Our gut microbiome plays a major role in our health, and luckily, we’re not short on advice for how to take care of it. Most recommendations focus on diet, like prioritizing fiber and probiotic-rich foods, along with lifestyle tweaks such as getting enough sleep and managing stress.

But we might need to add one more factor to the list: the people we spend time with. It turns out that those closest to us can influence our internal microbial world in subtle but meaningful ways. A new study from the University of East Anglia (UEA) explores this idea by analyzing the gut bacteria of Seychelles warblers, a small songbird living on an isolated island, the perfect natural laboratory.