Bridging Behavior and Male-Infant Interactions in Macaca thibetana and M. assamensis: Insight into the Evolution of Social Behavior in the sinica Species-Group of Macaques

Hideshi Ogawa

doi:10.1007/978-3-030-27920-2_10

Abstract

I studied social behaviors of Tibetan macaques (Macaca thibetana) at Huangshan, Anhui Province, China (30°29′N, 118°11′E), from 1989 to 1993; eastern Assamese macaques (M. assamensis assamensis) at Tham Pla Temple, Chiang Rai Province, Thailand (20°19′N, 99°51′E), from 2008 to 2012; and western Assamese macaques (M. assamensis pelops) at Shivapuri-Nagarjun National Park, Kathmandu District, Nepal (27°44′N, 85°17′E), from 2014 to 2017, as well as visiting other habitats of these macaque species. These originally wild groups remain free-ranging, but have been provisioned daily and habituated to observers. By focal animal sampling, I observed adult males and females for 10 h each in both the birth and mating seasons. Males in all study sites occasionally touched the genitalia of an infant and held an infant in front of another male. However, neither males nor females of western Assamese macaques in Nepal performed bridging behavior, in which two adults simultaneously lift up an infant. On the contrary, Tibetan macaques and eastern Assamese macaques in Thailand performed bridging behavior between males, between females, and between males and females. Adult males of Tibetan macaques and eastern Assamese macaques in Thailand sometimes sucked an infant’s genitalia during bridging behavior and during dyadic male-infant interactions. In addition, only in Tibetan macaques did adult males directly suck the penis of another adult male. These results indicate that bridging behavior and sucking an infant’s genitalia by adult males evolved in the sinica species-group of the genus Macaca, particularly in the clade of Tibetan and eastern Assamese macaques, and that penis sucking between adult males was a newly evolved event in Tibetan macaques.

Highlights

Species in the genus Macaca have many common features: forming multi-male multi-female social groups with female philopatry, male dispersal, and a linear dominance hierarchy (Thierry et al 2004)
Tibetan macaques are distributed in China, and Assamese macaques are distributed in Nepal, India, Bhutan, Bangladesh, China, Myanmar, Laos, Thailand, and Vietnam (Groves 2001; Fooden 1982; Wada 2005)
Bridging behavior was recorded in Tibetan macaques at Huangshan and Mt

Summary

Introduction

Species in the genus Macaca have many common features: forming multi-male multi-female social groups with female philopatry, male dispersal, and a linear dominance hierarchy (Thierry et al 2004). There are variations in their “dominance style” and the degree of kin-biased social relationships between females (Berman and Thierry 2010; de Waal and Luttrell 1989). The variations in social relationships between females have been systematically studied (Balasubramaniam et al 2012). In addition to social relationships between females, there are many inter-species differences in social relationships between males. There have been fewer comparative studies on social interactions between males. In this paper, I focus on social interactions between adult males and infant handling by adult males in macaques

Methods

Results

Conclusion