The case for extended lifespan in cooperatively breeding mammals: a re-appraisal

Abstract

Recent comparative studies have suggested that cooperative breeding is associated with increases in maximum lifespan among mammals, replicating a pattern also seen in birds and insects. In this study, we re-examine the case for increased lifespan in mammalian cooperative breeders by analysing a large dataset of maximum longevity records. We did not find any consistent, strong evidence that cooperative breeders have longer lifespans than other mammals after having controlled for variation in body mass, mode of life and data quality. The only possible exception to this general trend is found in the African mole-rats (the Bathyergid family), where all members are relatively long-lived, but where the social, cooperatively breeding species appear to be much longer-lived than the solitary species. However, solitary mole-rat species have rarely been kept in captivity or followed longitudinally in the wild and so it seems likely that their maximum lifespan has been underestimated when compared to the highly researched social species. Although few subterranean mammals have received much attention in a captive or wild setting, current data instead supports a causal role of subterranean living on lifespan extension in mammals.

Life expectancy, family constellation and stress in giant mole-rats ( Fukomys mechowii )

“…Longevity and ageing in African mole-rats have so far been discussed as outstanding species-specific traits [8,42], as a function of breeding status [8,9], or with regard to various social systems across species [2,43]. However, even within species with a given social system (e.g.…”

“…The relationship between sociality and longevity has been the subject of intensive research across several taxa during the past decades [1,2]. Cooperative breeders are the key to an understanding of the link between social life and longevity because they are the only group for which a positive effect of sociality on prolonged lifespan (compared to related solitary species) has been convincingly shown [3].…”

The evolution of ageing in cooperative breeders

“…Comparative studies have yielded somewhat ambiguous findings on the association between lifespan and cooperative breeding – some found longer lifespans in cooperative breeders compared to solitary species 4–7 and some did not 8,9 . Our results show large variation of evolved lifespans within solitarily breeding organisms, depending on whether individuals can queue to obtain a breeding territory or not, and within cooperatively breeding organisms, depending on whether reproductive queueing is age-dependent or independent of age.…”

Editorial: Mechanisms and Pathways Contributing to the Diversity of Aging Across the Tree of Life

“…Another understudied factor in aging is sociality and accompanying kin selection, which can modify selection pressures and the magnitude and direction of trade-offs ( Bourke 2007 ). Increased sociality is associated with a longer lifespan ( see ( Arnold and Owens 1998 ; Thorley 2020 ) for examples) and eusociality, in particular, presents a fascinating window into the evolution of aging with greatly extended lifespans compared to non-social relatives, but also diversity in aging among castes ( Keller and Jemielity 2006 ; Kramer et al, 2016 ). Giraldo and others ( Giraldo et al, 2021 ) provide a mini-review examining the relationship between eusociality and brain senescence in eusocial species.…”