Rosell Frank, Thomsen Liat R
Department of Environmental and Health Studies, Telemark University College, Bø i, Norway.
J Chem Ecol. 2006 Jun;32(6):1301-15. doi: 10.1007/s10886-006-9087-y. Epub 2006 May 31.
Mammalian scent marking is often associated with territorial defense. However, males and females may demonstrate different activity patterns and play different roles. Female mammals nurture the young during lactation, while males purportedly perform other tasks more frequently, such as territorial maintenance and defense. This paper investigates the contribution made by mated pairs of adult males and females to territorial scent-marking in the obligate monogamous Eurasian beavers (Castor fiber). We hypothesized that both sexes should show territorial behavior, and predicted that they deposit a higher proportion of scent marks at borders. We also hypothesized that a sexual dimorphism exists due to reproductive constraints on the females, and predicted that males should invest significantly more in scent-marking behavior than females during summer. We obtained behavioral data by radio tracking six mated pairs of Eurasian beavers during spring and summer 2000-2001 on two rivers in southeastern Norway. Our results showed that both males and females clustered their scent marks near territorial borders, but males deposited a larger number of scent marks than females and spent more time at borders. Males were also found to have a higher scent marking rate and scent marks per night than females during summer, but not during spring. Overall, scent marks per night were higher in males than females. We conclude that both males and females Eurasian beavers carry out territorial behavior by scent marking, but males carry a larger part of the territorial defense during summer when females lactate. Our results are discussed in the light of the codefense hypothesis.
哺乳动物的气味标记通常与领地防御有关。然而，雄性和雌性可能表现出不同的活动模式并发挥不同的作用。雌性哺乳动物在哺乳期哺育幼崽，而雄性据说更频繁地执行其他任务，例如领地维护和防御。本文研究了成年雄性和雌性配偶对 obligate monogamous 欧亚河狸（Castor fiber）领地气味标记的贡献。我们假设两性都应表现出领地行为，并预测它们在边界处留下的气味标记比例更高。我们还假设由于对雌性的生殖限制存在性别二态性，并预测在夏季雄性在气味标记行为上的投入应比雌性显著更多。我们通过在 2000 - 2001 年春夏期间对挪威东南部两条河流上的六对欧亚河狸配偶进行无线电跟踪获得行为数据。我们的结果表明，雄性和雌性都将它们的气味标记集中在领地边界附近，但雄性留下的气味标记数量比雌性多，并且在边界处花费的时间更多。还发现雄性在夏季而非春季每晚的气味标记率和气味标记数量比雌性高。总体而言，雄性每晚的气味标记数量比雌性多。我们得出结论，欧亚河狸的雄性和雌性都通过气味标记来进行领地行为，但在夏季雌性哺乳时，雄性承担了更大一部分的领地防御。我们根据共同防御假说对结果进行了讨论。
