Tuskedness in African elephants – an anatomical investigation of laterality.

Abstract: Evidence for brain and behavioral laterality is ubiquitous across the animal kingdom, ranging from invertebrates to humans. The elephant (<italic>Elephas maximus</italic>,<italic> Loxodonta africana</italic> and <italic>Loxodonta cyclotis</italic>) serves as an interesting model for the study of lateralization given its unique morphology and behavioral repertoire in foraging, and previous reports have documented side preferences in the use of the trunk among Asian elephants (<italic>E. maximus</italic>). Some authors have even discussed the potential laterality of tusk use among elephants; yet, there are no empirical studies of actual tusk use or appropriate tusk measurements. Here, we undertake an anatomical investigation of laterality in the tusk weights from 683 African elephants (<italic>L. africana</italic> and <italic>L. cyclotis</italic>). The vast majority of individuals (94.29%) showed asymmetries in tusk weight, with the left tusk being significantly heavier than the right on average (30.65 vs. 30.24 kg; <italic>P </italic><<italic> </italic>0.05). Although the age of the individuals in our sample was unknown, the tusks of African elephants continue to grow throughout life and thus individuals with larger tusks should experience greater opportunities for disproportionate wear. Consistent with the view that the reported asymmetries result from behavioral lateralization, that is, side preferences in tusk use in rooting, stripping bark and during agonist interactions, we show that individuals with larger overall tusk pairs had a higher degree of tusk laterality (<italic>P </italic><<italic> </italic>0.001). The restricted nature of the dataset limited a number of questions that could be examined, but follow‐up research in this area could study differential tusk use in the wild and how this relates to trunk side preferences. [ABSTRACT FROM AUTHOR]