What Do Animals Know and Feel About Death and Dying?

A collection of essays offers a thorough review of evolutionary thanatology.

Posted Feb 24, 2020

Evolutionary and comparative animal thanatology

I've long been interested in the wide variety of ways in which nonhuman animals (animals) grieve and mourn the loss of others. I'm pleased to share that a comparative, comprehensive, and valuable review on the topic has been published in a collection of original essays in a special issue of the journal Primates (available online). The essays are listed below for convenience, along with a few brief summaries, and this information alone shows just how incredibly exciting this field of research has become.1,2 

To begin with, Kyoto University professor of psychology Dr. James Anderson, who organized the collection of essays in Primates, offers a thorough review of the ever-growing field of evolutionary and comparative thanatology—the study of death and dying in nonhuman animals—along with a summary of the original essays in a piece called "Responses to death and dying: primates and other mammals."3 He begins:

"Although some definitions of thanatology—broadly definable as the study of death and dying—exclude nonhumans as subjects, recognition of the scientific value of studying how other species respond to sick, injured, dying, and dead conspecifics appears to be growing. And whereas earlier literature was largely characterized by anecdotal descriptions and sometimes fanciful interpretations, we now see more rigorous and often quantitative analysis of various behaviors displayed towards conspecifics (and sometimes heterospecifics) at various stages of incapacitation, including death." 

This collection of essays that center on a common theme is unprecedented, and below are some snippets to whet your appetite for more information about a fascinating field of study. I begin with elephants because an essay in the Washington Post by Jason Bittel titled "An elephant’s story does not end when it dies" covers some of the information that's included about these magnificent, smart, and emotional giants, for whom there are numerous stories about the ways in which surviving individuals grieve and mourn dead companions. His essay is about Victoria, a 55-year-old matriarch who died in June 2013 and included quotes from the authors of the essay on which it was based that appeared in Primates called "Elephant behavior toward the dead: A review and insights from field observations" by elephant experts Shifra Goldenberg and George Wittemyer.

Free stock photo by Jooinn
Source: Free stock photo by Jooinn

The discussion of elephants is an excellent place to focus, because similar to other scientists whose work also is covered in the journal, the elephant researchers themselves remain cautious about what we really know about the thoughts and feelings of surviving elephants.

In their research paper, they write: "Elephants show broad interest in their dead regardless of the strength of former relationships with the dead individual. Such behaviors may allow them to update information regarding their social context in this highly fluid fission-fusion society. The apparent emotionality and widely reported inter-individual differences involved in elephant responses to the dead deserve further study."

In Mr. Bittel's piece, he writes: "The scientists do not conclude from these accounts that elephants mourn, an activity that is often attributed to the species. But their response has a common thread, the authors say. When an elephant falls, the loss is acknowledged and investigated by other elephants, even those unrelated to the deceased. Death means something to elephants, in other words—possibly something emotional." (My emphasis.)

The lead author of the research essay, Shifra Goldenberg, notes, “We don’t know what’s going on in their heads." On the other hand, another elephant expert, Joyce Poole, whose observations of elephants were summarized in "Elephant behavior toward the dead: A review and insights from field observations," openly attributes emotion to the grieving elephants to the behavior patterns we observed in survivors. 

Details about other essays can be found in James Anderson's piece in a section called "Papers in the special issue." Even if you don't have the time to read the essays themselves, this section is a goldmine of up-to-date information about what we know regarding evolutionary and comparative thanatology and the behavior patterns that various animals show when they interact with dead companions and other individuals. You can read about a variety of nonhuman primates, including wild gorillas, chimpanzees, monkeys, horses, and an essay on free-ranging Asian elephants that's the first scientific discussion of responses to dead and dying conspecifics (members of the same species). 

While some researchers aren't sure what we really know about what's happening in the heads and hearts of surviving animals when they interact with a corpse and still leave the door open to the idea that elephants and other animals don't mourn the dead, I side with Joyce Poole and others who feel comfortable in claiming that something emotional is going on in their minds. The detailed descriptions of the behavior of survivors in the essays in Primates and in the numerous references that are provided and elsewhere leave no doubt in my mind. 

Research clearly shows that other animals say goodbye to family and friends: Where to from here?

The material covered in the essays is very comprehensive, and it doesn't strain credibility to say that surviving individuals know something novelsomething very differenthas happened to an individual when they interact with their corpse. This is so, even if they may not conceptualize death in the ways that many, or most, humans do. For example, it's possible that the elephants who interacted with elephant matriarch Victoria's corpse didn't know she'd no longer be around, but it also remains possible that they did. At the moment, we really don't know.

The essays also don't focus on what a dying individual might know about themselves. (See, for example, "Do Dogs Know They're Dying?") However, while we don't know what they actually—precisely—know or feel about other individuals no longer around, or what they're thinking and feeling about their own demise, available data and countless stories clearly show they know and feel something.

This isn't surprising given solid evidence that the animals being discussed (and many others) have rich and deep cognitive and emotional lives. Also, the titles, abstracts, and content of the essays in Primates and in many other articles published elsewhere clearly show that something strong and deep is happening to them in response to others' corpses.

The many emails I received in response to "Do Dogs Know They're Dying?" without one exception contained compelling stories that the dogs about whom the people were writing (along with other animals who were brought into the picture) most likely knew they were dying. Some didn't waver one bit. I think it's entirely reasonable to keep the door open to this possibility. 

To sum up, here's a personal story about my very first encounter with some of the wild elephants at Samburu National Reserve about whom Shifra Goldenberg and George Wittemyer write. I drove out with a renowned elephant researcher, Dr. Iain Douglas-Hamilton, to where some elephants were spending the afternoon, and I could feel something was off, but I didn't know why. The elephants seemed lost. They were moping about, walking here and there with their heads hanging down, and I could literally see and feel their sadness.

I asked Iain what was happening, and he told me their matriarch had recently died. And in stark contrast, just down the road a few kilometers, there was another group of elephants who were clearly feeling OKjust as I had expected them to behave from having seen videos of wild elephants in different locales. The marked differences between the behavior of individuals in the first and second groups were riveting. To this day, I still remember how sad I felt for the grieving elephants when, at first, I had no idea why they were behaving as they were. I've also seen similar behavior in wild coyotes. 

The real question at hand is not if other animals grieve the loss of other individuals, but rather, why has grief evolved. We don't have any definitive answers to this question; however, there are a good number of interesting speculations. The why questions surely are difficult to answer.

However, when I talk with people about grieving and mourning in nonhumans, many are shocked that researchers and other academics still claim that we don't know if they miss and mourn the loss of family and friends. I side with them and find available data to be very convincing, I feel certain we're not the only occupants of the grief and mourning club. 

Stay tuned for further discussions on the fascinating field of study called evolutionary thanatology. Many bright-minded researchers are keenly interested in responses to death and dying in a wide variety of animals, and there's no shortage of stories from citizen scientists that focus on these topics.

Nothing is lost, and much will be gained by considering different explanations as data and stories pour in. And as we learn more about what other animals are thinking and feeling about death-related issues, we'll likely learn more about ourselves

References

Notes

1) Essays in the special issue of Primates and a few brief summaries:

Pettitt P, Anderson JR (2019) Primate thanatology and hominoid mortuary activity. Primates. ("In recent years, a thanatology of primates has become a respectable research topic, and although still sparse, observations among several taxa have shown how complex responses to the dead can be.")

Negrey JD, Langergraber KE (2019) Corpse-directed play parenting by a sterile adult female chimpanzee. Primates. ("Here, we report two cases from Ngogo in Kibale National Park, Uganda, in which a wild adult female chimpanzee (P. t. schweinfurthii) directed parental behaviors at corpses. Both cases involved the same adult female chimpanzee, aged 20–21 years.")

Takeshita RSC, Huffman MA, Kinoshita K, Bercovitch FB (2019) Changes in social behavior and fecal glucocorticoids in a Japanese macaque (Macaca fuscata) carrying her dead infant. Primates. (We hypothesize that dead infant-carrying may have evolved as a strategy to mitigate stress from infant loss. These findings have implications for our understanding of grief in nonhuman primates and can impact management protocols surrounding deaths in captive social groups.")

Trapanese C, Bey M, Tonachella G, Meunier H, Masi S (2019) Prolonged care and cannibalism of infant corpse by relatives in semi-free-ranging capuchin monkeys. Primates. ("After half a day of taking care of the dead infant, the mother ate part of the corpse’s skin and the highly nutritional viscera, possibly thereby compensating for the physiological costs of pregnancy.")

Mendonça RS, Ringhofer M, Pinto P, Inoue S, Hirata S (2019) Feral horses’ (Equus ferus caballus) behavior toward dying and dead conspecifics. Primates. ("Kin and non-kin of both sexes showed unusual interest in the dying foal. However, horses appeared to avoid dead conspecifics.")

Watts DP (2019) Responses to dead and dying conspecifics and heterospecifics by wild mountain gorillas (Gorilla beringei beringei) and chimpanzees (Pan troglodytes schweinfurthii). Primates. ("In response to calls for more information, I describe 25 cases of responses to corpses, skeletons, and mortally injured or ill individuals, both conspecifics and heterospecifics, seen during fieldwork on mountain gorillas (Gorilla beringei beringei) and chimpanzees (Pan troglodytes schweinfurthii).")

Lowe AE, Hobaiter C, Asiimwe C, Zuberbühler K, Newton-Fisher NE (2019) Intra-community infanticide in wild, eastern chimpanzees: a 24-year review. Primates.

Masi S (2019) Reaction to allospecific death and to an unanimated gorilla infant in wild western gorillas: insights into death recognition and prolonged maternal carrying. Primates. ("These observations show that non-predatory species, such as gorillas, may be able to acquire and develop some knowledge about death even though they do not kill other vertebrates.")

Goldsborough Z, van Leeuwen EJC, Kolff KWT, de Waal FBM, Webb CE (2019) Do chimpanzees (Pan troglodytes) console a bereaved mother? Primates

Jakucińska A, Trojan M, Sikorska J, Farley D (2019) Reaction to the death of the oldest female in a group of chimpanzees at the Municipal Zoological Garden, Warsaw. Primates. ("After ruling out several alternative explanations, we propose that many of the chimpanzees consoled the bereaved mother by means of affiliative and selective empathetic expressions.")

De Marco A, Cozzolino R, Thierry B (2019) Responses to a dead companion in a captive group of tufted capuchins (Sapajus apella). Primates. ("Most of the behaviors directed to the body of the deceased individual appeared to be investigative.")

Goldenberg SZ, Wittemyer G (2019) Elephant behavior toward the dead: a review and insights from field observations. Primates. ("Elephants show broad interest in their dead regardless of the strength of former relationships with the dead individual. Such behaviors may allow them to update information regarding their social context in this highly fluid fission–fusion society. The apparent emotionality and widely reported inter-individual differences involved in elephant responses to the dead deserve further study. Our research contributes to the growing discipline of comparative thanatology to illuminate the cognition and context of nonhuman animal response to death, particularly among socially complex species.")

Sharma N, Sharma Pokharel S, Kohshima S, Sukumar R (2019) Behavioural responses of free-ranging Asian elephants (Elephas maximus) towards dying and dead conspecifics. Primates. ("

Our observations indicate that, like their African counterparts, Asian elephants might experience distress in response to the death of conspecifics, and may have some awareness of death. This information furthers our understanding of the emotional and cognitive complexities of highly social elephants, and contributes to the growing field of elephant thanatology.")

2) More information about death and dying in a wide variety of animals can be seen here

3) Thanatology (or deathlore) is "the scientific study of death and the losses brought about as a result. It investigates the mechanisms and forensic aspects of death, such as bodily changes that accompany death and the post-mortem period, as well as wider psychological and social aspects related to death."

Anderson, James. Comparative Thanatology. Current Biology, 2016. 

Archer, John. The Nature of Grief: The Evolution and Psychology of Reactions to Loss. Routledge, New York, 1999. (For a critical review of this book click here.) 

Bekoff, Marc. A Grieving Gorilla: A Picture That's Worth Entire Courses

_____. Make No Mistake, Orca Mom J-35 and Pod Mates Are Grieving

_____. Donkeys: If They Aren't Grieving What Are They Doing?

_____. How Animals Grieve: Saying Goodbye to Family and Friends. (A review of How Animals Grieve.)

_____. Grief in Prairie Dogs: Mourning a Death in the Family.

_____. Grief, Mourning, and Broken Hearted Animals.

Bologna, Caroline. Pets Can Experience Grief. Here's What You Should Know About It.

Herzog, Hal. Encounters with Dead Pets: A Study of the Evolution of Grief

King, Barbara. Animal mourning. Animal Sentience, 2016. (A discussion of a wide variety of animals.)

Marzluff, John and Angell, Tony. Gifts of the Crow: How Perception, Emotion, and Thought Allow Smart Birds to Behave Like Humans. Atria Books, 2013.

Paretts, Susan. Do Dogs Grieve Other Dogs?