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Can a dog sense if another dog is sick?

Can a dog sense if another dog is sick?

Dogs have an incredible sense of smell and can be trained to sniff out illnesses in humans and in other dogs. It seems reasonable then to think that dogs know when another dog is sick.

Can a dog sense if another dog is sick?

A dog’s sense of smell is 100 times better than ours, and they are able to detect the slightest change around them. It is not so much that they smell the illness itself, but they detect changes that are subtle. 

Most research has gone into dogs detecting illness in humans, but it would seem reasonable that if they can detect minute changes in humans, they should also be able to detect those changes in their fellow canines. 

Dogs are also able to pick up on visual clues that we may miss. They can tell when a human, or another dog, is feeling bad, whether physically or from depression. They are also experts at reading body language.

With the incredible sense of smell, dogs are able to detect the slightest change. Research continues into trying to figure out exactly what they are smelling, but the fact that they can notice the slightest change is well established.

A dog might smell a change in another dog that turns out to be a tumor. The dog doesn’t know what a tumor is, but they know there is something in a specific area that is different and that is causing the other animal pain or distress.  The dog may spend a lot of time sniffing at the specific area where the tumor is or licking that area on another dog.  When a dog notices another dog has some kind of change, they will follow that dog around more, or stare at the dog more with a tilted head. 

Dogs often lick their own wounds. A dog may also then try to lick another dog’s wounds for the same reasons. This could be a visible wound or just the area where the other dog is hurting.

If you see your dog paying more attention to a specific area on another dog’s body, that could be a sign something is wrong. It is a good idea to talk to your vet about this. Dogs can detect an issue early, and often that can save another dog’s life.

Some signs your dog is detecting something is wrong with another dog:

  • Excessive staring
  • Whining
  • Paw raised, touching the other dog.
  • Licking
  • Sniffing the area in question
  • Cuddling up to the other dog
  • Putting its head on the other dog.

Can dogs detect cancer in other dogs?

The short answer to this is yes. Dogs have been trained to detect cancer in humans, and they can do the same with other dogs. Dogs are trained to use their noses in many ways. Police train dogs to sniff for drugs, or human bodies, from a young age.

What exactly the dog is smelling is unknown, but the dog can be trained to sniff out the slightest difference between the two items. Part of the training involves letting the dog smell blood samples from cancer patients and then letting them smell the blood that is not cancerous. This is how dogs can be trained to smell for almost any kind of substance.

A dog can tell the difference. When the dog smells patience, it can signify they have found the smell they have been exposed to.  It is the same way they find drugs hidden in people or places.

Even dogs that have not been trained can detect if something is different or has changed, no matter how small the change. Dogs have been trained to find skin cancer by sniffing people and spotting any area that is different from another area. It may or may not be cancer, but they have found something that is different and can point to exactly where it is.

If you have more than one dog, it is a good idea to pay careful attention to how they act around each other. If something changes, there is most often a reason for that change. If one starts paying more attention to a specific spot on another dog, that could be an indication they are smelling something that is different or something that has changed. If this behavior continues, it is something that should be checked out.

If you see a change like this, even if the other dog seems fine, there could be a serious health issue lurking under the surface. One dog could smell cancer in the other dog, or a tumor. If these are caught early enough, they can be treated relatively easily, and it will save the other dog’s life.

If your dog seems subdued or depressed around the other dog or whining, that could be an indication your dog is picking up on stress or pain in the other dog. Watching your dog’s interaction can be very valuable in giving a warning signal that something is wrong well before the problem is visible.

Research continues into dogs detecting illnesses like cancer in other dogs. Veterinarians are not yet ready to have a dog on staff to scan other dogs, but research is mounting that shows dogs can indeed pick up on cancerous cells with their noses.


There is ongoing research in Finland that is exploring whether dogs can sniff out the Covid-19 virus in humans. So far, the research has shown positive results. Dogs have been able to tell the difference in urine samples of patients with and without the virus.

Scientists are still trying to determine if COvid-19 creates a specific smell in the blood, which would make a difference. Dogs are able to tell the difference in urine samples, but there is still more research to be done before definitive answers are given.

Can dogs tell when another dog is hurt?

Yes, dogs can tell when another dog is hurt. Often it is obvious because the hurt dog is yelping or whining. But they are also able to tell when it is not so obvious. Your dog could have an injury of some kind, and be in pain, and you might not be aware of the dog’s discomfort.

A hurt dog may be more lethargic, lie around more, not be interested in doing normal things.  A big change in a dog’s behavior like that is an indication something is wrong. If you have another dog, and the other dog may be able to give you some clues as to what is wrong with the lethargic dog. That information could be invaluable to a veterinarian trying to treat your dog.

Dogs have 300 million olfactory sensors in their noses, while humans have around six million. That is how much greater the sense of smell is for dogs. Further, about 40 percent of a dog’s brain is involved in interpreting those smells. So their ability to smell is nothing short of incredible. What makes it even more remarkable is the amount of brain space they have devoted to what those olfactory receptors are receiving.

There is also a small organ inside a dog’s nose called a vomeronasal organ, that can detect pheromones, which are produced by all species of mammals. These pheromones relate to information about emotions and mating. In theory, at least, dogs can even smell emotions.

When a dog knows another dog is hurting, they will sniff that area, lick it, paw at it, or push on the area with their noses.

Can dogs sense distress in other dogs?

Dogs can smell when something is different and, to some extent, can smell emotions. They may not know what the emotion is, but they can tell if it is a good or bad one by smell. Scientists are not starting to believe dogs can also interpret facial expressions in humans and can tell if a person is happy or sad even from pictures. It would stand to reason then, that dogs can detect the same thing within their own species.

Researchers say it is impossible to know if dogs realize another dog is dying, or even if they are dying themselves. They may or may not understand their fellow dog has died, but they do know the other dog is no longer there, and they may exhibit signs of missing them.

Dogs can get depressed when their companion dies, and grieve just like humans do. Their actions are similar to the actions of depressed people.

  • Act depressed or listless
  • Decreased appetite
  • Not want to play or do normal activities
  • Lethargic or sleeping a lot

Just as dogs can tell when a companion dog is sick, they can also tell when their companion is in distress. They would know, for instance, if another dog has his paw stuck in a fence and might try to help. That could backfire though, as the distressed dog may blame the other dog or think the other dog is causing the problem.

Will dogs avoid a sick dog?

Ordinarily, dogs will not avoid another sick dog.  If a dog is sick, or distressed, he may try to avoid contact with other dogs or humans and want to be off by himself.

When your dog knows another dog is sick or hurt, they may actually try to be closer to the sick dog. They may follow them around more. Your dog may actually pay more attention than usual to a sick dog, staring at it, whining, or trying to lick the area that is hurting the other dog.

Going back to times when dogs were wild animals, they instinctively tried to hide from predators. When they are sick, they may realize their capacity to escape is limited, so they will seek out a hiding place. They look for a place where they will be safe from predators.  It is not so much the healthy dog avoiding the sick one, but the sick one trying to get away from everything. Of course, dogs are not in danger from predators while in a modern home, but it is the wild instincts that come out when they are in distress or sickness.

Do dogs have empathy?

It is clear that dogs have empathy when their humans are sick or suffering.  There is some research that suggests dogs have empathy for other dogs that they live with. Dogs that had lived together for more than a year were tested by playing sounds of the other dog making distressed whines or other signs of distress. Researchers found more reactions to the sound of the other dog than to regular sounds. 

It seems that dogs are able to tell the sounds of their companions apart from the sounds of other dogs. The research also found more reactions from the dogs when their companion was showing signs of distress. When reunited in the study, the dog showed concern for its companion dog.