- Anecdotal evidence suggests that in multiple dog households, when one dog dies, the survivor shows grief related behavior.
- In a recent study, 86% of surviving dogs showed negative behavior changes following the passing of a canine housemate.
- Whether a dog shows mourning behavior seems to depend on whether there was a friendly relationship between the dogs in the house.
A number of years ago, I had a Cairn Terrier named Flint. When he was around five years of age we got a second dog, a Cavalier King Charles Spaniel, who we named Wizard. The two dogs were nearly the same height and weight, but when it came to characteristics and personality they were as different as chalk and cheese. Flint was a typical hyperactive, high maintenance terrier, constantly careening around looking for something to chase or bark at, while Wiz was easygoing, laid-back, and although he was observant, he was seldom moved to bark at anything. Both dogs were friendly and got along well. They both slept at the foot of my bed, often with their heads resting on my ankles. The two dogs were always together, in the house, in obedience training classes, or when we went out into the countryside.
A Canine Companion Passes Away
When Wiz was around four years of age, Flint died suddenly. I am sure that from Wizard's point of view it was simply the case that Flint was always there and then one day he was gone and never returned. At first Wiz simply seem to be puzzled and checked the places where Flint usually tended to rest, especially his favorite hideout under the end table next to the sofa. After a day or so Wizard's sense of loss seemed to increase and he would return to gaze at that place, and then plaintively whimper.
Wiz had always been an affectionate dog, however after the loss of Flint he became "clingy." Now he seemed to me to be seeking more than mere affection, something extra — like reassurance. At night he no longer was content to sleep at my feet, but rather moved upward in the bed and wormed his way under my arm. If I had to describe his behavior I would say that he was listless, confused, and (I am sure I am anthropomorphizing) depressed. It seemed to me that he was grieving the loss of his canine housemate.
I told some of my psychological colleagues that I believed that Wiz was mourning Flint's death. However, one developmental psychologist pointed out that since dogs have mental abilities which are similar to a young human child of age 2 or 3 years, this was doubtful. She said that it was unlikely to be actual grief since that would require some concept of the nature and implication of death, yet data suggests that that is beyond the mental capacity of human children until they reach the age of 4 or 5 years. That line of reasoning led her to the conclusion that it would be unlikely that dogs have the capacity to understand the concept of death. I understood the validity of what she was saying, but it was hard to shake the feeling that this truly was mourning behavior.
Gathering Data on Canine Grief and Mourning
Some years later I was approached by two Italian researchers, Federica Pirrone from the University of Milan and Stefania Uccheddu from the San Marco Veterinary Clinic and Laboratory in Padua. They were putting together an international team of a dozen researchers to study the question of whether dogs mourn. Because I felt the dogs did grieve for a lost housemate I gladly joined the team so that we could finally test this notion empirically. My role in the project was modest, with most of the heavy work being done by Federica and Stefania.
Nothing moves swiftly in research, and the first step required the development of the measuring instrument which we would use for our data collection. This took several years. First there was a pilot study, then a test sample of 369 people, followed by a whole mess of statistical analyses to select items that work and to validate the survey instrument. When it was finished we called it the "Mourning Dog Questionnaire."
After that we were ready to collect the actual data. This involved a new survey of 426 Italian dog owners who had owned at least two dogs, one of whom had died while the other was still alive.
The results were quite clear in some respects. Certainly the surviving dog is affected by the loss of his companion since 86% of the dog owners observed negative changes in the surviving dog's behavior. For many of these dogs, the behavior changes were of significant duration, since 32% reported that these lasted between two and six months and 25% reported that they lasted longer than six months.
What Are the Grief-Related Behaviors?
When we asked the subjects to describe the behavioral changes that they observed, 67% reported that the surviving dog became more attention seeking (much like the clingy behavior which I observed in Wiz). According to the reports, 57% reported that the dogs played less, and 46% reported that they were generally less active. Approximately 35% of the owners reported that the surviving dog slept more, and roughly 1 out of 3 dogs showed signs of increased anxiety and fearfulness. In addition, 32% reported that the dogs ate less and 30% reported an increase in whining or barking.
Quality of Relationships Matter
One surprise (at least for me) was that the length of time the dogs lived together did not influence whether the surviving dog showed mourning behaviors. However, the quality of the relationship between the two dogs was important. If the dogs were friendly toward each other the survivor was more likely to show grief. One important marker was whether the dogs shared food with each other.
Not as surprising was the fact that dogs were more likely to have negative behavioral changes and fearfulness when their owners showed more signs of suffering, grief, anger or psychological trauma following the death of their pet. This also provides a bit of an interpretive problem since the dog's behavior changes might be some form of social transmission in which they are responding to the mood changes in their owners rather than the loss of their companion.
Is It Really Grief?
Thus these data clearly show that in multiple dog households the death of one dog does have a behavioral impact — that is not in dispute. However, our team could not definitively say that the dogs are responding to the death of their companion or whether this is some form of separation anxiety due to the absence of their housemate. In the end, we are left with the same problems that developmental psychologists have when dealing with the definition of grief in young children. It is quite clear that there are behavior changes when a canine friend is removed from a dog's life, however, the interpretation of whether this is really grief or mourning is not straightforward.
Still, if I were to summarize our data in a single sentence I would say that when a dog loses a canine companion it seems to cause psychological pain in the surviving dog.
Copyright SC Psychological Enterprises Ltd.
Uccheddu, S., Ronconi, L., Albertini, M., Coren, S., Da Graça Pereira, G., De Cataldo, L., Heverbeke, A., Mills, D. S., Pierantoni, L., Riemer, S., Testoni, I., and Pirrone, F. (2022). Domestic dogs (Canis familiaris) grieve over the loss of a conspecific. Scientific Reports. DOI: 10.1038/s41598-022-05669-y.
Uccheddu, S., De Cataldo, L., Albertini, M., Coren, S., Da Graça Pereira, G., Haverbeke, A., Mills, D.S., Pierantoni, L., Riemer, S., Ronconi, L., Testoni, I., and Pirrone, F. (2019). Pet Humanisation and Related Grief: Development and Validation of a Structured Questionnaire Instrument to Evaluate Grief in People Who Have Lost a Companion Dog. Animals 2019, 9(11), 933; pp. 1-14. https://doi.org/10.3390/ani9110933