John Gray considers why the human animal needs contact with something other than itself.

He tells the story of an eminent philosopher who once told him that he'd persuaded his cat to become a vegan! An effort, it seems, to get the cat to share his values. But Gray argues that there's no evolutionary hierarchy with humans at the top.

"What birds and animals offer us", he says, "is not confirmation of our sense of having an exalted place in some sort of cosmic hierarchy. It's admission into a larger scheme of things, where our minds are no longer turned in on themselves".

He concludes that "by giving us the freedom to see the world afresh, birds and animals renew our humanity".

Producer: Adele Armstrong.