The bacteria in our guts plays a role in a whole host of things, influencing everything from weight to mood. Now, researchers have found that the rather irresistible red-bellied lemurs of Madagascar may share their gut bacteria by huddling together, a finding that could have implications for human health.
Your gut microbiome is a collection of tiny organisms, like bacteria, fungi, and viruses, that make your intestines their home. Collectively, they can weigh up to 2 kilograms (4.4 pounds), making them heavier than your brain. Although that sounds pretty disgusting, the microorganisms in your gut are generally good – they neutralize toxic by-products of digestion, discourage “bad” bacteria, and even tune your immune system.
Publishing their findings in the Journal of Animal Ecology, a team led by the University of Oxford set out to investigate what causes microbiome diversity in lemurs. Red-bellied lemurs are social, friendly creatures. They live in tight-knit groups of two to eight animals, and spend a lot of their time interacting.
The researchers found that lemurs in the same group had similar gut microbiomes. Within those communities, the closer two lemurs were, the more similar their bacteria. The scientists believe this has something to do with group immunity, whereby the syncing up of gut flora makes the group less susceptible to certain harmful infections.
“In close social groups like red-bellied lemurs, social environment is key to immunity,” said lead author Aura Raulo in a statement. “Animals that touch each other more tend to spread microbes, both good and bad, but eventually frequent social contact leads to a synchronized microbiome. Because microbes tune immune defense, this can be seen as a form of cooperative immunity: Sharing microbial allies and enemies makes infections by opportunist pathogens less likely.”
However, the team can’t yet be certain whether sharing bacteria is a good or bad thing for lemurs, as they haven’t looked into the specific types of bacteria – many of which are new to science. In the future, they hope to investigate how sharing gut flora might influence the spread of autoimmune diseases, in addition to looking at how the stress hormone cortisol might affect the gut microbiome.
“Social contact, stress physiology and gut microbiome are all intensely related,” said Raulo. “Your social contact defines how much stress you interact with, and both can influence the cocktail of microbes in your gut.”
And this isn’t just in lemurs; our own gut flora is affected by the people we live with and interact with closely. So, your friends might be influencing you a little more than you think.