Researchers combined DNA-based "epigenetic clock" measures with long-term behavioral data from Shark Bay to show that male bottlenose dolphins with strong, lifelong social bonds exhibit slower biological ageing than more solitary males. The study analyzed 50 skin samples from 38 dolphins and found that cooperative behaviours and mutual support may reduce stressors that accelerate cellular ageing. While the results show association rather than causation, they suggest social connection is an important health factor across social mammals.
Lifelong Bonds Slow Cellular Ageing in Male Bottlenose Dolphins, Study Finds
Like humans, dolphins with life-long friendships age slower, study finds
Male bottlenose dolphins that maintain strong, long-term friendships show signs of slower biological ageing than more solitary males, a new study reports. The research, based on DNA markers and decades of behavioral observation in Shark Bay, suggests social bonds may help protect animals at the cellular level.
Study Design and Methods
Researchers analyzed 50 skin tissue samples collected from 38 bottlenose dolphins in Shark Bay, Australia. They combined those molecular data with long-term field records of social relationships to assess how friendship strength related to biological ageing. Biological age was estimated using an "epigenetic clock"—patterns of DNA methylation known to reflect physiological ageing more closely than chronological age.
Key Findings
The team found that males with stronger, long-lasting social ties tended to have younger biological ages than their more solitary peers. The pattern appears particularly pronounced among males, whose friendships often include coordinated behaviors such as playing together, surfing waves, resting side by side and cooperative hunting.
Male bottlenose dolphins (Simon Allen)
“We knew social bonds helped animals live longer, but this is the first time we have shown that they affect the ageing process,” said Livia Gerber of Australia’s CSIRO, lead author of the study published in Nature Communications Biology.
Possible Mechanisms
Researchers suggest several non-exclusive explanations: social partners can share the work of foraging, help in mate competition, reduce individual risk from predators, and buffer chronic stress. All of these factors may lower physiological wear and tear and slow cellular ageing. The authors caution the results show an association rather than definitive causation, but the molecular evidence strengthens the link between sociality and health.
Broader Implications
Co-author Lee Rollins of the University of New South Wales noted that epigenetic tools are increasingly valuable for understanding wild-animal ecology. The findings support the idea that meaningful social relationships benefit health across social mammals — and that companionship may be an underappreciated factor in longevity.
“The health benefits of friendship are not unique to humans, but are a fundamental biological principle across social mammals,” said Dr. Gerber.
Takeaway: Strong, long-term social bonds in male bottlenose dolphins are associated with slower biological ageing, highlighting social connection as an important component of health for social animals.
