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Grief Can Bring Personality Changes and Behavior Challenges in Pets

Updated: Jan 2

By: Eileen Koval, CDBC, CBCC-KA, CPDT-KA

Grief and sudden loss bring about deep and lasting emotions. It forces change upon us whether we want it or not. New situations require us to evolve as we piece together a life without a loved one. Anyone who has lost a sibling, a spouse, or close family or friend may understand this from personal experience. It is even worse when you live with that individual because the daily reminders of your loss are there throughout the day as routines change. Challenges come but that important support person is no longer physically there. This is no different for pets that lose a bonded sibling or a beloved human family member.

Our household has been going through this painful change, and consequently, we have had to make some big adjustments to support our sole remaining dog, Gilgamesh. He had never been an only dog and had navigated new situations throughout his life with older dogs by his side. We brought him into our home four years ago as a 10 week old puppy, already having two dogs in the home: Beowulf (1.5 years old) and his sister Bones (8.5 years old), all Kooikerhondjes. He immediately bonded inseparably with both of them. Unfortunately, we lost Beowulf to severe health issues in 2022 at just 4 years old, and then we suddenly lost Bones at 13 years old to hemangiosarcoma about six weeks ago. It has been a whirlwind of change for all of us over the past year and a half, but the change has been most radical for Gilgamesh.

Grieving is Unique and Cannot Be Avoided

Gilgamesh and Bones were not able to be there with us when Beowulf passed away last year. Despite not being there, they seemed to figure out quickly that he was not coming home when we came home devastated from the vet clinic. Days before Bones passed away, I ended up in the emergency room due to very low blood sugar. Our dogs have all been keenly aware and sensitive to my dips, spikes, and swings in blood sugar. We were also going through a month-long home renovation with numerous workmen inside our living space every day. Lots of stress going around. Then in the midst of all this, Bones suddenly passed away. She saw the best veterinarians during numerous recent vet visits for non-descript symptoms like reduced appetite, panting more frequently, having difficulty cooling off, and slightly pale gums. She had comprehensive bloodwork, multiple abdominal ultrasounds and radiographs that had all been taken in the previous month. Still, the hemangiosarcoma around her heart that spread to her lungs remained undetected until it ruptured. It is an extremely surreptitious cancer. Unfortunately, there are limits to what can be detected early and addressed with current medical knowledge, even with the best veterinarians and the best technology. Gilgamesh was with us by her side when she passed away. This may (or may not) have helped him understand what happened to her. But that was not the end of the grief. It was just the beginning of a tsunami of emotions and transformation.

Merely knowing for certain that a loved one has passed does not negate the grief. Attending a funeral is unfortunately not the end of the grief for anyone who has lost an immediate family member or close friend. The waves of grief continued to unravel as the days and weeks went on and we experienced life without them. Gilgamesh looked for Bones in the yard and inside the house on occasion, forgetting for a split second that she was no longer with us. We caught ourselves doing the same thing at times. Within a few days, his normally hearty appetite disappeared. He refused his meals, did not want treats, and he did not want to chew on the cow ears and bully sticks he previously enjoyed. One evening, he whimpered when he saw dogs on the TV screen. Previously, he had only selective interest – if not disinterest -- in other dogs. That changed overnight once he became an only dog. The one thing that he did seem to enjoy was getting out of the house on long walks and visiting new places.

Separation Distress/Anxiety

Additionally, Gilgamesh had hardly ever been truly alone. Usually, there was at least one other dog at home whenever we left for work or to run errands, but even that was infrequent. With our mismatched work schedules, someone was often home with the dogs anyway, so he had little experience being truly alone in the home. Still, I knew this day was coming even before Bones passed away. A few months before she passed away, I actually started a bit of separation desensitization training with him. As far as we knew she was healthy at the time, but I knew that she was getting older and at some point, he was going to need to be alone. I had Bones follow me going back and forth to the front door going through a separation to departure cues protocol, and eventually we progressed to walking outside away from him for brief periods, gradually increasing the amount of time. She did not understand what we were doing but knew there were treats in it for her! She was helping me prepare her brother for when she would no longer be there with him. It was a sad thing to think about.

The training helped a lot and he progressed, but it was not enough once she passed away and the new reality hit him hard with anxiety. When we tried to leave one day, he began howling as soon as he heard the deadbolt lock on the front door. We decided from that point forward that someone would always be home with him until we could bring down his baseline anxiety. He was not just anxious when we would try to leave. He was anxious even when we were still home at this point because he was still going through the different stages of grief and adjusting to change. The evenings seemed especially difficult for him when we would all try to relax and he seemed unable to do so. Only once he was more emotionally stable and less anxious would we start working on the separation anxiety again.

Identifying Needs, Creating New Routines, Plans

Addressing Needs First, and then Address Behavior

We came up with a plan moving forward to address his grief and anxiety, and to help develop new confidence and independence. Shortly after she passed away, he began taking Zylkene (a milk protein-based nutraceutical) and Purina Calming Care probiotic in the mornings, and Adaptil pheromone spray in the evenings when needed. He was having gastrointestinal issues, likely from stress and not eating consistently due to his sudden refusal of food . With the new schedule, each day started with a long walk immediately after we woke up. Then he was offered his food and Purina Calming care, which we were able to get him to eat sprinkled on top of some canned green beans. We also started measuring out the food that we wanted him to eat during the day and offered it several times per day. We introduced fun new training enrichment games at various points throughout the day to stimulate his mind. We gave him small “jobs” around the house when he was not sleeping and seemed restless. His mood seemed to boost while doing the training, so we were able to feed little bits of his food here and there during these happier moments.

While we would like to get back to set meals times in the future (we are easing into this now), his physiological needs come first. He really needed to eat, and like anyone going through grief he lost his appetite. He needed to be physically well in order to deal with everything, so getting him to eat was taking priority. He also needed a new routine since it changed with losing his sister – as well as some fun things to boost his mood -- so the enrichment training games checked all of these boxes. We also enrolled him in two of my group classes – Canine Good Citizen obedience and Agility -- with my husband putting in work scheduling requests so he could be available to work with Gilgamesh in the classes. In addition to the long morning walk, we began doing either a long walk in the evening when he had difficulty relaxing, or alternatively, going to meet up with friendly dogs. Either way, he was getting to sniff, see people and dogs, and meet his social and physical needs. His schedule was busy with lots of little enrichment here and there throughout the day and additional exercise. We still struggled with his appetite, but it slowly got better over time.

Reward-Seeking and Frustration Behaviors

As we experience depression, we begin seeking social connections, pleasureful activities, happiness…things that will lift ourselves out of the pain. The seeking system in the brain is a dopamine-driven network. Humans and animals NEED these things to help bring back equilibrium in the mind and body. For me, kettlebell sport lifting and being in nature helped me when Beowulf and Bones passed away. For Gilgamesh, this meant taking him to see other people and dogs to make new social connections. We began taking him to meet other dogs his around his size or smaller and he seemed satisfied for a period of time with meeting other dogs several times per week. After these social events he would be calm and relaxed. Eventually, his responses to these social events changed. He did not seem fulfilled no matter how many dogs he had met or how long he had greeted any individual dog. He actually seemed more wired and showed stress signs that this frequent social outing in the evenings was no longer a positive aspect of his life.

He did not want to walk past another dog without getting to say “hello”. He became overly fixated on every dog he saw, and began crying and whimpering on leash, pulling hard straining on the leash to try to get to them. We had never seen this sort of behavior from him before, but it should not be surprising. When someone is stressed or anxious, they may be less able to regulate emotions. I frequently see stressed or anxious animals become frustrated more easily because their coping skills are reduced. The way he was approaching dogs when over-aroused was not good. He came on too strong and was a flurry of over-excitedness. No one wants someone like that in their face. But it was not a symptom of an unmet social need because it did not matter how many dogs he met, or even if he had just met the dog. He still would not calm down. He was just overly fixated on dogs and over aroused by their presence. We began working on calm behavior around other dogs and creating value in ignoring them, while still letting him meet and play with the occasional dog. Just not most dog. We shifted his expectations to be around other dogs/people, but not necessarily expecting to interact directly with them. Again, it was frustrating for us but just another stage of going through all the grief and how anxiety/stress limits our ability to deal with situations. He has calmed down significantly and seems happier again – no longer showing as many stress signs like pacing, panting, fixation and lunging, whimpering, etc. – since we have continued going out to social situations but shifted the expectation (and associated reward). The reward was not in meeting dogs/people, but getting to watch them and smell what had been around, getting rewards for focusing on us, and maybe meeting the occasional dog/person.

We can become overly drawn to certain activities that provide pleasure to where it is almost addictive and no longer a healthy activity. There has been extensive research in humans and animals into how pain (including pain associated with grief) can activate the reward center of the brain (the dopamine-driven SEEKING system according to neuroscientist Jaak Panksepp) as we try to alleviate the pain we are feeling. This seemed true for Gilgamesh, and consistent with other dogs I have worked with experiencing intense physical – or emotional – pain. We used to see that with Beowulf when he was having very painful episodes with his IVDD, and he would become laser-focused on certain rewarding things or activities in the environment, like food, getting to a certain spot to smell, or engaging in breed-specific motor-patterns (like chasing something or performing guarding behaviors at a property boundary). He would become over-aroused very easily because of the pain and became frustrated easily. The same was true for Gilgamesh and his intense emotional pain. It was as if pain did not matter anymore as he would try to engage in activities that had to be physically painful. This is why we have to be especially careful with monitoring dogs for physical injuries, particularly working or sport dogs. They usually continue to try to engage in rewarding things, even in spite of intense physical pain, and the fact that they are in pain may trigger them to want to engage in these activities even more. They can be quite clever at masking these signs of pain, too.

As for Gilgamesh, he seemed to calm down in our home about six weeks after she passed away. The home renovations were finished and he had adjusted to the new routine and was also eating more consistently. At that point, we began working on the separation anxiety again using slow desensitization. He is making good progress, although there is still more progress to be made. Each day is getting better and better for Gilgamesh, and for us. We seem to have a good handle now on what he needs to balance his stress with positive emotions, positive experiences. Ultimately, he is gaining his confidence and independence back.

Why Not Just Get Another Dog?

We have been asked frequently why we did not just get him another dog, but that really would not have solved the issue. The pain from the loss of a spouse, significant friend or a beloved family member does not go away by simply finding a “replacement”. No one can replace them, even as we make new social connections. It is not the same. He may or may not have bonded with any new dog if we were to bring one home. Bringing another dog into the home introduces a variety of additional stressors. In the case of dealing with loss, the existing pet in the home may already feel that life is unstable and have a reduced capacity to deal with additional change and stress. This can create a ripe environment for behavior issues as an existing pet would have to share the owners’ attention, toys/food/space/resources, and learn to navigate social situations with this new dog whom they may or may not actually like. There is usually less focus on the existing pet from owners when a new dog is brought into the home because a lot of attention goes to the new puppy/dog. When dealing with loss, the existing pet often needs a lot more support and attention from their humans. A new puppy would have been a nice distraction but it would not have taken away the grief or given Gilgamesh the confidence he needed. He needed a chance to figure himself out and work through the anxiety, and only then can we figure out major changes for the future, like bringing in a new dog. No matter who we are we go through the stages of grief and loss in our unique ways. With dogs, we may see it come out in odd behaviors, such as changes in eating habits, difficulty controlling arousal, frustration behavior, new behaviors around noises/people/dogs, changes potty habits, etc.

We all miss Bones and Beowulf very badly, but our individual relationships with them were each unique, and respectfully different than the relationships Gilgamesh had with them. He looked at them as his sweet grandma and his fearless big brother. He relied on them and their responses to gauge how he felt about and how he responded to new situations. Like a lot of younger dogs (and kids), he took cues from them. Even still, interactions with my husband and I have also evolved as the family dynamics have changed. He is more cuddly, playful, more outgoing, and more engagement-seeking with both of us than before. He used to be playful and engagement seeking, but also sometimes had aloofness and a need for his own space like a lot of Kooikerhondjes. Experiencing a profound loss undoubtedly affects other social relationships and family dynamics, and can even affect personality. He is also accepting and interested in positively engaging with most other dogs now. Previously, he was less interested in social engagement with other dogs and less socially outgoing overall. He is more easy-going and has built significant confidence and resiliency as he has gone through rapid change in the past year and a half.

We are learning with recent scientific research that mammals, including dogs, grieve similarly to humans. My advice to anyone in a similar situation is to do your best to figure out what your pet needs. Be flexible. What they need from us may change as the days and weeks progress after losing their beloved fellow pet or beloved person. Grief comes in stages. Give them the time, support, and patience you yourself would want if going through a similar loss.


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Eileen Koval, CDBC, CBCC-KA, CPDT-KA, MSc (in Operations Management) is a fully certified dog behavior consultant with the International Association of Animal Behavior Consultants (IAABC). She believes the foundation of a good cross-species relationship is understanding the needs and normal behavior patterns of each dog as an individual, as he/she was bred to be. She enjoys helping humans and dogs communicate more effectively to create brilliant relationships with joy, purpose, and fulfillment for all species involved. She offers private consulting for serious dog behavior issues, obedience/manners, and agility training. Eileen developed a unique online course to help pet parents and trainers develop reliable snake avoidance behavior off-leash through positive reinforcement techniques. These techniques have been applied by trainers worldwide to teach dogs reliable avoidance of dangerous environmental hazards and off-leash property boundaries. She lives on a small ranch in Las Vegas, Nevada with her husband and their Nederlandse Kooikerhondjes.



Kakarala SE, Roberts KE, et al. The neurobiological reward system in Prolonged Grief Disorder (PGD): A systematic review. Psychiatry Res Neuroimaging. 2020 Sep 30; 303:111135. doi: 10.1016/j.pscychresns.2020.111135. Epub 2020 Jul 3. PMID: 32629197; PMCID: PMC7442719.

Panksepp, Jaak. Affective Neuroscience: The Foundations of Human and Animal Emotions. Oxford University Press; 1st edition. September 2004.

Uccheddu, S., Ronconi, L., Albertini, M. et al. Domestic dogs (Canis familiaris) grieve over the loss of a conspecific. Sci Rep 12, 1920 (2022).

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