Unless you happen to be an immortal hydra or a self-regenerating jellyfish, you can be certain that sooner or later your number will be up. The poignancy and finality of our mortal bucket-kicking is something that is not lost on humans, generating a range of complex emotions, although exactly how well other species understand the concept of death is somewhat unclear.

However, researchers from the University of Kyoto recently observed an alpha male snub-nosed monkey tenderly nursing a dying mate before apparently grieving after she died, suggesting that “empathy and compassion surrounding death extend beyond humans and their closest evolutionary relatives” to other types of monkey.

Examples of complex emotional responses to death have previously been observed in great apes, most notably chimpanzees, who are among the most closely related species to mankind. Other monkeys, such as marmosets, have also been seen displaying what may be interpreted as grief following the accidental death of one of their group.

However, with so few documented instances of this type of behavior occurring in the animal kingdom, it is still very difficult to say which creatures – if any – truly understand the significance of their companions cashing in their chips.

Yet James Anderson, whose team reports the touching behavior of this grief-stricken snub-nosed monkey in the journal Current Biology, told New Scientist that “the adult male and other members of his unit understood the dead female was no longer alive,” adding that “it seems likely that in long-lived species such as many primates, repeated exposure to death within the group leads to an understanding of the irreversibility of death.”

In a heartbreaking blow-by-blow account of events, the study authors report how the female monkey, known simply as DM, fell from a tree at 3.35 p.m. on December 17, 2013, “her head striking a stone as she hit the ground.” As she lay dying for the next 50 minutes, the group’s alpha male – referred to as ZBD – and the other females in the group surrounded her, “grooming and embracing her, and gently pulling her hand.”

^{The tragic sequence of events, beginning with DM's fall from the tree and ending with ZBD looking forlornly towards the spot where she died. Bin Yang, James R. Anderson, and Bao-Guo Li/Current Biology 26}

Once DM had drawn her final breath, the other females left the scene, yet ZBD remained by her side for several minutes, gently grooming her. After he had left, a researcher removed the body and buried it, yet the following day ZBD and his females returned to the spot where DM had died, where they let out warning calls to nearby individuals – a clear sign of distress.

Explaining this reaction, the researchers claim the emotional response of ZBD and the other group members was likely provoked by a range of factors, including the shocking nature of DM’s accident as well as the emotional connection she had with ZBD, having had an infant together.

Eulogizing the emotional depth of the monkeys, Anderson concludes that “there’s now enough evidence from observations of responses to dying group members in species such as chimpanzees, elephants, and dolphins to suggest that empathy and compassion occur in these species, and now in snub-nosed monkeys.”