SLOW, solitary fruit chompers – that is how most people tended to picture the orang-utan.
Then in the early 1990s Carel van Schaik, professor of anthropology at the University of Zurich in Switzerland, discovered a bunch of very different orang-utangs in northern Sumatra.
These orang-utans use tools and are highly social. Van Schaik ascribes the animals’ traits and their dense population to a greater abundance and lower diversity of foods in the riverine backswamps they inhabit, now at risk after the tsunami.
Among Orangutans: Red apes and the rise of human culture tells the story of van Schaik’s discoveries, and…
