The cause for Neanderthals' extinction could have possibly been due to diseases carried by early modern humans migrating out of Africa, according to a new study. Since both early human species are hominin, researchers believe that it has been easier for pathogens to spread among the two populations, making Neanderthals weak, triggering a catalyst for their imminent extinction.
Scientists from the University of Cambridge and University of Oxford Brookes suggest that Neanderthals disappeared in Europe some 40,000 years ago even if they co-existed with humans for thousands of years prior to this.
Scientists also consider how diseases have been constantly evolving with our human ancestors for millions of years. Many experts also believe that infectious diseases emerged during the beginning of agriculture when living with livestock can provide more hosts to spread diseases.
In this new study, evidence from pathogen genomes in DNA reveals how some infectious diseases are most likely thousands of years older than first thought.
There is still no evidence yet showing that transmission of infectious diseases occurred between humans and Neanderthals, however there is evidence that diseases are being spread between humans and other hominin species. Past studies show how Neanderthals and humans have interbred with one another when humans first arrived in Europe, which suggests there are greater chances of spreading diseases among species encounters.
The diseases that were transmitted to Neanderthals include herpes, stomach ulcers and tapeworm infestation. These diseases can significantly weaken the immune system of Neanderthals making them less fit to search and hunt for food.
According to author of the study, Charlotte Houldcroft from University of Cambridge's Division of Biological Anthropology, humans who were migrating out of Africa are apparently a reservoir for tropical diseases. Since the Neanderthal population in Eurasia are more adapted to their geographical environment and diseases, this exposure to new pathogens from Africa are imagined to be devastating.
Theories about the exact cause why Neanderthals died off are plenty, stating that humans could have challenged Neanderthals for resources, while others suggest that their inability to adapt to climate change is linked to their demise. This new study is published in the American Journal of Physical Anthropology.