Shape of, and body direction in, huddles of Japanese macaques (Macaca fuscata) in Arashiyama, Japan

Abstract

We studied huddles of Japanese macaques (Macaca fuscata) in the Arashiyama E troop at the "Arashiyama Monkey Park, Iwatayama" of Kyoto, central Japan. The macaques made physical contact with other individuals and formed huddles when the air was cold. The 99-101 adult females and 26-36 adult males in the study troop formed 345 huddles during 42 scan samples in the winter of 2001 and 376 huddles during 52 scan samples in the winter of 2002. The average size of huddles was 2.3 (range 2-7) individuals. Males huddled less frequently than females. Maternal kin-related dyads formed 2-female huddles more frequently than unrelated dyads. Choice of huddling partners might restrict the size of huddles. The most frequently observed 3 and 4-member huddles were triangular and diamond-shaped. Macaques usually huddled ventro-ventrally, ventro-laterally, and ventro-dorsally. A third individual frequently placed the ventral part of its body against the first individual and simultaneously put the lateral part of its body against the second individual, so that the 3 individuals formed a triangular huddle. This behaviour indicates that Japanese macaques choose their position and body direction in the huddle to reduce the area of body surface exposed to the air, thereby conserving body heat.

Behavioral adjustments and support use of François' langur in limestone habitat in Fusui, China: Implications for behavioral thermoregulation

“…For instance, when T a is high, primates reduce their daily travel distance (McLester, Brown, Stewart, & Piel, 2019), spend more time resting in the shade ( Callithrix jacchus : Abreu, De la Fuente, Schiel, & Souto, 2016; Fuente, Souto, Sampaio, & Schiel, 2014; Colobus polykomos : Dasilva, 1992; Papio cynocephalus: Stelzner, 1988), and stay in cooler microhabitats (e.g., caves) during the day ( Pan troglodytes verus : Pruetz, 2007; A. palliate : Thompson et al, 2016). On the other hand, when T a is low, primates respond by adopting alternative behaviors: They may change social relationships (increasing physical contact with others) within their group to benefit their thermal competences (McFarland et al, 2015), adjust nest architecture to increase thermoregulation (Stewart, Piel, Azkarate, & Pruetz, 2018), preferentially use heat‐conserving postures in sunny areas or stay under direct sunlight ( Alouatta caraya: Bicca‐Marques & Calegaro‐Marques, 1998; Callicebus nigrifrons: Gestich, Caselli, & Setz, 2014; P. cynocephalus: Stelzner & Hausfater, 1986), form huddles ( Macaca fuscata: Ogawa & Wada, 2011; Ueno & Nakamichi, 2018), select warmer microhabitats during the day ( A. palliate: Thompson et al, 2016), or remain for longer in caves ( P. hamadryas ursinus: Barrett, Gaynor, Rendall, Mitchell, & Henzi, 2004). As summarized by Dunbar, Korstjens, and Lehmann (2009), primates actively avoid thermal stress (e.g., avoid being exposed to environments with T a s that are too high or too low) through various behavioral adjustments.…”

“…Callicebus nigrifrons : Gestich, Caselli, & Setz, 2014; P. cynocephalus: Stelzner & Hausfater, 1986), form huddles (Macaca fuscata: Ogawa & Wada, 2011;Ueno & Nakamichi, 2018), select warmer microhabitats during the day (A. palliate: Thompson et al, 2016), or remain for longer in caves (P. hamadryas ursinus: Barrett, Gaynor, Rendall, Mitchell, & Henzi, 2004). As summarized by Dunbar, Korstjens, and Lehmann (2009), primates actively avoid thermal stress (e.g., avoid being exposed to environments with T a s that are too high or too low) through various behavioral adjustments.…”

Intense Body Contact Increases Homosexual Pair Bond Stability in Female Japanese Macaques (Macaca fuscata)

“…Social grooming, an intimate gesture performed between two individuals, is known to facilitate the maintenance of long-term social relationships based on mutual trust and reciprocity (Jablonski, 2021 ). While social grooming and huddling are both behaviors strongly associated with close social-bonds and kinship (Majolo et al, 2010 ; Ogawa & Wada, 2011 ), we believe that the mutual and extensive body contact shared in a pair-huddle or an embrace are of a different intensity than grooming. The quality and intimacy of social grooming depends on factors such as reciprocity, techniques and targeted body parts (Borries, 1992 ).…”

Huddling is more important than rest site selection for thermoregulation in southern bamboo lemurs

“…Pelecaniformes (Evans 1984), and Sphenisciformes (Gilbert et al 2008), while mammalian orders include Artiodactyla (Hrupka et al 2000), Carnivora (Riedman 1990), Chiroptera (Willis and Brigham 2007), Dasyuromorphia (Rhind 2003), Didelphimorphia (Canals et al 1997(Canals et al , 1998, Lagomorpha (Gilbert et al 2007), Primates (Schino and Troisi 1990;Ostner 2002;Donati et al 2011;Ogawa and Wada 2011), and Rodentia (Hayes et al 1992;Hayes 2000; Kotze et al 2008). The strategy may improve an individual's (or group's) ability to survive via maintaining optimal Tb and conserving heat (i.e., metabolic energy) by reducing the total body surface area exposed to the environment (Contrera 1984;Hayes et al 1992;Canals et al 1989Canals et al , 1997Canals et al , 1998Geiser et al 2002;Séguy and Perret 2005;Gilbert et al 2010; Primates represent a behaviourally and physiologically diverse order of small-and large-bodied endotherms that are distributed throughout various climatic and geographic zones (Lehman and Fleagle 2006).…”

“…For example, in a seasonally harsh environment, black-and-white snub-nosed monkeys (Rhinopithecus bieti) select sleeping trees with large diameters at breast height (DBH) and broad crown diameters presumably to provide effective shelter from precipitation and cold exposure (Cui et al 2006). In fact, many primates are challenged with seasonally harsh environmental conditions, and have exhibited optimal body temperature maintenance via postural changes, e.g., hunched, huddling, and sun-basking positions (Stelzner and Hausfater 1986;Dasilva 1993;Moreland 1993;Hanya et al 2007;Donati et al 2011;Ogawa and Wada 2011;Terrien et al 2011;Danzy et al 2012;Kelley et al 2016). Yellow baboons (Papio cynocephalus) utilise a hunched position to reduce heat loss during cold weather (Stelzner and Hausfater 1986), while Japanese macaques (Macaca fuscata) have been observed to habitually utilise hot springs during cold weather (Zhang et al 2007).…”