Shimooka Yukiko, Nakagawa Naofumi
Faculty of Life and Environment Sciences, Teikyo University of Science, Yatsusawa 2525, Uenohara, Yamanashi, 409-0193, Japan.
Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto, Kyoto, 606-8502, Japan.
Primates. 2014 Apr;55(2):327-35. doi: 10.1007/s10329-014-0411-9. Epub 2014 Feb 12.
Recently, research has focused on the effects of the concurrence of multimodal signals and their efficacy and meaning. We observed an unreported behaviour, a ventro-ventral "rocking-embrace" gesture that is always accompanied by lip smacking as the facial expression and sometimes by a girney call, in wild Japanese macaques (Macaca fuscata) living in Kinkazan Island, northern Japan. This study examined the form and contexts of the occurrence of such multimodal signals in order to elucidate its functions. Eighty-eight cases of rocking embrace were recorded during 183 h of observation over 22 days. Adult females were involved in all of the cases. Of the 71 cases between adult females in which behaviours prior to the rocking embrace could be identified, 13 cases were allogrooming interruptions, 11 were aggression, and 42 were approaches, most of which occurred between non-kin grooming partners. The rocking embrace was often followed by allogrooming. This suggests that rocking embraces occur under stressful conditions and may function to reduce tensions. This conclusion is consistent with the contexts and functions of lip smacking and girneys shown in previous studies. In contrast with lip smacking and girneys, neither a rocking embrace nor a ventro-ventral embrace (without rocking) between anoestrous adult females has been previously shown in Japanese macaques. In other macaque species, however, the latter gesture is often observed as an affiliative behaviour that immediately follows conflict; it functions to reconcile or as a greeting when it occurs immediately after an approach. Rocking embraces among the Kinkazan macaques occur in contexts similar to, and have a similar function to, the ancestral gesture of ventro-ventral embracing (which is hidden in Japanese macaques) and the ancestral display of lip smacking (which is still observed in Japanese macaques). The ventro-ventral embrace as a tactile signal might have been hidden since it was made redundant by the visual signal of lip smacking in ancestral macaques.
最近，研究聚焦于多模态信号的同时出现及其功效和意义。我们在生活于日本北部金刚山岛的野生日本猕猴（Macaca fuscata）中观察到一种未被报道过的行为，即腹对腹的“摇晃拥抱”手势，该手势总是伴随着咂嘴这一面部表情，有时还伴随着咕噜叫声。本研究考察了这种多模态信号出现的形式和背景，以阐明其功能。在22天内183小时的观察中，记录到88例摇晃拥抱的情况。所有案例均涉及成年雌性。在71例成年雌性之间的案例中，能够确定摇晃拥抱之前的行为，其中13例是梳理毛发被打断，11例是攻击行为，42例是接近行为，其中大部分发生在非亲属的梳理毛发伙伴之间。摇晃拥抱之后常常接着是相互梳理毛发。这表明摇晃拥抱发生在压力情境下，可能起到缓解紧张的作用。这一结论与先前研究中显示的咂嘴和咕噜叫声的背景及功能一致。与咂嘴和咕噜叫声不同，在日本猕猴中，此前从未显示过处于发情间期的成年雌性之间有摇晃拥抱或腹对腹拥抱（不摇晃）的行为。然而，在其他猕猴物种中，后一种手势常被观察到是一种亲和行为，紧接在冲突之后出现；当它在接近之后立即出现时，起到和解或问候的作用。金刚山猕猴中的摇晃拥抱发生的背景与腹对腹拥抱（在日本猕猴中已不明显）的原始手势以及咂嘴的原始展示（在日本猕猴中仍可观察到）相似，且功能相同。作为一种触觉信号的腹对腹拥抱可能由于在原始猕猴中被咂嘴的视觉信号所替代而不再明显。
