We rely on our friends for all kinds of things — companionship, laughter, and right now — support in times of crisis. But it’s only recently that scientists have started investigating how friendship works, and why it matters to our health and well-being. On this episode, we explore the anatomy of this unique bond, with stories about what happens when friendship turns romantic, the painful experience of bestie breakups, and how friendships can form between unlikely animal pairings.

Also heard on this week’s episode:

• Science journalist Lydia Denworth discusses why friendship is essential to our health and to our survival. She is the author of “Friendship: The Evolution, Biology, and Extraordinary Power of Life’s Fundamental Bond.”
• Dakota Fisher-Vance and Cara Scharf were both diagnosed with cancer in their early 20s. They talk to us about how being young adults with cancer brought them together, and why having a shared illness has made their bond stronger. They are the co-founders of Young Adult Cancer Connection.
• Do friendship apps actually work? Reporter Buffy Gorrilla takes us on a journey as she navigates different apps while looking for friendship in Australia.
• Some animals form something akin to what we think of as friendship. It’s usually animals that live in “stable, bonded social groups,” like primates or whales. But sometimes, friendships happen with animals that aren’t usually candidates for that kind of relationship. Liz Tung reports on an unlikely friendship between two bears at the Philadelphia Zoo.
• We also created a mixtape of all of our favorite songs about friends. Check it out on Spotify or press play below.