Happy, a captive elephant, currently has a petition filed on her behalf for a common law writ of habeas corpus (that is, against unlawful and indefinite imprisonment) in the New York Supreme Court. Those who filed the petition are demanding recognition of Happy’s legal personhood and fundamental right to bodily liberty. But what is legal personhood? What does it mean to be a "person"? To answer these questions I'm joined by Dr Joe Wills of the University of Leicester, expert in human rights, animal rights and legal, political and moral theory.