Short but interesting
interview with
Carel van Schaik (orangutan researcher) in the NYT:
Q. So your discovery that the orangutans learned tool use from one another explains "the rise of human culture" part of your book's subtitle?
A. Well, yes. Orangutans split off from the African lineage some 14 million years ago. If both chimps and orangutans make tools, our common great ape ancestor probably had the capacity for culture.