On a river in southern Liberia are a series of islands with an unusual group of residents - a colony of 66 tame chimpanzees. Betsy Brotman knows how they got there. Betsy is an American scientist who moved to Liberia in 1974 to work in a laboratory that was developing a vaccine for hepatitis on behalf of the New York Blood Center. She used the chimps in tests, working with them for over 30 years - and caring for them during the country's civil war. When they were no longer needed for research the chimps were moved to their current home on the islands. Now in her seventies, Betsy has retired to her home state of New Jersey in the USA, where our reporter Colm Flynn met her.