NEW YORK — Anthropologists have been searching for what led to the extinction of the Neanderthals for centuries. Why did these primitive humanoids disappear off the face of the Earth, while Homo sapiens, or humans, survived and prospered? There have been countless theories; from a plague-like epidemic to a cataclysmic natural event in their homelands, but anthropologists have largely been at a loss to explain what happened to our very close genetic cousins.
Now, a new study conducted at SUNY Downstate is suggesting an explanation that is as unexpected as it is practical: the Neanderthals’ extinction was due to chronic ear infections.
Among humans, chronic ear infections are common in children, but ultimately very treatable and usually amount to nothing more than an annoyance for children and parents alike. Neanderthals, though, seemed to be much more susceptible to ear infections even as adults.
“It may sound far-fetched, but when we, for the first time, reconstructed the Eustachian tubes of Neanderthals, we discovered that they are remarkably similar to those of human infants,” explains co-investigator and Downstate Health Sciences University Associate Professor Dr. Samuel Márquez, in a media release. “Middle ear infections are nearly ubiquitous among infants because the flat angle of an infant’s Eustachian tubes is prone to retain the otitis media bacteria that cause these infections – the same flat angle we found in Neanderthals.”
By the age of five, human children’s Eustachian tubes lengthen and develop at a more acute angle, making it much easier for the ear to drain. This greatly reduces the chance of developing a chronic ear infection past early childhood. Conversely, the structure of Neanderthals’ Eustachian tubes did not change with age at all.
“The strength of the study lies in reconstructing the cartilaginous Eustachian tube,” comments Dr. Richard Rosenfeld, a distinguished Professor and Chairman of Otolaryngology at SUNY Downstate. “This new and previously unknown understanding of middle ear function in Neanderthal is what allows us to make new inferences regarding the impact on their health and fitness.”
While an ear infection hardly sounds like enough to completely wipe out an entire population, if left unchecked ear infections can lead to respiratory infections, hearing loss, pneumonia, and many more ailments that would almost certainly be a death sentence in a primitive, wild environment. Furthermore, if a Neanderthal were to contract an infection, it would likely persist for the rest of their existence, making the condition a life-long threat to their survival.
It’s a rather small evolutionary advantage at first consideration, but it just may have given Homo sapiens a major advantage over Neanderthals.
“It’s not just the threat of dying of an infection,” says Dr. Márquez. “If you are constantly ill, you would not be as fit and effective in competing with your Homo sapien cousins for food and other resources. “In a world of survival of the fittest, it is no wonder that modern man, not Neanderthal, prevailed.”
“Here is yet another intriguing twist on the ever-evolving Neanderthal story, this time involving a part of the body that researchers had almost entirely neglected,” comments Dr. Ian Tattersall, paleoanthropologist and Curator Emeritus of the American Museum of National History. “It adds to our gradually emerging picture of the Neanderthals as very close relatives who nonetheless differed in crucial respects from modern man.”
The study is published in the scientific journal The Anatomical Record.