Abnormal bony growths in the ear canal were surprisingly common in the Neanderthals, according to a study published August 1
External auditory exostoses are dense bony growths that protrude into the auditory canal. In modern humans, this condition is usually referred to as "summer tube" and is known to be correlated with regular exposure to cold water or cool air, although there is also a potential genetic predisposition to the condition. Such exostoses have been noted in ancient people, but little research has investigated how the condition can inform our understanding of past human lifestyles.
In this study, Trinkaus and colleagues examined well-preserved ear canals in the remains of 77 ancient people, including Neanderthal and early modern humans from the middle to late Pleistocene Epochs in western Eurasia. While the early modern human specimens exhibited similar frequencies of exostoses as modern human specimens, the condition was unusually common in the Neanderthals. About half of the 23 Neanderthal remains examined showed mild to severe exostosis, at least twice the frequency seen in almost any other population studied.
The authors suggest that the most likely explanation for this pattern is that these Neanderthals spent a significant amount of time gathering resources in aquatic environments. However, the geographical distribution of exostoses seen in the Neanderthals does not show a definite correlation with the proximity to ancient water sources or to colder climates than expected. The authors suggest that several factors were probably involved in this large abundance of exostoses, probably including environmental factors as well as genetic predispositions.
Trinkaus adds: "An exceptionally high frequency of external hearing exostoses (legumes in the ear canal;" swimmer's ear ") among Neandertals, and a more modest level among high latitude earlier upper Paleolithic modern humans, indicates a higher frequency of water resource utilization among both groups of people than is suggested by the archaeological task. Villotte S (2019) External auditory exostoses among western Eurasian late middle and late pleistocene people. PLoS ONE 14 (8): e0220464. https: … /
Funding: Parts of the data collection were funded by the Université de Bordeaux, Washington University in Saint Louis and the Agence Nationale de la Recherche ( contribution number ANR-15-CE33-0004). The financiers have no role in study design, data collection and analysis, decision to publish or prepare the manuscript.
Competing interests: The authors have stated that there are no competing interests.
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