Assessment of African elephant (Loxodonta africana) molars and mandibles and their association with estimated age and sex

Fiona Stansfield

Abstract


Introduction: Estimates of an elephant’s age are made by observing the movement of their molars through the mandible. Established ageing techniques have produced varying results and problems have been exacerbated by the difficulty of molar identification. Molar identification is made easier when the sex of the individual is known, as male teeth tend to be larger than female teeth. Elephant mandibles (n = 323) and molars of Zimbabwean origin where gender was known were studied in an attempt to identify relationships between molar/mandible size and sex. Measurements of molars and mandibles were recorded.
Results: From the molar measurements made, the crown-base length of complete molars proved to be useful in determining molar type and may be suggestive of sex in some molar types. On each mandible body, a novel marker, the age reference point, was determined and a measurement based on this point was found to be significantly associated with sex (p ≤0.05) at given ages. Furthermore, inter-rami width was found to be associated with sex between 0–5 y and highly significantly so after 12 y of age. This study also addressed the question of the impact of the number of lamellae present in a given molar type on molar occlusal life; the results suggest that the variable number of lamellae counted in this Zimbabwean population did not affect occlusal life and therefore should not influence ageing techniques.
Conclusion: This is the first detailed study in published literature of both male and female complete elephant molars of the left and right mandible from within the same populations. The results of molar size described here, together with mandible width, should aid in molar identification and sexing of found mandibles, and should therefore improve the estimation of elephant age using existing ageing techniques.




Keywords


African elephant, Loxodonta africana, molar, tooth, mandible, ageing

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