无量山大寨子黑长臂猿一夫二妻制的群体结构及其行为学原因

2003年8月—2005年8月,对无量山大寨子5个黑长臂猿群体的结构和组成进行了观察。当一个群体在早晨鸣叫或依次通过树冠时,记录群体的结构和组成。每个群体都由1个成年雄性、2个成年雌性及其后代组成。2003年8月平均群体大小为6·2只;到2005年8月,平均群体大小发展为6·4只,其中有2个亚成年雄性从出生群迁出,且有3只幼猿出生。在3个群体(G1、G2和G3)中两个成年雌性都成功繁殖了后代。同一群体内两个成年雌性间无攻击或等级行为。2005年4月15日,当一只亚成年雌性进入G3的领域后,两只成年雌性对其进行追逐驱赶,并且干扰其与成年雄性配合进行二重唱,成年雄性没有直接驱赶流浪的亚成年雌性,10天后这只亚成年雌性离开了G3的领域。亚成年雄性经常与群体其他成员保持一定距离,并且在出生地通过独唱练习鸣叫。黑长臂猿可能通过亚成年雄性和雌性的迁出,及成年雌性对外来流浪雌性的驱赶维持这种一夫二妻的群体结构。

Polygynous Mating System and Behavioural Reason of Black Crested Gibbon (Nomascus concolor jingdongensis) at Dazhaizi, Mt. Wuliang, Yunnan, China

The field research on five black crested gibbon groups, recently performed at Da zhaizi, Mt. Wuliang, Central Yunnan, China, showed that all groups in the local population consisted of one adult male, two adult females and 2-5 sub-adults, j uveniles and infants. The mean group size was 6.2 in August 2003 and 6.4 in Augu st 2005. Two sub-adult males disappeared from their natal home range and three newborns were given birth in Group 3 (G3) and G4 during this study. The two adul t females in G1, G2 and G3 gave births and/or carried babies but at different ti mes. There was no aggressive or dominating behaviour observed between the two ad ult females. One floating female was first seen in G3's territory on April 15, 2 005. The two resident females interrupted her duet with adult male and chased he r. We did not observe adult male chased this floating female and she left G3's t erritory 10 days later. Sub-adult males often kept distance with the family, an d they often sang solo bouts in their natal territory before they dispersed. The sub-adult males and females dispersed from natal territory and two adult resid ent females rejected the third one, which might were the reasons why the black g ibbon groups were polygyny in Dazhaizi.