Anthropologist Barbara King answers
Based on what science knows about animal emotion, as well as on my own two years of research into the data on animal grief, I’m struck most forcefully by what human grief shares with that of other animals. It’s not only elephant, chimpanzee, and dolphin survivors who may feel deeply the loss of their loved ones. There’s also altered behavioral routines and significant emotional distress—the main criteria I use to assess the presence of grief—that may be seen in farm animals like cows, pigs, and ducks, and in our companion animals ranging from horses and rabbits to cats and dogs. Depending on an animal’s personality and his or her relationship with the one who has died, the grief may be profound, and in some cases the survivors take months to recover (or never recover).
So what we share in common is the sorrow. Of course, there may be quite different cognitive underpinnings to grief, and variable ways to express grief, across species. Just as chimpanzee grief differs from duck grief, so is human grief unique in certain ways. As far as we know, no other species bears the full emotional weight of the knowledge that each one of us will someday die—even the most cherished beings in our lives, even ourselves. That degree of anticipation is unprecedented in the animal kingdom.
Further, we humans may grieve for strangers, those we have never met. We may be moved to tears by our extended sense of empathy for others—for example, when we learn of deaths across the country, across the sea, or halfway around the world. Ours is a collective species, and we come together at memorials in locations from Manhattan to Hiroshima to express sadness for those who never directly touched our lives. Elephants hint at this sort of generalized response because when a matriarch dies, members of different families come to the body and show evident distress; they grieve not only for their closest kin and friends. And perhaps my conclusion on this point is more correctly offered as a question for future research: To what degree do other animals grieve widely for their own kind?