Dogs can sniff out various illnesses, including cancers (lung, breast, prostate, colorectal), infections (COVID-19, malaria, bacterial), and metabolic/neurological conditions like diabetes (blood sugar changes), epileptic seizures, and migraines, by detecting specific volatile organic compounds (VOCs) released by diseases, often through breath, sweat, or urine samples, acting as early, non-invasive diagnostic tools.
In addition to cancer, some dogs are being trained to recognize signs of the following five conditions.
The short answer is yes, dogs can smell illness. Their sense of smell a thousand times more sensitive than ours. Many dogs are being trained to smell out cancers and pre diabetic problems and prodrome seizures.
Illness results in chemical changes in the body and changes in hormones and these changes can be detected by the dog's extraordinary sense of smell.”
There is anecdotal evidence that dogs can also sense death, but how they process and perceive this information is still being debated and researched. Dogs have a strong sense of smell that allows them to pick up on changes that can happen to a body.
They Can Smell It
So, if your body changes your scent will too, so that's usually how dogs can tell if you're sick, or even pregnant. Your mood can even change how you smell as well! Some dogs are even trained to become alert dogs because of this incredible sniffing ability.
An hour for a dog feels much longer than an hour for a human because dogs perceive time more slowly due to their faster metabolism and heightened awareness of routines, so a 10-minute wait can feel like 70 minutes to them, and your hour-long absence feels like an eternity, though they don't grasp clock time but rather the intervals between events like meals, walks, and your return.
Changes in Behavior and Body Language:
They may become more attentive, gentle, or protective towards their sick owners. Many pet owners have reported their dogs refusing to leave their side when they are unwell, providing comfort and support during times of illness.
The 3-3-3 rule is a roadmap for the first three days, three weeks, and three months after pet adoption. It emphasizes patience, consistency, and positive reinforcement to help pets acclimate to their new environment.
Is sniffing good for dogs? Yes! Sniffing is hugely beneficial for dogs and essential for their wellbeing. It's stimulating too - experts tell us just 20 minutes of sniffing is equivalent to an hour's walk in terms of enrichment for your dog.
"Silent killer" in dogs usually refers to deadly diseases that progress with few early symptoms, primarily Heartworm, Hemangiosarcoma (a type of cancer), and sometimes Leptospirosis or Canine Parvovirus, all characterized by vague initial signs, rapid progression, and severe organ damage, making prevention and early detection crucial.
It's all in the eyes.
When it comes to understanding what's on your dog's mind, the eyes are your go-to. Ever noticed your pup's eyes widening more than usual? That could signal stress, fear, or even aggression. On the flip side, squinty eyes might point toward discomfort.
Dogs use their sense of smell to navigate and understand their surroundings. If there have been changes in your home, such as the introduction of new furniture, renovations, or the presence of unfamiliar scents, your dog may be sniffing you more to gather information and adapt to the changes.
Dogs are possibly the most well-known example of an animal that can detect a range of diseases – including Parkinson's disease, bladder cancer and malaria. Epileptic seizures and low blood sugar in diabetic patients can also be detected by specially-trained medical alert dogs.
Dogs can also be trained to identify areas contaminated with dangerous substances such as toluene [113]. They can detect these substances in very small amounts (0.1 g) and over long distances, where conventional equipment fails.
It's All About the Smell
Over time, these can produce odors that are intriguing to your dog. To your pup, your belly button might smell like a concentrated version of you—a scent they find comforting and familiar. This natural curiosity about scents often leads to sniffing and licking behaviors.
The most commonly surrendered dog type is the "pit bull type" (including mixes), often due to negative stereotypes, breed-specific legislation, and high energy levels, followed by other popular breeds like German Shepherds, Huskies, and Labrador Retrievers that may not fit owner lifestyles. Breeds like Staffordshire Bull Terriers (especially mixes) also top surrender lists in some regions like Australia.
Place the back of your hand on the pavement. If you can't keep it there for five seconds, it's too hot to walk your dog. If you didn't know about this rule, chances are your friends don't, either.
The time it takes for a dog to adjust to a new home can vary from one dog to another. Normally, it takes 2-3 weeks for a dog to adjust to a new home, but it can take up to 3 months for them to fully adjust behaviourally.
Dogs can tell when someone is sick. They can also tell your emotions. If they know something is wrong then they will stick tight by your side until you're ok.
Since this event, it has been observed that dogs can smell a range of cancer subtypes, as well as a range of other diseases, including malaria, Parkinson's disease, and epilepsy (2–5). The most likely explanation is that the olfactory receptors of dogs are detecting volatile organic compounds (VOCs).
How do they do this? It's biological. All animals have circadian rhythms - physical, mental, and behavioral changes that follow a 24-hour cycle, responding to light and darkness in the environment. They may also be affected by factors like temperature and social cues.
Harvard psyhologists reveal that dogs dream of their humans
What you may not have realised however is, according to new research by Harvard psychologists, your dog is likely to be dreaming about you too – their human – the most important thing in their life.
Given that dogs can remember us and read the cues, then yes, they most likely know when we are going away, although, not for how long.