Huguet Hoedric, Seltmann Martin W, Htut Win, Briga Michael, Lynsdale Carly, Lummaa Virpi
Department of Biology, University of Turku, Turku, Finland.
Myanma Timber Enterprise, Yangoon, Myanmar.
R Soc Open Sci. 2025 Aug 27;12(8):250490. doi: 10.1098/rsos.250490. eCollection 2025 Aug.
Male Asian elephants exhibit phenotypic diversity in tusk development, with long, short and tuskless bulls varying in frequency among different populations. Although the factors that maintain tusk variation in Asian elephants remain unclear, tusks are considered a secondary sexual characteristic probably influenced by sexual selection. In this study, we examined the relationship between tusk diversity, faecal testosterone metabolite (FTM) and personality in male Asian elephants aged 5-60 years living in semi-captive conditions within their native habitat in Myanmar. Males with different tusk types did not display differences in FTM levels or in scores for the three main personality factors, but there were some distinctions in the trait loadings within each factor: attentiveness, activity and dominance loaded more strongly for long-tusk males, while traits like obedience, slowness and aggression showed stronger associations in short-tusk males. Our study suggests that the differences between long- and short-tusk males in testosterone levels and personality traits were, respectively, negligible and nuanced, emphasizing the complexity of tusk expression and evolution in Asian elephants.
雄性亚洲象在象牙发育方面表现出表型多样性，长象牙、短象牙和无象牙的雄象在不同种群中的出现频率各不相同。尽管亚洲象维持象牙变异的因素尚不清楚，但象牙被认为是一种可能受性选择影响的第二性征。在本研究中，我们调查了缅甸原生栖息地半圈养条件下5至60岁雄性亚洲象的象牙多样性、粪便睾酮代谢物（FTM）与个性之间的关系。不同象牙类型的雄性在FTM水平或三个主要个性因素得分上没有差异，但每个因素内的特质负荷存在一些差异：长象牙雄性在注意力、活动力和支配力方面的负荷更强，而服从性、迟缓性和攻击性等特质在短象牙雄性中表现出更强的关联。我们的研究表明，长象牙和短象牙雄性在睾酮水平和个性特征上的差异分别微不足道和细微，这凸显了亚洲象象牙表现和进化的复杂性。
