Dogs are known for their incredible senses and strong emotional connections, especially with other dogs. Many dog owners notice that when one dog in the household is unwell, the others often act differently — becoming quiet, protective, or even anxious.
These changes lead to the question: do dogs know when a dog is sick?
Do Dogs Know When a Dog Is Sick?
Dogs can often sense illness in other dogs due to their powerful sense of smell, keen observation skills, and ability to pick up on emotional cues. Their noses can detect chemical changes in a sick dog’s body, while their behavior reading skills allow them to notice weakness or distress.
Also, dogs are pack animals, so they are naturally tuned in to the health and behavior of their companions.
This combination of instincts and senses explains why many owners report that one dog acts differently when another in the household isn’t feeling well.
How Dogs Know When a Dog Is Sick
1. Heightened Sense of Smell
A dog’s nose is up to 100,000 times more powerful than a human’s. When another dog is sick, subtle changes in hormones, pheromones, and body chemistry occur. These changes are often released through breath, saliva, or even skin.
Healthy dogs may pick up on these scents and react with increased curiosity, concern, or even avoidance, depending on the illness.
2. Behavioral Observation
Dogs are experts at reading body language. If another dog is moving slowly, refusing food, or showing discomfort, the observing dog may notice and adjust its behavior.
For example, a normally playful dog may stop initiating games with a sick companion or may become calmer around them, recognizing that their energy is low.
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3. Emotional Empathy
Many dogs form deep bonds with their canine siblings or housemates. When one dog is unwell, the other may display signs of stress or empathy.
This can include pacing, whining, staying close to the sick dog, or even grooming them. These actions show that dogs are not only aware of the illness but may also try to comfort their friend.
4. Protective Instincts
As pack animals, dogs often take on roles within their group. If one dog appears weak or vulnerable, another might step into a protective role.
This can look like standing near the sick dog, becoming more alert to noises, or discouraging other animals from approaching.
This instinct is rooted in survival, ensuring that weaker members of the pack are safeguarded.
5. Changes in Routine
Dogs thrive on routine. When one dog in the household becomes ill, daily activities such as walks, feeding, or playtime may be disrupted.
Healthy dogs quickly notice these changes and may associate them with their sick companion. This awareness can reinforce their sense that something is wrong.
6. Learned Experience
In multi-dog households, dogs often learn from past experiences. If they have previously seen a dog recover from illness or witnessed trips to the vet, they may begin to associate certain signs or behaviors with sickness.
Over time, this recognition strengthens their ability to “know” when another dog is unwell.
What to Do If Your Dog Is Noticing Another Dog’s Illness
If you see that your healthy dog is acting differently around a sick dog, it’s important to pay attention.
Encourage gentle interactions, such as resting together or offering comfort, but also make sure your healthy dog isn’t overwhelming the unwell one.
Provide quiet spaces where the sick dog can rest undisturbed while ensuring the healthy dog still receives enough attention and exercise.
Keeping routines as stable as possible will help reduce stress for both dogs.
You can also monitor their interactions closely. Sometimes, dogs may act overly protective or even anxious when they sense illness. If this creates tension, consider giving them supervised time apart until the sick dog recovers.
Always prioritize the comfort and safety of the unwell pet while supporting the emotional needs of the healthy one.
When to Call or Visit Your Vet
If one of your dogs is showing signs of illness — such as vomiting, diarrhea, coughing, lethargy, or refusing food — you should contact your veterinarian promptly. Even if the healthy dog’s behavior is what alerted you, it’s best not to wait until symptoms worsen.
You should seek urgent veterinary attention if your sick dog shows severe symptoms like difficulty breathing, collapsing, pooping blood, or persistent vomiting.
Also, if your healthy dog begins to display stress-related behaviors (such as refusing to eat, excessive whining, or aggression), speak to your vet for guidance on managing both dogs’ well-being.
Read more: Dog Diarrhea and Not Eating (What you should know)
Key Takeaway
Dogs are remarkably perceptive creatures. Through their sense of smell, body language reading, and emotional bonds, they can often detect when another dog is sick.
If your dog seems unusually attentive, protective, or anxious around their companion, it may be a sign that something is wrong.
Trust both your instincts and your dogs’. Seek veterinary help whenever illness is suspected, and provide comfort and stability to both pets.
By paying attention to these signals, you can ensure your dogs feel supported, safe, and cared for when one of them isn’t at their best.