Sibling relationships can include everything from love and support–to tension, competition, and conflict. They might also play a fundamental role in the evolution of our species. In the final installment of our threepart series on family relationships, researchers Karen Kramer, Cat Hobaiter, and Rachna Reddy explore surprising new science about the role of siblings in primate and human evolution.

Credits:
This episode was produced by Leo Hornak. Sound design and production by Ray Pang. Host and executive producer, Meredith Johnson. Our editor is Audrey Quinn. Theme music by Henry Nagle, additional music by Lee Roservere and Blue Dot Sessions.

Sponsors:
Dana LaJoie and Bill Richards, Jeanne Newman, the Ann and Gordon Getty Foundation, and the Joan and Arnold Travis Education Fund.