"The word 'apes' usually means chimpanzees, gorillas, orang utans, gibbons, and simangs. We admit that we are like apes, but we seldom realise that we are apes. Our common ancestor with the chimpanzees and gorillas is much more recent than their common ancestor with the Asian apes – the gibbons and orangutans. There is no natural category that includes chimpanzees, gorillas and orangutans but excludes humans."