Why do some chimpanzee mothers carry their dead infants for months?

Chimpanzee and bonobo mothers sometimes continue to carry their infants after they die, a behaviour known as infant corpse carrying (ICC). University of Oxford research found that older infants, who were more closely bonded with their mothers, were carried for longer than younger infants. The results suggest that the strong social bond between chimpanzee mothers and their infants drives ICC.