Neanderthals may have been doomed to extinction because they had persistent, life-long ear infections due to the structure of their Eustachian tubes, a team of researchers from Hackensack Meridian School of Medicine at Seton Hall University, Icahn School of Medicine at Mount Sinai and SUNY Downstate College of Medicine believes.
The structure of the Eustachian tube in a Neanderthal man. Image credit: SUNY Downstate Health Sciences University.
“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,” said co-author Dr. Samuel Márquez, from SUNY Downstate College of Medicine.
“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.”
In the age of antibiotics, these infections are easy to treat and relatively benign for human babies.
Additionally, around age 5, the Eustachian tubes in human children lengthen and the angle becomes more acute, allowing the ear to drain, all but eliminating these recurring infections beyond early childhood.
But unlike modern humans, the structure of the Eustachian tubes in Neanderthals didn’t change with age — which means these ear infections and their complications, including respiratory infections, hearing loss, pneumonia, and worse, would not only become chronic, but a lifelong threat to overall health and survival.
“It’s not just the threat of dying of an infection. If you are constantly ill, you would not be as fit and effective in competing with your Homo sapiens cousins for food and other resources,” Dr. Márquez said.
“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. It adds to our gradually emerging picture of the Neanderthals as very close relatives who nonetheless differed in crucial respects from modern man,” said American Museum of National History paleoanthropologist Dr. Ian Tattersall, who was not involved in the study.
“The strength of the study lies in reconstructing the cartilaginous Eustachian tube,” added SUNY Downstate College of Medicine’s Professor Richard Rosenfeld.
“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.”
The findings appear in the journal Anatomical Record.
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Anthony Santino Pagano et al. Reconstructing the Neanderthal Eustachian Tube: New Insights on Disease Susceptibility, Fitness Cost, and Extinction. Anatomical Record, published online August 31, 2019; doi: 10.1002/ar.24248
