Social associations and vocal communication in wild and captive male savannah elephants Loxodonta africana26 Apr 2018
© 2017 The Mammal Society and John Wiley & Sons Ltd Despite growing evidence that males often associate in all-male groups, there has been no review of male savannah elephant Loxodonta africana social relationships or of the use of vocal communication within these male groups. We assess the evidence for all-male group formation and for the use of vocal communication by males throughout the savannah elephant range of southern and eastern Africa, as well as in ex-situ studies of captive animals. We derived data from two quantitative reviews of the published literature, for associations and for vocalisations, respectively. We supplemented these structured reviews with searches for books and of bibliographies. We compiled evidence from 30 studies on associative groups, and found that group size was the most commonly reported variable (mean group size reported 2–4.9; range reported 2–40 when excluding studies that included lone males). We found 22 studies reporting evidence of vocal communication in males. A total of four studies were retrieved from both searches, indicating that these areas of research may overlap. We found that male elephants are frequently reported to be in groups, throughout their range and over time, although the groups are small: median group size was three. The diversity of male savannah elephant group sizes may indicate the behavioural flexibility of the species. It could also represent a lack of studies focusing on males. We found a paucity of research on male vocal communication (5% of studies were concentrated solely on male bioacoustics), particularly in natural settings, and few studies reported the social context or role of male vocal signals outside of musth. We see great scope for future research at the important intersection between male elephant associations and vocal communication, including research on the role of vocalisations in mediating all-male associations.