In memory of our mentor: Frans de Waal (1948-2024).

The world lost a towering figure when primatologist Frans de Waal passed away on March 14, 2024. Many are aware of his multitude of contributions to the field. His ability to see what animals were actually doing changed how we viewed first primates, then other species. He shared these insights through both traditional scientific outputs, such as journal articles and scientific presentations, and less common outputs, such as 15 books and two TED talks viewed millions of times. What may be less well known is his impact as a mentor. Here, 25 of us who were Frans' graduate students, postdocs, and long-term research assistants share his personal impact on our lives.