I’ve been thinking about grief lately. It can be so overpowering – the dull ache of emptiness, the stabbing pain of loss, and the prism of sadness that transforms the bright colors of everyday life into a harsh and alien landscape. Consumed by grief, we are alone; yet somehow our solitary suffering can end up strengthening the bonds we have with others we know and love.

I’ve also been thinking about grief in animals, and what we know about it. When our cat Puggsley died, our younger Siamese, Moose, felt the full impact of the loss. The two had always been close, perhaps tied together by their mutual skepticism over Wednesday, our third cat and official people-pleaser. Moose and Puggsley were constant companions, playmates, napping buddies, and a rather frightening pair of mischief makers. When Puggsley became old and frail, he would curl up stiffly by the fireplace, and Moose would bed down near him. At the very end, Moose was right there, tenderly licking Puggsley as he was overcome by a seizure. And after he was gone, she mourned – she was lost without her friend, and had little appetite or energy for weeks. She never bedded down by the fireplace again. How do I know this was grief? Well, it was obvious; I just know.

Puggsley and Moose

But what do we really know about grief in animals – that is, in a scientific sense? Not particularly much, it turns out.

We are (mostly) beyond the era in which animals were considered thoughtless automatons, incapable of feeling pain and other emotions. Still, there have been relatively few formal studies of how animals experience grief.

In a way, this isn’t so surprising. For one, opportunities to systematically observe grieving behavior in the wild are rare and, if you think about it, it’s difficult to design ethical studies intended to cause social animals to grieve in captive settings. Also, what specifically do you test for and how do you quantify and evaluate an inherently subjective experience like grief? It’s tough enough to evaluate this sort of thing in humans, who can respond to questionnaires and use language to express their emotions….

As a result, most the scientific literature about grief in animals is anecdotal or observational in nature, and in many of these accounts it’s clear that otherwise objective researchers have struggled to come up with scientific ways of reporting what, in the end, are their own reactions, what they just know.

Although the record is sparse everywhere, there have been some recent papers on grief in primates. Brian Switek, who writes the Laelaps blog for Wired Magazine, has written a terrific piece on this research in his “What Death Means to Primates” posting (I strongly encourage you to check out Laelaps; it’s one of the best blogs out there on paleontology, evolution, and the history of science).

As Brian recounts in detail, studies have documented chimpanzee and other primate mothers who have continued to carry dead infants, sometimes for weeks and even to the point of mummification. In one of the studies¹, researchers described two chimpanzee mothers (Jire and Vuavua) in Bossou, Guinea, who carried their dead babies (aged 1.2 years old and 2.6 years old, respectively) after they had died in a respiratory epidemic, grooming them regularly, chasing away flies, and carrying them during all travel. The researchers pondered:

An obvious and fascinating question concerns the extent to which Jire and Vuavua “understood” that their offspring were dead. In many ways they treated the corpses as live infants, particularly in the initial phase following death. Nevertheless they may well have been aware that the bodies were inanimate, consequently adopting carrying techniques never normally employed with healthy young (although mothers of handicapped young have also been known to respond appropriately).

In another study², James Anderson, Alasdair Gillies and Louise Lock reported on the peaceful death of an older chimpanzee, Pansy, who lived in a safari park. They videotaped the reactions of Pansy’s companions and observed a number of behaviors that they found to be comparable to human bereavement. The degree to which the researchers sought out human counterparts to the chimps’ behavior is evident from the following description in their paper:

During Pansy’s final days the others were quiet and attentive to her, and they altered their nesting arrangements (respect, care, anticipatory grief). When Pansy died they appeared to test for signs of life by closely inspecting her mouth and manipulating her limbs (test for pulse or breath). Shortly afterwards, the adult male attacked the dead female, possibly attempting to rouse her (attempted resuscitation); attacks may also have expressed anger or frustration (denial, feelings of anger towards the deceased). The adult daughter remained near the mother’s corpse throughout the night (night-time vigil), while Blossom groomed Chippy for an extraordinary amount of time (consolation, social support). All three chimpanzees changed posture frequently during the night (disturbed sleep). They removed straw from Pansy’s body the next morning (cleaning the body). For weeks post-death, the survivors remained lethargic and quiet, and they ate less than normal (grief, mourning). They avoided sleeping on the deathbed platform for several days (leaving objects or places associated with the deceased untouched).

With this focus, it’s not surprising that they concluded by proposing that “chimpanzees’ awareness of death has been underestimated.”

Also, more anecdotally, many were moved by the apparent grief captured in this poignant National Geographic photo of chimpanzees at a rehabilitation center peering at the lifeless body of Dorothy, their long-time companion, being taken to her burial:

Chimpanzee burial (National Geographic, photo: Monica Szczupider)

There has also been some research into the behavior of elephants towards the dead and dying. In one study³, Iain Douglas-Hamilton, Shivani Bhalla, George Wittemyer and Fritz Vollrath reported on the death of Eleanor, a matriarch elephant in the Samburu National Reserve in Kenya. They were able to use GPS technology to track the movements of elephants in Eleanor’s family and in other families as they reacted to her collapse and subsequent death. The researchers found that Eleanor was visited frequently by both related and unrelated elephants, concluding:

Combined with earlier work and the data of other scientists it leads to the conclusion that elephants have a generalized response to suffering and death of conspecifics and that this is not restricted to kin. It is an example of how elephants and humans may share emotions, such as compassion, and have an awareness and interest about death.

Grace visiting Eleanor's body (photo: Douglas-Hamilton, et al)

In another paper⁴, Karen McComb, Lucy Baker and Cynthia Moss described experiments in which they assessed elephants’ strong interest in and sometimes dramatic reactions to elephant bones and tusks. After systematically presenting elephants in Amboseli National Park in Kenya with different combinations of elephant and other animal skulls, ivory and pieces of wood, the researchers found that the elephants were significantly more interested in elephant skulls and tusks than they were in the skulls of other animals or in the wood, but that they did not demonstrate a special affinity to the skulls or ivory of deceased relatives. The following video provides a nice glimpse into the way in which elephants seem to be fascinated by elephant bones and tusks:

…

Several reports have also documented cetaceans reacting with apparent grief. In one report⁵, for example, Mark Simmonds described an incident in which two male orcas appeared to grieve over the death of a female orca thought to be their mother. For years, the two males had spent all their time swimming with this female. After her death, the males were seen swimming together but apart from all other orcas for a day or two, repeatedly visiting the places that their mother had passed in her last few days. In another instance, Robin Baird of the Cascadia Research Collective reported seeing two orcas, a mother and adult son, swimming with a dead calf in the Puget Sound, with the mother balancing the calf on her rostrum or carrying it on top of her head and occasionally lifting it out of the water, and both adults diving deep to recover the baby when it began sinking.

Dolphin and calf (Tethys Research)

Scientists at the Tethys Research Institute related a similar occurrence off the coast of Greece, where a mother bottlenose dolphin was seen interacting with a dead newborn calf. Their description vividly underscores the difficulties in evaluating these sorts of situations from a scientific perspective:

Whilst researchers must avoid being driven by their own feelings and make arbitrary interpretations, in this case it was quite clear that the mother was mourning. She seemed to be unable to accept the death, and was behaving as if there was any hope of rescuing her calf. She lifted the little corpse above the surface, in an apparent late attempt to let the calf breath. She also pushed the calf underwater, perhaps hoping that the baby could dive again. These behaviours were repeated over and over again, and sometimes frantically, during two days of observation.

The mother did never separate from her calf. From the boat, researchers and volunteers could hear heartbreaking cries while she touched her offspring with the rostrum and pectoral fins. Witnessing such desperate behaviour was a shocking experience for those on board the research boat.

Finally, Marc Bekoff (he of the Yellow Snow fame) has written an eloquent article that includes many additional anecdotes regarding animal grief in his Psychology Today column.

Ultimately, there is much we will never be able to understand regarding how animals experience the world. We can trace commonalities between human and other animal brain structures and neural pathways associated with emotional experiences, and we can try to add more systematic observations to our collection of behavioral anecdotes, but in some fundamental ways the animal mind (and, for that matter, the mind of other humans) will always be cloaked in private experience, inaccessible to us. Moreover, as some of the accounts in this post have illustrated, our attempts at understanding animal emotions are inevitably colored by our own human experiences. We can know human grief, but how can we understand what it means to experience chimp grief, or elephant grief, or orca grief?

Nevertheless, just because we cannot fully comprehend what we see in other animals, that does not mean that grief in animals does not exist or that animals cannot lead rich emotional lives. Indeed, what we do see is a pattern that makes it increasing clear that death can impact other animals profoundly.

How do I know this? Just ask Moose, Puggsley or Wednesday – I just know.

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¹Biro, D., Humle, T., Koops, K., Sousa, C., Hayashi, M., & Matsuzawa, T. (2010). Chimpanzee mothers at Bossou, Guinea carry the mummified remains of their dead infants Current Biology, 20 (8) DOI: 10.1016/j.cub.2010.02.031.

²Anderson, J., Gillies, A., & Lock, L. (2010). Pan thanatology Current Biology, 20 (8) DOI: 10.1016/j.cub.2010.02.010.

³Douglas-Hamilton, I., Bhalla, S., Wittemyer, G., & Vollrath, F. (2006). Behavioural reactions of elephants towards a dying and deceased matriarch Applied Animal Behaviour Science, 100 (1-2), 87-102 DOI: 10.1016/j.applanim.2006.04.014.

⁴McComb, K., Baker, L., & Moss, C. (2006). African elephants show high levels of interest in the skulls and ivory of their own species Biology Letters, 2 (1), 26-28 DOI: 10.1098/rsbl.2005.0400.

⁵Simmonds, M. (2006). Into the brains of whales Applied Animal Behaviour Science, 100 (1-2), 103-116 DOI: 10.1016/j.applanim.2006.04.015.