Sociality and cooperative breeding are associated with enhanced longevity in insects and birds, but whether this is also true for mammals is still subject to debate. African mole-rats (Bathyergidae) have recently been claimed to be the only mammalian family in which such an association may exist because cooperatively breeding bathyergids seem to be substantially longer lived than solitary bathyergids. However, although ample longevity data are available for several social bathyergids, almost nothing is known about mortality distribution and lifespan in solitary bathyergids. Here we present robust long-term data on the longevity of a solitary African mole-rat, the silvery mole-rat Heliophobius argenteocinereus. Our findings show that this species is much longer-lived than previously believed. Nonetheless, our comparative analysis suggests that sociality has indeed a positive effect on longevity in this family. We argue that the extreme longevity seen particularly in social bathyergids is probably caused by a combination of subterranean lifestyle and cooperative breeding.

• Klíčová slova
• Heliophobius argenteocinereus, ageing, longevity, mole-rats, sociality, subterranean,
• MeSH
• dlouhověkost * MeSH
• mikroftalmičtí podzemní hlodavci * MeSH
• sociální chování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The social brain hypothesis (SBH) posits that the demands imposed on individuals by living in cohesive social groups exert a selection pressure favouring the evolution of large brains and complex cognitive abilities. Using volumetry and the isotropic fractionator to determine the size of and numbers of neurons in specific brain regions, here we test this hypothesis in African mole-rats (Bathyergidae). These subterranean rodents exhibit a broad spectrum of social complexity, ranging from strictly solitary through to eusocial cooperative breeders, but feature similar ecologies and life history traits. We found no positive association between sociality and neuroanatomical correlates of information-processing capacity. Solitary species are larger, tend to have greater absolute brain size and have more neurons in the forebrain than social species. The neocortex ratio and neuronal counts correlate negatively with social group size. These results are clearly inconsistent with the SBH and show that the challenges coupled with sociality in this group of rodents do not require brain enlargement or fundamental reorganization. These findings suggest that group living or pair bonding per se does not select strongly for brain enlargement unless coupled with Machiavellian interactions affecting individual fitness.

• MeSH
• biologická evoluce * MeSH
• chování zvířat * MeSH
• mikroftalmičtí podzemní hlodavci MeSH
• mozek * růst a vývoj   fyziologie   MeSH
• sociální chování * MeSH
• velikost orgánu MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH