This week, the Chasers journey to America to pit their wits against Kanzi, a Bonobo ape who is able to communicate with humans by using a series of pictures and symbols on a Lexigram, and in addition to this is also thought to be one of the first Apes to show an understanding of spoken English. They also meet a chimpanzee memory wizard, a 25-year-old gamer orang-utan called Katie and that well-known genius of the ocean, the dolphin. And, using their hearts as well as their heads, they will confront the moral challenge: that if humanity fully understood animal intelligence, would we treat them differently?