Dogs have an extraordinary sense of smell that far surpasses our own. With over 300 million olfactory receptors, compared to our measly 5 million, dogs can detect scents that are entirely undetectable to humans. Their noses are finely tuned instruments, capable of sniffing out everything from changes in body chemistry to environmental shifts that we could never imagine.
Here are just a few of the things that dogs can smell:
**The smell of fear and stress.** You might think your poker face is flawless, but to a dog, your body is an open book. Dogs can smell changes in your hormones, particularly cortisol and adrenaline, which are released when you’re feeling stressed or afraid. When you’re nervous, your body produces more sweat and releases these hormones, which your dog’s sensitive nose can pick up almost instantly. This ability is why dogs often react differently when someone is anxious or scared, either becoming more protective or more cautious themselves. Their noses clue them into emotions that humans can’t easily perceive, making them empathetic companions.
**Illnesses like cancer and diabetes.** Dogs have been trained to detect serious illnesses like cancer and diabetes with incredible accuracy. Certain types of cancer, such as lung and ovarian cancer, release volatile organic compounds that dogs can smell in a person’s breath or urine, often before any clinical signs are present. Similarly, dogs can detect changes in blood sugar levels, making them life-saving companions for people with diabetes. These dogs are even known to alert their owners before a hypoglycemic episode occurs. The medical world is increasingly recognizing the potential of using dogs in diagnostic settings because their noses can quite literally save lives.
**Oncoming seizures.** Another incredible ability some dogs possess is detecting oncoming seizures in individuals with epilepsy. Although it’s not entirely understood how they do it, it’s believed that dogs can sense subtle changes in a person’s body chemistry before a seizure begins. These changes could be related to the release of specific scents or a shift in the electrical activity of the person’s body. Seizure-alert dogs are trained to give their owners warnings—such as pawing, barking, or lying on them—to ensure they’re in a safe place before the seizure strikes. It’s a remarkable skill that continues to baffle scientists and save lives.
**Low blood sugar levels.** For people with diabetes, a drop in blood sugar levels can be life-threatening, but some dogs can sniff out this change before it becomes dangerous. When blood sugar levels drop, the body starts releasing ketones, which have a distinct smell that dogs can detect. Diabetic alert dogs are trained to recognize this scent and alert their owners so they can take action. This isn’t just a convenient skill; it can be a life-saving one. Thanks to their extraordinary sense of smell, these dogs provide an added layer of security and reassurance to their human companions.
**Changes in the weather.** Ever noticed your dog acting strangely before a thunderstorm or major weather shift? Dogs can detect changes in atmospheric pressure and the smell of ozone that often comes with a storm. Their keen senses allow them to pick up on these environmental changes long before we do. Dogs may become restless, hide, or bark excessively as a storm approaches, reacting to cues that are imperceptible to humans. It’s like having a furry weather forecaster in your home—one that’s far more reliable than your smartphone’s weather app. Their ability to sense incoming weather changes has been honed over thousands of years.
**Pregnancy.** Dogs are known to become more protective and affectionate toward pregnant women, and this is because they can smell the hormonal changes that occur during pregnancy. A pregnant woman’s body releases a cocktail of hormones, including progesterone, estrogen, and human chorionic gonadotropin, which dogs can easily detect. They may start to follow the pregnant woman around, rest their head on her belly, or display protective behaviors. This ability to detect pregnancy highlights how dogs are deeply attuned to the biological signals of the humans they love. To them, a pregnant woman smells different, and they respond with gentle curiosity and care.
**The passage of time.** Believe it or not, dogs can smell time. They use their sense of smell to understand how time passes, picking up on the scents that change throughout the day. For instance, in the morning, the scent of breakfast lingers in the air, while in the evening, it may be dinner smells or the scent of a loved one returning home from work. Dogs are excellent at associating specific scents with routines, which is why they seem to know when it’s time for a walk or when a family member is about to come home. It’s as if they have an internal olfactory clock.
**Diseases in plants.** Dogs aren’t just good at detecting illnesses in humans; they can also sniff out diseases in plants. Certain diseases cause plants to release unique chemical compounds that dogs can detect. Agricultural researchers have been working with trained dogs to identify citrus greening disease in trees, a devastating illness affecting citrus crops worldwide. By sniffing out the disease early, farmers can take action to prevent the spread and save their crops. It’s a fascinating example of how dogs’ powerful sense of smell can be used in agriculture to detect problems long before humans ever would.
**Bed bugs and
