In this touching video, Mama, a 59-year-old chimpanzee who was gravely ill, and wouldn't even accept food, soon recognizes a man that saved her.

Jan van Hooff, an emeritus professor of behavioural biology at Utrecht University and co-founder of the Burgers colony where Mama lived as the matriarch, has known Mama since 1972. He visited her in the week before she died of old age in April of 2016.

While it took Mama a little while before she noticed van Hooff, when she finally does, her reaction is very emotional and definitely heart-breaking.