Auricular exostoses in the prehistoric population of Gran Canaria

Abstract

Auditory exostoses are bone anomalies located in the external auditory canal. The bulk of clinical observations and some experimental data support the idea that their development depends on prolonged exposure to cold water. This study was performed in order to analyze the prevalence of auditory exostoses among the prehispanic population of Gran Canaria, comparing it between men and women and between individuals buried in coastal regions and central highlands. We analyzed 323 crania, 41 of which showed auditory exostoses. Marked differences in prevalence were observed between the individuals buried in the central highlands (0.88%) and those buried in coastal regions (40.21%). Among the latter, the prevalence was similar in men (41.67%) and in women (38.89%). These data support the hypothesis that individuals buried in coastal regions performed economic activities related to exploitation of marine resources, whereas those living in the central highlands did not; however, diachronic variation cannot be excluded.

Novas perspectivas na reconstituição do modo de vida dos sambaquieiros

“…Altas freqüências dessa anomalia foram registradas em pessoas envolvidas em atividades aquáticas intensas (Kroon et al, 2002), como surfistas, mergulhadores e pessoas responsáveis pela obtenção de recursos aquáticos (Standen et al, 1997). Apesar de causas genéticas já terem sido consideradas como determinantes da exostose auditiva, atualmente considera-se que sua etiologia esteja associada a fatores ambientais, especialmente ao contato dos canais auditivos com água fria (Van Gilse, 1983;Kennedy, 1986;Deleyiannis et al, 1996;Standen et al, 1997;Chaplin & Stuart, 1998;Velasco-Vazquez et al, 2000).…”

External auditory exostoses and prehistoric aquatic resource procurement

“…In some studies no clear sexual differences are seen, at least at the statistical level of significance (e.g. Dutour and Onrubia-Pintado, 1991;Okumura et al, 2007;Velasco-Vazquez et al, 2000;Villotte et al, 2014), suggesting that both sexes were engaged in aquatic activities in these groups, while in other studies a significant difference is shown, usually with males having higher frequencies (e.g. Kennedy, 1986;Özbek, 2012;Standen et al, 1997).…”

“…Crowe et al, 2010;Cooper et al, 2010;Hurst et al, 2004;Ito and Ikeda, 1998;Özbek, 2012;Standen et al, 1997;Velasco-Vazquez et al, 2000;Villotte et al, 2014). The rate of interobserver error for qualitative methods can be quite high, however (5 to 15% according to Gregg and McGrew, 1970;Villotte et al, 2014, but see Crowe et al, 2010, likely due to lack of clear definition of the transition between grades.…”

“…Because the temperature of the waters of the tropics is relatively warm these tropical/subtropical areas are characterized by low frequencies as well (Kennedy, 1986). However, more recent studies note frequent EAE development in population samples living in areas between 0-30°north and south latitude, where cold streams lead to sea waters that are relatively cooler than expected according to latitude, or where the water is warmer but with relatively low atmospheric temperatures and strong wind chill (Okumura et al, 2007;Standen et al, 1997;Velasco-Vazquez et al, 2000).…”

“…The most common approach is to compare frequencies of EAE in groups living in different environments, usually from coastal and inland regions (e.g. Okumura et al, 2007;Standen et al, 1997;Velasco-Vazquez et al, 2000). Not surprisingly, these studies show significant differences between samples, those from coastal regions having higher frequencies.…”