Sean B. Carroll is an award-winning scientist, writer, educator, and executive producer. He is vice president for science education at the Howard Hughes Medical Institute and the Allan Wilson Professor of Molecular Biology and Genetics at the University of Wisconsin–Madison. His books include Endless Forms Most Beautiful, Brave Genius, and Remarkable Creatures, which was a finalist for the National Book Award for nonfiction. He lives in Chevy Chase, Maryland.

Biologist Sean B Carroll talks to Craig Barfoot about his latest book, The Serengeti Rules. We find out how wolves can change the physical shape of rivers and why, on the plains of the Serengeti, 150kg is the number which determines whether you will likely get eaten or not. A thoughtful and at times humorous conversation about the state of our worlds wildlife areas and the rules which determine how nature operates. How does life work? How does nature produce the right numbers of zebras and lions on the African savanna, or fish in the ocean?