How did ancient cultures record and retain vast amounts of information about animals and plants to pass down to future generations?
Australian science writer Lynne Kelly's latest book explores the memory techniques of traditional indigenous cultures around the world.
Dr Kelly argues that non literate cultures around the world developed what she calls "Memory codes".
She says that Aboriginal "Songlines" and neolithic monuments, such as Stonehenge were part of that memory system.
What's more, Dr Kelly says we can use the techniques of our ancestors to improve our own memories.
Dr Kelly is an Honorary Associate at La Trobe University in Melbourne and the author of sixteen books.
She talks to Kathryn Ryan.