By method of scan sampling,the unilateral behavior of 4 individuals of Presbytis francoisi(2 males and 2 females) in eating and grooming was observed from April to May,2004.

• 2004年4月至5月,采用扫描取样法对贵阳黔灵公园笼养状态下的4只黑叶猴(雄性2只,雌性2只)取食和梳理时的单侧行为(利手行为)进行了观察记录并对数据进行了统计分析。