Strength in numbers: Group size enhances individual survival and colony longevity in Damaraland mole-rats Fukomys damarensis
Year: 2025
Type: article
Abstract: Cooperative behaviour presents an evolutionary paradox because although dispersal may increase direct fitness, many individuals forego reproduction to assist others. In arid-dwelling subterranean mammals, the high energetic costs of underground foraging, together with scarce and patchily distributed food resources are thought to have favoured the evolution of group living and cooperative breeding. These social systems are believed to enhance foraging efficiency and improve the survival prospects of individuals and groups. Using a longitudinal dataset from a wild population of Damaraland mole-rats ( Fukomys damarensis ) in arid central Namibia , we examine how group size predicts survival and persistence at both the individual and group levels. Our findings show that larger groups confer significant apparent survival benefits, that is the probability that an individual survives and remains available for recapture or resighting, reflecting both true survival and site fidelity, and also enhance colony persistence relative to solitary animals or pairs. We further demonstrate that these very small social-unit states are inherently unstable as without increases in group size, they are unlikely to persist within the population for extended periods. Larger groups clearly enhance survival, making remaining in the natal colony more beneficial than dispersing in an arid environment where dispersal is highly risky.
Source: Journal of Arid Environments
Institutions: University of Pretoria, University of Cape Town
Language: English
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,200
Award: G3995327189
OpenAlex ID: W4417142241