The fully aquatic lifestyle of dugongs means that direct observation of social tusk use is not usually possible. This study used body scarring as an indicator of tusk function by males. Tusk rake scars on 298 live wild dugongs, of both sexes and all sizes, were categorized and counted in over 1,000 photographs, and examined in relation to maturity and reproductive activity over seasons. All dugongs had tusk scars, but adults were the main recipients. Sexually active adults acquired the greatest number of fresh tusk wounds during the mating season. Subadults received fresh rakes at similar numbers year-round. Adult males had more scars on the mid and posterior dorsum, indicating that males direct combative force to these regions of the male body when competing for females. Adult females had heaviest scarring and more tusk puncture wounds on the anterior-mid dorsum and head, suggesting that male dugongs use tusks in sexual coercion. Heavy scarring sustained by solitary calves compared to dependent ones, suggests that mothers afford some protection. Body scarring caused by tusks may serve as an indicator of reproductive contribution of the recipients, providing that successful males are involved in more reproductive competitions, and successful females in more mating events.

中文翻译：

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身体疤痕作为儒艮（Dugong dugon）象牙社会功能的指标

儒艮的完全水生生活方式意味着通常不可能直接观察社会獠牙的使用情况。这项研究使用身体疤痕作为男性长牙功能的指标。在 1,000 多张照片中对 298 只活的野生儒艮的獠牙耙疤痕进行了分类和计数，并检查了不同季节的成熟度和繁殖活动。所有儒艮都有象牙疤痕，但成年人是主要的接受者。在交配季节，性活跃的成年人获得最多的新鲜象牙伤口。Subadults 全年收到类似数量的新耙。成年雄性在背部中部和后部有更多的疤痕，表明雄性在争夺雌性时会将战斗力直接施加到雄性身体的这些区域。成年雌性在前中背部和头部有最严重的疤痕和更多的獠牙刺伤，这表明雄性儒艮在性胁迫中使用獠牙。与依赖的小牛相比，单独的小牛留下的严重疤痕表明母亲提供了一些保护。由象牙引起的身体疤痕可以作为接受者生殖贡献的指标，前提是成功的雄性参与更多的生殖竞争，成功的雌性参与更多的交配活动。