Acclaimed primatologist Frans de Waal died last week. His studies of the great apes — chimps and bonobos — changed our understanding of our primate cousins and ourselves. De Waal showed that primates are smart and compassionate, cooperative and competitive. They have complex relationships and cultures, just like our own.

For years, Frans de Waal directed Emory University’s Living Links Center and authored many books popularizing his findings that primates and human are not all that different. Over the years, he was also a frequent guest on Marty’s previous show, Radio Times, and this week we listen back to some favorite conversations.