Pods of killer whales inhabit the waters of every major ocean on Earth. Each family is able to survive thanks mainly to one member, its most knowledgeable hunter: the grandmother. These matriarchs can live 80 years or more and their expertise can mean the difference between life and death for their families. Darren Croft details the lives of killer whales and the dangers facing their survival. Lesson by Darren Croft, directed by Boniato Studio.