研究人员在最新一期美国《当代生物学》杂志上介绍说，他们对乌干达基巴莱国家公园的一个黑猩猩群体进行了长达10年的跟踪观察。这个黑猩猩群体十分庞大，约有150个成员，而且雄性比例很高。在10年的观察期内，这个群体曾杀死或重伤了18只其他群体的黑猩猩。

研究人员曾观察到，这一群体的黑猩猩先排成一列，静静地迅速移动，仔细观察其他群体的黑猩猩，然后发动突然袭击。一系列袭击的后果是，这一群体黑猩猩的领地扩大了约22％。

黑猩猩是人类最近的近亲。人类学家很久以前就发现，黑猩猩不同种群间会发生残杀，并推测其原因可能为争夺领地。参与这项研究的密歇根大学人类学家约翰·米塔尼认为，他们的研究首次提供了有关这一假设的清晰证据。

原文出处：

Current Biology doi:10.1016/j.cub.2010.04.021

Lethal intergroup aggression leads to territorial expansion in wild chimpanzees
John C. Mitani 1, David P. Watts 2,and Sylvia J. Amsler 3

1 Department of Anthropology, University of Michigan, Ann Arbor, Michigan, USA
2 Department of Anthropology, Yale University, New Haven, Connecticut, USA
3 Department of Sociology and Anthropology, University of Arkansas at Little Rock, Little Rock, Arkansas, USA

Chimpanzees make lethal coalitionary attacks on members of other groups [1]. This behavior generates considerable attention because it resembles lethal intergroup raiding in humans [2]. Similarities are nevertheless difficult to evaluate because the function of lethal intergroup aggression by chimpanzees remains unclear. One prominent hypothesis suggests that chimpanzees attack neighbors to expand their territories and to gain access to more food [2]. Two cases apparently support this hypothesis, but neither furnishes definitive evidence. Chimpanzees in the Kasekela community at Gombe National Park took over the territory of the neighboring Kahama community after a series of lethal attacks [3]. Understanding these events is complicated because the Kahama community had recently formed by fissioning from the Kasekela group and members of both communities had been provisioned with food. In a second example from the Mahale Mountains, the M group chimpanzees acquired part of the territory of the adjacent K group after all of the adult males in the latter disappeared [4]. Although fatal attacks were suspected from observations of intergroup aggression, they were not witnessed, and as a consequence, this case also fails to furnish conclusive evidence. Here we present data collected over 10 years from an unusually large chimpanzee community at Ngogo, Kibale National Park, Uganda. During this time, we observed the Ngogo chimpanzees kill or fatally wound 18 individuals from other groups; we inferred three additional cases of lethal intergroup aggression based on circumstantial evidence (see Supplemental Information). Most victims were caught in the same region and likely belonged to the same neighboring group. A causal link between lethal intergroup aggression and territorial expansion can be made now that the Ngogo chimpanzees use the area once occupied by some of their victims.