Swimmer’s Ear; Abnormal bony growths in the ear canal were surprisingly common in Neanderthals, according to a study published August 14, 2019 in the open-access journal PLOS ONE by Erik Trinkaus of Washington University and colleagues. External auditory exostoses (EAE) have been noted among the Neandertals and a few other Pleistocene humans; but until recently they have been discussed primary as minor pathological lesions with possible auditory consequences.
External auditory exostoses are dense bony growths that protrude into the ear canal. In modern humans, this condition is commonly called “swimmer’s ear” and is know to be correlate with habitual exposure to cold water or chilly air; though there is also a potential genetic predisposition for the condition. Such exostoses have note in ancient humans; but little research has examined how the condition might inform our understanding of past human lifestyles.
Effect to Swimmer’s Ear
External auditory exostoses are dense bony growths protruding into the external auditory canal. They are frequently observe clinically in modern humans; which in the context of aquatic sports. First document more than a century ago clinically; their distributions across human populations have consider anthropologically since the 1930s; being employe as one of suite of discrete; cranial traits for population affinity studies.
However, their distribution among later Holocene humans has show to vary latitudinally; also to correlate with habitual exposure to cold water. In this study, Trinkaus and colleagues examine well preserve ear canals in the remains of 77 ancient humans; which including Neanderthals and early modern humans from the Middle to Late Pleistocene Epoch of western Eurasia.
While the early modern human samples exhibit similar frequencies of exostoses to modern human samples; so the condition was exceptionally common in Neanderthals. Approximately half of the 23 Neanderthal remains examine; which exhibit mild to severe exostoses; at least twice the frequency see in almost any other population studied.
Ancient water sources
The authors suggest that the most likely explanation for this pattern is that these Neanderthals; which spent a significant amount of time collecting resources in aquatic settings. However, the geographic distribution of exostoses see in Neanderthals does not exhibit; so a definitive correlation with proximity to ancient water sources nor to cooler climates as would be expected. The authors propose that multiple factors were probably involve in this high abundance of exostoses; probably including environmental factors as well as genetic predispositions.
Trinkaus adds: “An exceptionally high frequency of external auditory exostoses (bony growths in the ear canal; “swimmer’s ear”) among the Neandertals, and a more modest level among high latitude earlier Upper Paleolithic modern humans, indicate a higher frequency of aquatic resource exploitation among both groups of humans than is suggest by the archeological record. In particular, it reinforces the foraging abilities and resource diversity of the Neandertals.”