Rhinology & Otology

Biography

Biography: Peter Rhys-Evans

Abstract

For well over a century, otolaryngologists have been aware of a curious otological condition, now known colloquially as ‘Surfer’s Ear’, in which bony growths appear in the deep part of the external ear canal. The unusual aspect of these bony protrusions lies in the fact that they are only seen in surfers or rather are associated with frequent swimming and water immersion of the auditory canal.
Much has been written about the possible pathogenesis of these bony tumours, called exostoses, but several aspects still remain unclear. The fact that the condition is always bilateral is fairly obvious since both ears are immersed in water, but Why do they only grow in swimmers?; Why do exostoses only grow in the deep bony meatus and not elsewhere in the ear canal?; Why do they always grow at 2 or 3 constant sites; and, from an evolutionary point of view; What is or was the purpose and function of these rather incongruous protrusions. In recent decades, paleo-anthropological evidence has modified our ideas about early hominid evolution, inspired by Sir Alister Hardy's visionary article (1960) and Elaine Morgan's Aquatic Ape Theory (1982, 1990). At a time several million years ago following the late Miocene drought when quadruped pre-hominid apes desperately sought new sources of food, the traditionally held “Savannah Theory” (Dart, 1924) suggests that pre-hominid ape man developed a new habitat on the savannah where he stood upright “to see further” and started running after gizelle and other game. Critics suggest that if it was so advantageous for one branch of the family, why didn’t all apes evolve in this way and why does man have so many different anatomical and physiological characteristics which are unique amongst terrestrial mammals, but commonplace among aquatic and semi-aquatic mammals. A much more plausible scenario suggested by Hardy was that early pre-hominid man began to explore the rich quantity of marine food that was readily available around the shores, estuaries and rivers in that area of East Africa.
In the context of this suggested littoral influence during evolution, the senior author explored various enigmatic anatomical features relating to the upper aero-digestive tract, unique in man, that were not seen in other higher primates nor other terrestrial mammals and suggested that these were much more logically explained by an historical period of aquatic adaptation during early hominid evolution (Rhys Evans, 1992).
One of these anatomical features was the question of exostoses, which the author suggested were evolved for the purpose of protection of the delicate tympanic membrane during swimming and diving, to narrow the ear canal in a similar fashion to protective mechanisms seen in other semi-aquatic species. He suggested that if exostoses were identified in early hominid fossil skulls, this would provide good evidence to support the aquatic theory that suggests that early hominid man spent significant periods of time submerged in the water. In contrast to modern man, early hominids would not have been surfing or swimming for social reasons, but their frequent immersion in water would have been in search of food, hunting for their survival. We believe that recent fossil evidence of exostoses of the external ear canal in early hominid skulls has now established confirmation of this aquatic theory. This paper reviews the current literature regarding external auditory canal exostoses with reference to contemporary and ancient populations. We also describe the developmental embryology of the external auditory canal and suggest a hypothesis to explain the specific growth sites of the exostoses which correspond to the 3 epiphyseal growth plates of the external ear canal. We suggest that external auditory canal exostoses provide the only hard (fossil) evidence of man’s aquatic past.. We also explore other unique characteristics of the human upper aero-digestive tract that support this aquatic evolutionary theory.