Costs and benefits of solitary living in mammals

• Published in: Journal of zoology (1987) 2024-05, Vol.323 (1), p.9-18
• Main Authors: Makuya, L., Schradin, C.
• Format: Article
• Language: English
• Subjects: Animal biology; Biodiversity and Ecology; Breeding; Communal breeding; Comparative analysis; Comparative studies; Ecologists; Environmental conditions; Environmental Sciences; Evolution; group living; Harsh environments; Life Sciences; mammal; Mammals; Social behavior; Social conditions; Social interactions; Social organization; social system; socio‐ecology; solitary living; thermoregulation; Vertebrate Zoology
• ISSN: 0952-8369; 1469-7998
• DOI: 10.1111/jzo.13145

While for decades behavioural ecologists have studied the costs and benefits of group living, solitary living has received little attention. Instead, it was assumed to be the default stage from which sociality evolved. Mammals underwent around 200 million years of social evolution, with a few species evolving communal or cooperative breeding in harsh environments. Other mammal species are successful with solitary living in exactly the same and many other environments, indicating that solitary living is beneficial under many environmental conditions. Comparative studies on mammals indicate that solitary living might not be the ancestral but a derived state. Solitary living in mammals is less common than previously believed, occurring in 22% of the studied species. Here, we review costs and benefits of solitary living in mammals. We found very few studies that considered solitary living and show important future avenues of research based on the factors that are important for the evolution of group living. We also emphasize that a solitary form of social organization does not imply an unsocial lifestyle: solitary mammals typically have non‐random but individualized social interactions with their neighbours, indicating important social structure. Seven main factors that influence the social organization of a species. + indicates which condition favours solitary living, − which favours group living. Combined, these factors influence whether solitary or group living leads to a net benefit for females. In mammals, social organization is mainly determined by how females distribute themselves, while males follow female social organization, being solitary living when females are solitary, joining groups when females form groups.