In the last of Matthew Sweet's visits to ZSL London Zoo we consider our relations with our closest animal relatives - apes. Daniel Simmonds, Keeper at ZSL London Zoo's Gorilla Kingdom, discusses the problems that come with looking after creatures so similar to, but different from us. Is any kind of mutual understanding possible at all? Matthew picks up the theme with anatomist and anthropologist Alice Roberts, physician and philosopher Raymond Tallis and novelist James Lever. So what happens when you stare into the eyes of an ape?