Mochida Koji, Nishikawa Mari
Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto 606-8502, Japan; Tropical Biosphere Research Center, University of Ryukyus, Nishihara, Okinawa 903-0213, Japan.
Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto 606-8502, Japan.
Behav Processes. 2014 Mar;103:102-4. doi: 10.1016/j.beproc.2013.10.010. Epub 2013 Nov 8.
Co-sleeping behaviour, such as sharing a sleeping site or bed, should play an important role in determining sleep structure in mammals by mitigating predation pressure and harsh abiotic conditions during sleep. Although environmental factors surrounding sleeping sites have been studied, there is very little information on the effects of the social environment within the site on sleep in animals other than humans. Here, we quantified the duration of nighttime sleep of wild primates during behavioural observations. Wild Japanese macaques (Macaca fuscata yakui) form clusters at sleeping sites, where they huddle with group members. Macaques slept for longer when huddled in sleeping clusters with natal members than in those with non-natal members. A high degree of synchronisation of wakefulness in pairs of macaques huddling in non-natal clusters suggested that their sleep was often interrupted by the wakefulness of huddling members at night. Our results suggest that familiarity and closeness to huddling partners influence sleep duration.
同睡行为，比如共享睡眠地点或床铺，在减轻睡眠期间的捕食压力和恶劣非生物条件方面，应该在决定哺乳动物的睡眠结构中发挥重要作用。尽管围绕睡眠地点的环境因素已得到研究，但关于睡眠地点内的社会环境对除人类以外的动物睡眠的影响，几乎没有相关信息。在此，我们在行为观察期间对野生灵长类动物的夜间睡眠时间进行了量化。野生日本猕猴（食蟹猕猴屋久岛亚种）在睡眠地点形成群体，它们与群体成员挤在一起。猕猴与出生群体成员挤在睡眠群体中时比与非出生群体成员挤在一起时睡眠时间更长。在非出生群体中挤在一起的猕猴对之间的高度觉醒同步表明，它们的睡眠在夜间经常被挤在一起的成员的觉醒打断。我们的结果表明，与挤在一起的伙伴的熟悉程度和亲密程度会影响睡眠时间。
