雄性动物为争夺配偶权而与同性产生竞争，甚至所处环境中有潜在竞争者气味时，也会明显增加繁殖投入；而圈养条件下，难以提供这种正常的社群环境。大熊猫在圈养环境下的自然交配率较低，主要问题是雄性缺乏对雌性的兴趣，即繁殖积极性(sexual motivation)。野生大熊猫在繁殖期是存在激烈雄性竞争的，而圈养环境中竞争对手的缺失很可能是造成非正常繁殖情况的原因之一。另一方面，这种社群信息的缺失，也可能导致人工饲养条件下的动物行为结构异常。气味丰容已被广泛应用于改善圈养动物的饲养条件，可提高动物活跃性，减少刻板行为。本文旨在研究同性气味，即雄性竞争，对圈养雄性大熊猫繁殖积极性以及行为结构的影响。通过在实验公兽（n=11）圈舍内加入其它雄性的尿液、肛周腺分泌物和粪便，观察其行为反应，得到以下结果：同性气味可显著增加雄性大熊猫对环境的嗅闻探究，以及对发情雌性的观察、追随、嗅闻行为，气味提供者的数量（一/三）对结果影响不明显；气味标记、咩叫、蹬地等与领域、通讯相关的行为无变化；实验对象应对不同程度雄性竞争时的行为反应模式有所不同，接受气味刺激后12分钟，活动重点由探究环境转为关注雌性；加入同性气味后，圈养雄性大熊猫的刻板行为、活动量未发生显著变化，但行为多样性有明显提高。本研究结果为雄性竞争理论补充了新的依据，对改善圈养大熊猫行为结构、提高雄性性兴趣有一定启示，并可推广应用于异地保护和人工繁育项目。

Empirical studies have shown that males can alter their mating behavior to cope with the presence of their competitors. Exposure to odors from rivals can greatly increase male reproductive investment in a variety of animals including insects, fish, birds and rodents. Poor sexual performance in some male captive mammals is thought to be the main cause of breeding failure. However, the fact of male-male competition loss and its effects on male’s sexual motivation and reproductive investment have not been completely understood. Here we tested the influence of chemosensory cues from same-sex conspecifics on sexual motivation and behavioral structure in captive male pandas (n=11) via odors-exposure trials. We found that exposure to potential rivals’ odors increased males’ chemosensory investigation behavior, as well as their active sexual behavior towards neighboring estrous females, though changed regardless of the number of rivals (one/three). No differences between groups were found in the frequencies of scent-marking, bleating or foot scraping. Exposure trials led to changes in temporal patterns of behaviors, chemosensory investigation switched to female-oriented behavior after around 12 minutes of exposure to odor sources.Stereotypic behaviors and active status didn’t change statistically while the behavioral diversity of captive males increased significantly.We anticipate that our research will provide a fresh insight into the mechanisms underlying poor sexual performance in male captive mammals, and valuable information for the practical management and ex situ conservation of endangered species.