthal females.
The numbers were somewhat higher for first-time mothers who were under the age of 20 years old, where the fertility rate decrease of 8% was more likely. This reflects the higher likelihood of this age segment dying in childbirth or while pregnant. Females who had given birth in the past were more likely to survive long enough to have a second, third or even more children.
What Caused The Reduction In Neanderthal Fertility Rates?
Computer models and the fossil record hint at a wide range of factors which may have contributed to the lowered fertility rates in young Neanderthal females. For this segment of their population, first-time mothers were at higher risk for medical complications.
At the same time, they may not have had access to the minimum number of calories necessary to maintain a healthy pregnancy. This may have been the result of cultural norms in Neanderthal tribal structure, dwindling resources, or climate change. Most likely it was some combination of all these factors, which made it significantly harder for first-time expectant mothers to successfully bring their baby to term.
Of these factors, the fluctuating changes in the climate of the late ice age stand to be a primary cause. At the same time, the increasing influx of Homo Sapiens into Europe and the Middle East likely increased competition for the already meager resources available in the ice age.
If we were to extrapolate those population and fertility statistics into today’s modern world, even something as seemingly minor as a 1.3% decrease in the number of births from first-time mothers, would put Homo Sapiens on a quick path to our own extinction.
Could We See A Trend Like This In Modern Humans?
Fortunately, modern man enjoys a level of modern medical technology that far surpasses anything the Neanderthals had when it came to supporting expectant mothers to carry to term. We also have access to significant high nutrient quality foods, means to support maternal and fetal health.
Source – Livescience