Mama, 59 years old and the oldest chimpanzee and the matriarch of the famous chimpanzee colony of the Royal Burgers Zoo in Arnhem, the Netherlands, was gravely ill. Jan Van Hooff (emeritus professor behavioral biology at Utrecht University and co-founder of the Burgers colony) who has known Mama since 1972, visited her in the week before she died of old age in April 2016.