If anyone has any doubts as to the ability of chimps to show emotional connections, this touching moment should put any of those to rest. A 59-year-old chimp named Mama was gravely ill and refused food. Jan van Hooff, a professor of behavioural biology at Utrecht University, has known Mama since 1972. He decided to pay her a visit the week before she died of old age in April 2016. It takes a while before Mama becomes aware of Jan's presence, but when she does, her reaction is incredibly touching.