New study confirms spending time with friends may lengthen your life – but perhaps not for the reasons you think

Research has repeatedly made the link between social connections and longevity.

A new study published in the journal “Nature Communications” offers confirming evidence – but possibly for a surprising reason.

Researchers analyzed the lifespans and social lives of almost 1,000 mammal species. They found that species that live in groups tend to live longer than solitary animals. That isn’t particularly surprising. For years, researchers have suggested that social behavior, including spending time with friends and family, helps to prolong life for emotional reasons.  Personal connections enhance a sense of purpose.

In their preliminary analysis, these researchers seemed to confirm that. They analyzed scientific literature data on the social organization of 974 mammal species, splitting them into three categories: solitary, pair-living and group-living. When the researchers compared these three groups with data on the mammals’ known longevity, they found group-living mammals tended to live nearly twice as long as the solitary species.

The researchers then accounted for body mass since bigger mammals tend to live longer than smaller ones. They found that social animals, like bats, live longer than solitary animals, like shrews. 

“We were so surprised, because individuals who live in groups also face a lot of costs, such as competition for potential mating partners and food,” said evolutionary biologist and study co-author Xuming Zhou of the Chinese Academy of Sciences in Beijing, who was quoted in Science News.  

But the research got particularly interesting when Zhou and his colleagues looked at brain tissue samples from 94 mammal species and analyzed the transcriptome – the full range of  RNA – to understand biological differences between social and solitary mammals.

They found 31 genes whose activity relates to both longevity and social categories. Many of the genes appear to be related to the immune system, which may be helpful in fighting pathogens that sometimes spread through the social group. Other genes were associated with hormone regulation.

This additional step in the research suggests that social behavior involves far more than emotional or psychological benefits.  There may be a genetic link to longer life. 

Zhou promises to undertake further research, but his team’s initial findings are intriguing and suggest that social behavior may be a side effect to genetically programmed longevity, rather than an emotional or personality distinction.