There were no significant findings on the nerve/muscle biopsy that was sent to the University of California- San Diego.  The brain and spine showed no lesions that would have caused the neurological condition. This confirms the information that we gained by doing the MRI and spinal tap, which in itself is a significant component of this case as Boltz was the first wolf in our history that had both procedures.  The pathologist final report is yet to arrive.   I would say we had the best diagnostic team possible, but if I go back to the original discussion about Degenerative Myelopathy, the idea was, that if we ruled everything else out, that’s the likely cause.  The DNA test that we ran on Boltz showed the lack of the mutated gene for DM.  What I didn’t know (and now I do), is that the lack of the mutated gene wasn’t a diagnosis for DM but was indicative of a an animal being a carrier, not whether an animal had DM.  Our loss of Boltz is still fresh in our hearts.  The passing of each wolf is hard, but the lack of knowledge on the cause makes this particularly hard for staff.

Today, we take the time to remember Boltz, his legacy of knowledge and medical diagnosis that was a first for any of our wolves.  We also take today to honor Luna, who lost her battle to cancer on November 26, 2019.

RIP to these two, it was an honor to be one of your many social companions.

In an effort to give Denali and Grizzer some additional enrichment, we chose to feed them 2 deer legs on Saturday night.  We knew that Denali might be more food possessive, but with he and Grizzer both getting a daily meal of between 3 – 4 pounds of meat, we thought the added food could be enjoyed by both.   While Denali managed to gather both deer legs on the initial delivery, Grizzer was able to eat some of the meat and proved that he is still capable of guarding food (check out our latest youtube to see him in action).  This was great stimuli for Grizzer and a good distraction for Denali who is still not quite settled into retirement.  We have noticed that Denali is standing on top of the dens trying to see over the fences into the Exhibit.  We decided to open the gate in the pack holding area to allow the retirees a full view of the Exhibit Pack.  Of course, we reinforced the shared gate with 1/4 plate steel and additional fence panels to avoid any chance that a gate would be compromised.  Grizzer likes the ability to see the arctics, but Denali is still a bit intimidated.  Grayson has been at the fence with a high tail posture definitely indicating that his rank has increased since Denali’s retirement.

With Axel and Grayson being the only members of the Exhibit, we find Grayson’s dominance increasing.  For most of Grayson’s life, he has been lower ranking than his brother Axel, mainly due to Denali’s influence of controlling food resources.  Denali would allow Axel to feed without any issues, but would guard and drive Grayson away from food.  With Denali’s retirement, Axel and Grayson are exhibiting a lot of testing behaviors. According to the Center’s educators who get a front window view of the brothers on a daily basis, they recently observed two behaviors that demonstrate this testing process:
“Grayson went in for the world record of longest chin rests on Axel. Of course Axel responded to this with a drawn out ride up on Grayson. “
The peak activity seems to be during the morning wolf care sessions from approximately 8 am – 10 am and again during the last few hours of daylight from approximately 3 pm to 5 pm.  Viewers of our webcam may hear Grayson as he tends to display lone howls that switch between a low throated howl to communicate and a bark howl to identify a potential threat to the Exhibit.
As you may have read in the Center’s press release, we euthanized Boltz at approximately 7 a.m. on Nov. 12, 2020. His condition really declined in the last week, not only physically, but behaviorally.


While the lack of mobility and swaying of his back legs didn’t seem to elicit a pain response, he began to fall more frequently, began dragging his feet and he started to struggle to get up.  Initially, his mobility would noticeably decline when stress would seem to exacerbate the condition.  So we modified the wolf yard access, cancelled programs and did whatever possible to keep him calm. Surveillance video was reviewed each morning to assess how long he rested and his posture upon rising in the morning.


In the last few days, we saw a decline in mobility that was independent with any external activity in the wolf yard that may trigger stress.  Our biggest concern was that he would seriously injure himself falling as the colder weather and snow on Tuesday created icy conditions.  The other concern that is equally important as the physical was the psychological.  This condition seemed to cause confusion and panic when he didn’t have the strength to support himself.  His struggles were heartbreaking and we were helpless to find him any relief.


Boltz deserved better than to struggle and panic through this decline.

Since this condition was first identified on Aug. 23, he had a Thoraco-lumbar and brain MRI, CerebroSpinal Fluid cytology, CerebroSpinal Fluid infectious disease assessment, protein tests, cancer cell tests, and a genetic screen for Degenerative Myelopathy and all were inconclusive. We assessed and used possible treatments in the absence of a diagnosis in hopes that we would see some response or improvement.  Despite our Veterinarians dedicated efforts, we had no improvement.  When the decision was made to go forward with the USDA Animal Welfare Act Euthanasia protocol, we consulted with the University of Minnesota pathologist to discuss all sampling that could be performed at the necropsy and made sure we did everything possible to find an answer.  We also sent nerve and muscle biopsies to a specialist at the University of California San Diego Neuromuscular Lab.  Their reputation has been described as: “…an international reference center dedicated to the diagnosis and study of spontaneous neuromuscular diseases in companion animals. Specialized testing performed in this laboratory includes evaluation of muscle and peripheral nerve biopsies by state-of-the-art methods, immunohistochemistry, immunofluorescence staining and immunoblotting for the diagnosis of various muscular dystrophies and other congenital myopathies.”


As is standard protocol for any wolf mortality at the International Wolf Center, we did allow all the remaining ambassador wolves to see and smell the body through the fence.  This has been a practice recommended by our Veterinarian years ago to help the other wolves process the loss of a pack member.  All the wolves showed interest, but Grayson had the strongest whining and licking response, and had a significant amount of bark howling throughout the day.  Staff spent time with Grayson to help calm him and also transitioned Grizzer and Denali into the Pack Holding Area where Boltz had been residing. Boltz’s body will be cremated at Pets Remembered in the Twin Cities and his ashes will be spread with his pup mate Luna’s, who succumbed to cancer on Nov. 26, 2019.


I am grateful to all of the people who emailed me with comments, suggestions and their own pet’s medical histories.  I wish we had more time to try every procedure, but without any diagnosis, we couldn’t let him suffer without any treatment nor continue with invasive procedures that had limited outcome.  We hope to learn of his condition through the final necropsy and tissue samples provided.  Boltz’s legacy will be to help us learn all that we can about his condition and serve the ambassador wolves to the best of our ability for generations to come.


– Lori Schmidt

Despite an extensive amount of diagnostic testing, research and treatments, Boltz continues to decline from his neurological condition.  On his Monday morning vet check, the wolf care staff discussed quality of life issues and efforts are being made to keep him comfortable and calm as the next steps of the USDA Animal Welfare act protocol are addressed.

Boltz completes his treatment for Myasthenia Gravis on Sunday.  Unfortunately, there were no improvements seen in a week of treatment.  We are preparing the USDA quality of life assessment that includes a behavioral assessment of alertness, pain response, social engagement, willingness to take food, tolerance of ambient temperatures, lack of tolerance for environmental changes and climatic stresses, ability to rest and impact of medical condition to behavioral stress.  To accomplish this, we rely on our surveillance cameras, monitoring when he goes into the den at night, when he first rises in the morning and if there are instances where he rises during the night.  At this time, all video shows Boltz getting a good night’s rest, often entering the den by 10 pm and not rising until after 6 am.  Rest is certainly a beneficial component for his situation.  Weather today is causing a challenge for all the wolves.  The temperatures are expected to be record breaking in the high 70’s.  This is causing Boltz and even Denali a bit more agitated with the heat.

After seeing Boltz get excited about a deer leg on Saturday night, I was hopeful that the new treatment for Myasthenia Gravis was helping. However, today he continues to have issues with back leg strength and mobility.

We will continue five more days of treatment and monitor his activity closely to assess improvement. The veterinarian has prepared me for the gravity of this condition. We have exhausted all test options for treatable conditions. All that is left are some invasive biopsies that wouldn’t yield any treatment options, only a diagnosis. The recommendation from the veterinarian is that we don’t need to put him through more painful invasive procedures while knowing there is no knowledge to be gained that would help him. Under permit from the USDA Animal Welfare Act, we are accountable for Boltz’s quality of life including what he endures during medical treatments. We will be assessing quality-of-life standards, both in his social and behavioral health, as well as his medical condition to determine what is best for Boltz

Boltz tested NORMAL for the mutated gene associated with Degenerative Myelopathy, meaning he does not have the mutation commonly known to cause the development of DM.  Our vet decided to start treating him for Myasthenia Gravis, and if that is the cause, we would expect to see improvement in a week.  Based on the extensive tests that have already been completed, the one remaining diagnosis being discussed is degenerative peripheral neuropathy which can be diagnosed by a nerve or muscle biopsy, but has no treatment.  Since this condition has no treatment, our local vets and the neurological specialists concur that this more more invasive test would not be recommended at this time.

Written by Wolf Care Assistant Leanne Martin:

Denali and Grizzer are managing quite well together. They currently share the Transition Area, East Side, and Back Habitat. Wolf care staff separate them in the morning during feeding, and once feeding is done they are put back together. One interesting observation that staff have noticed, is that Grizzer tends to follow Denali around the enclosures. Due to his age, Grizzer’s eyesight is not very good, and perhaps Grizzer is using Denali as a focal point  to move and navigate the enclosures better. Providing stimulus is important for older wolves, and Denali is certainly a great source of stimulus for Grizzer. They have not shown any aggression toward each other, and have even been able to stand near each other while getting meds through the fence.
With the arrival of snow, staff have added cover hay to various spots throughout the enclosures. Grizzer and Denali have been seen sleeping near each other in the Transition Area, an area that is completely covered by a roofline. This spot is one of the prime sleeping spots for the retiree’s due to the fact that it is completely protected from snow and ice.

Written by Wolf Care Assistant – Leanne Martin

With the arrival of 3 plus inches of new snow this week, activity in the Exhibit Pack has increased. Axel was recently observed rolling over in front of Grayson, then springing up and inviting Grayson to chase him. Grayson accepted Axel’s invitation, and chased him around the enclosure with a T-1 tail. According to the IWC’s ethogram, a T-1 tail is one where the tail is sticking up in the air, indicating confidence.
Axel and Grayson are active 4-year olds, and have plenty of energy to burn. Since the wolves are more active during winter than they are in the hot summer months, they typically consume more food to account for the extra expended energy. Since Denali’s retirement, staff have noticed an increase in Grayson’s confidence during feedings. Staff typically feed deer on Saturday nights, and beaver carcasses on Wednesday afternoons. Grayson has been confident enough to claim food, and successfully defend it from Axel.