Anyone who has more than one dog might have seen it unfold: A beloved pet dies, and the remaining dog seems to suffer as deeply as the rest of the family.
Now, new Italian research adds to evidence that man's best friend does indeed mourn such a loss.
Eighty-six percent of 426 dog owners who had lost one of their animals said their surviving dog went on to display negative behavioral changes for months. Those changes included playing and eating less, sleeping more, becoming more fearful, and tending to whine and bark more often.
But does this all add up to canine grief?
"Overall, demonstration of grief in non-human animals is one of the biggest challenges facing science," acknowledged study author Dr. Federica Pirrone. She's a lecturer of veterinary ethology and animal welfare in the department of veterinary medicine and animal science at the University of Milan.
Pirrone noted that "other social species -- such as great apes, whales, dolphins, elephants and birds -- have been described to engage in death rituals in which one could see the expression of grief."
But "emotions, particularly complex emotions like grief, are still a shady, and thus intriguing, side of the lives of domestic dogs," she said. "At least for us humans."
To gain better insight into canine grief, the study team administered a questionnaire to 384 women and 42 men who had lost a dog relatively recently.
On average, the dogs who died had been in the owner's household for nearly 10 years, and in just over half the cases their death happened unexpectedly.
More than 9 in 10 said their surviving dog had lived with the dog who had died for at least a year, and many said that activity sharing was common: two-thirds of the dogs had slept together; more than a quarter had groomed each other; half had played with each other; and more than half (54%) had never fought. Just over a third also shared their food, nearly 60% shared their toys, and 86% shared resting areas.
After one dog died, behavior changes were common among the surviving dogs, the team found, with only about 13% of owners seeing no changes in habits.
For example, attention-seeking shot up among two-thirds of surviving dogs, while 57% started to play less often. Overall activity levels dropped among 46% of dogs, with roughly a third tending to sleep more, eat less and/or be more fearful. Three in 10 dogs barked and whined more.
The team did find that the risk for behavior changes went up the more an owner grieved.
In the study, "the level of fear in the surviving dog was positively correlated with [the] owners' level of suffering, anger and psychological trauma," Pirrone said.
The findings were published Feb. 24 in the journal Scientific Reports.
Patricia McConnell, a certified applied animal behaviorist, reviewed the findings and thinks all the changes cited in the study do, in fact, add up to expressions of canine grief.
"I'm gratified that the study was done, because it frankly seems impossible that dogs wouldn't grieve," said McConnell. "They are highly social, some of the most social mammals in the world. And as mammals, they share much of the same neurobiology and physiology that drives our own emotions."
What should you do if one of your dogs dies?
Pirrone advised maintaining routines and staying close to the surviving dog, to "make them feel protected."
But McConnell cautioned that -- as with human grief -- there's no quick "fix."
In advice she shares online, McConnell encourages owners to give themselves the space to grieve as well, even while knowing that "dogs can be extremely sensitive to your suffering and feel powerless to 'fix' it themselves."
McConnell also suggests spending time "talking" to your dog to maintain a connection, while also striving to follow a blend of old daily routines and new stimulating activities.
But in the end, she said, "dogs need something similar to what we need: gentleness, caring concern and time, time, time."
There's more on human-pet relations at U.S. Department of Health and Human Services.
SOURCES: Federica Pirrone, DVM, PhD, lecturer, veterinary ethology and animal welfare, department of veterinary medicine and animal science, University of Milan; Patricia McConnell, PhD; certified applied animal behaviorist and expert, companion animal behavior and the biology and philosophy of human/animal relationships, and adjunct professor, zoology, University of Wisconsin-Madison; Scientific Reports, Feb. 24, 2022