Abstract: According to behavioral characteristics，oestrous cycle of Xinjiang-Mongolia beaver
(Castor fiber birulai Serebrennikov)can be didided into 4 phases:proestrus，oestrus
metaestrus and anestrus．In proedtrus，beavers appear to be active and noisy，and food-taking decrease:In oestrus，both sexes initiate vocalization of special characteristics which is named 'Oestrous vocalization'.The frequency of males' vocalization is higher than femaled'，though it is hard to distinguish．During copulation，the males appear to be more active and its food-taking decrease more significantly，while the females' food-taking increase slightly．The ’oestrous vocalization and other behavior may serve as significant symbols to identify phases of oestrous cycle．Oestrus and copulation occur normallyin Xinjiang-Monglia beaver under rearing conditions．Copulation may occur on either land or water．

Key words: Xinjiang-Monglia beavre(Caster fiber birulai), Breeding, Reproduction, Copulation behavior

摘要： 人工饲养的蒙新河狸其动情周期可划分为4个阶段：动情前期、动情期(发情交配期)、动情后期和停滞期(动情间隔期)。动情期间雌雄河狸均表现出活跃好动，浮躁不安，食量减小；发情交配期雌雄河狸均发出低沉嘶垭的叫声，雄性叫声频率比雌性略高，爬跨交配是动情期发情的高峰。动情周期各阶段的行为特征，在雌性与阴道涂片细胞学及外生殖器形态、色泽、阴道分泌物周期性变化特征相吻合，在雄性则与睾丸及阴茎形态特征相吻合。在人工饲养条件下可以正常发情交配。交配在水中和陆上均可进行。

关键词: 蒙新河狸, 人工饲养, 繁殖, 交配行为