After Rosie’s mother died, she accompanied the lifeless body throughout the night, in apparent mourning. When Noel lost her adopted son, she picked his teeth clean with a grass stem. And Jire carried her infant’s corpse for 68 days after the one-year-old succumbed to a respiratory infection.

Rosie, Noel and Jire are chimpanzees, whose responses to death were documented by researchers. Their behavior makes one wonder: Do chimps and other animals understand death, or are humans the only spe