From Thea Boodhoo
In your interview with anthropologist Fiona Stewart on spending a night in a treetop chimp’s nest (8 October, p 31), she says: “One of the interesting questions is when, in our evolution, did we come down to the ground, and why? When did we make the transition from sleeping in trees to sleeping on the ground?”
Maybe we left the trees to get away from the other chimps and get a decent night’s rest. In all seriousness, one of the many things we and chimps have in common is intertribal warfare. It does seem possible that our descent from the trees could have its roots in a cultural disagreement.
San Francisco, California, US
