title: Social integration confers thermal benefits in a gregarious primate.
abstract: Sociality has been shown to have adaptive value for gregarious species, with more socially integrated animals within groups experiencing higher reproductive success and longevity. The value of social integration is often suggested to derive from an improved ability to deal with social stress within a group; other potential stressors have received less attention. We investigated the relationship between environmental temperature, an important non-social stressor, and social integration in wild female vervet monkeys (Chlorocebus pygerythrus), using implanted data loggers to obtain direct measures of core body temperature. Heterothermy (as measured by 24-h amplitude of body temperature) increased, and 24-h minima of body temperature decreased, as the 24-h minimum ambient temperature decreased. As winter progressed, monkeys became increasingly heterothermic and displayed lower 24-h minima of body temperature. Monkeys with a greater number of social partners displayed a smaller 24-h amplitude (that is, were more homoeothermic) and higher 24-h minima of body temperature (that is, became less hypothermic), than did animals with fewer social partners. Our findings demonstrate that social integration has a direct influence on thermoregulatory ability: individual animals that form and maintain more social relationships within their group experience improved thermal competence compared to those with fewer social relationships. Given the likely energetic consequences of thermal benefits, our findings offer a viable physiological explanation that can help account for variations in fitness in relation to individual differences in social integration.
authors.affiliation: Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.|Department of Anthropology, University of Wisconsin-Madison, 1180 Observatory Drive, Madison, WI, 53706, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: McFarland
authors.affiliation: Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Andrea
authors.initials: A
authors.lastname: Fuller
authors.affiliation: Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Robyn S
authors.initials: RS
authors.lastname: Hetem
authors.affiliation: Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.|School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth, WA, Australia.
authors.forename: Duncan
authors.initials: D
authors.lastname: Mitchell
authors.affiliation: Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.|School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth, WA, Australia.
authors.forename: Shane K
authors.initials: SK
authors.lastname: Maloney
authors.affiliation: Department of Psychology, University of Lethbridge, Lethbridge, AB, Canada.|Applied Behavioural Ecology & Ecosystems Research Unit, University of South Africa, Pretoria, South Africa.
authors.forename: S Peter
authors.initials: SP
authors.lastname: Henzi
authors.affiliation: Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.|Department of Psychology, University of Lethbridge, Lethbridge, AB, Canada.
authors.forename: Louise
authors.initials: L
authors.lastname: Barrett
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation; D002522:Chlorocebus aethiops / Q000502:physiology*; D005260:Female; D012621:Seasons; D012919:Social Behavior; D013019:South Africa; D013696:Temperature
keywords: body temperature; cold stress; primates; sociality; thermoregulation; vervet monkeys