After thousands of years, the reason for the Neanderthal’s extinction has finally come to light. Using isotopic analysis, it was found that both ancient humans and the Neanderthals were in direct competition for their main food source – woolly mammoths.
The first anatomically modern humans are thought to have colonised Europe around 43,000 years ago, forcing the Neanderthals into extinction approximately 3,000 years later. So, why did Homo sapiens succeed where the Neanderthals could not? There are many hypotheses, but by far the most common is that the diet of anatomically modern humans was more varied and flexible, allowing them to consume fish. However, a new study by the Senckenberg Research Institute and the Natural History Museum has blown this out of the water.
The hypothesis that early humans had a more varied diet has been fuelled by the observation that they had a higher abundance of 15N in their bone collagen when compared with Neanderthals. This difference was chalked up to the addition of freshwater fish to the diet, a conclusion that has been refuted by Prof. Dr. Hervé Bocherens and his colleagues at the University of Tübingen.
There are two main explanations for the presence of 15N in ancient human remains – a high concentration of 15N in the natural environment, especially concentrated in the meat of large herbivores whose meat makes up the majority of the diet, or a significant dietary contribution from a single prey with higher 15N abundance than prey usually found at archaeological sites (e.g. fish or mammoth meat).
Until recently, it has not been possible to distinguish between the dietary impact of freshwater fish and mammoth as both are known to have high 15N abundance and comparable levels of the 13C isotope. Due to the overlapping isotope abundances, accurate estimation from collagen alone was not possible. However, due to recent advances in stable nitrogen isotope analysis on individual amino acids, it is possible to identify the exact origin of the proteins consumed by the ancient humans.
In the study, the remains of three anatomically modern humans were examined. Found in the Belogorsk region of south Crimea, the remains were examined for phenylalanine (as a baseline) and glutamic acid (as an indicator of trophic position). Alongside the humans, the fossils of variety of prey animals found during the excavation were also investigated. Using the percentage ratio of the 13C to 15N isotopes present in the proteins of both the ancient humans and their prey, the scientists could establish the main components of their diet. Using this data, it was found that mammoth meat made up around 40-50% of the Homo sapiens’ diet. Isotopic studies of western European Neanderthals have also pointed to a significant consumption of mammoth meat, placing them in direct competition with the ancient humans.
This fierce interspecies competition for resources placed the Neanderthals under extreme stress. Without unrivalled access to their main food source – woolly mammoths – they were unable to forage enough food to survive. Whether due to superior hunting ability, increased brain size or other factors, Homo sapiens emerged on top. Without competition, humans thrived and have persisted until today. However, this is not the case for the poor woolly mammoths.
Image Credit: [http://www.nhm.ac.uk/content/dam/nhmwww/our-science/news/2014/mammoth-model-753.jpg]