When your cat comes running up to you with their tail in the air, it’s a wonderful feeling. But how do cats recognize their humans? Well, one way may be through their sense of smell!
A cat’s sense of smell is far better than human’s, thanks largely to the fact they have many more olfactory receptors (smell receptors). In fact, they use scent to gather social information in the same way that we use faces and voices.
Every one of us carries a unique mix of skin oils, sweat, breath and the scents of places we’ve been. Cats learn these complex signatures, using them to perceive humans and identify if we’re calm or stressed.
A recent study even found that cats could distinguish their humans by scent, with cats spending less time sniffing their cat parent’s scent than that of a stranger’s. The study also found that cats often sniffed familiar scents with their left nostril and unfamiliar human scents with their right.
When cats rub, knead or groom, they’re not just being affectionate. They’re actually demonstrating a behaviour called “scent mixing”, in which they build a “group scent”. This allows cats to recognize humans, especially their humans, as well as their environments.
Cats have scent glands along their cheeks, foreheads, lips and bodies—especially near the tail. When cats rub against humans or objects, they use these glands to actively spread their scent and pheromones to mark their territory.
Often, when a cat rubs against a human or piece of furniture—or any items like bedding and soft clothes—they are mingling scents. This helps cats recognize familiar individuals and environments, establish social bonds, and feel comfortable within their home.
Scent-swapping can be a great way to introduce new cats to a household, familiarizing them with different smells before visiting new people or places and leading to smoother introductions.
Kneading (also known as making biscuits!) originates from kittenhood, when kittens often knead their mother’s belly to stimulate milk flow.
As adults, some cats still knead when they feel safe and content. The kneading motion activates scent glands in their paw pads, letting them deposit their scent and—when used on humans—marking those humans as familiar and safe.
Cats who share a space often groom each other. This is another way of mixing their scents and strengthening their sense of belonging. Some cats may try to groom their humans too, through licking or gentle nibbling.
Like many animals, cats use scent to mark their territory and create invisible signposts to define the boundaries of their domain. They do this by rubbing against people and objects, subtly spreading their scent and pheromones around their space.
If multiple cats live in one territory, conflicts may occur, leading to more distinctive territory marking methods like indoor urine spraying or scratch marking.
When your cats are out roaming, they may not have a GPS system, but they can build their own scent map. By marking their way with scent deposits, they can note safe or unsafe locations where they can find food, water, hiding places and more.
Cats depend on their sense of smell to identify when food is safe to eat, especially when stalking potential prey. You’ll find that many cats with an impaired sense of smell may refuse food when they can’t detect its aroma.
Cats view the world through a different lens to humans, which naturally means cats perceive humans differently to how we view them in return. Still, cats know that humans are not cats: we’re too big, smell different and act strangely! However, we are a part of their social group, and cats can recognize and incorporate humans into their environment through scent-mixing.
Like us, cats can be confused and distressed by sudden scent or environmental changes. Strange or strong new scents—from things like cleaning agents, freshly painted surfaces, or unfamiliar perfumes—can confuse cats, completely shifting their scent map.
In a group or cat colony, if one cat’s smell changes—say after a vet visit—others may not immediately recognize it, leading to conflict.
When there are significant scent changes, you may find that your cat:
It’s not in your head, your cats can recognize how humans are feeling!
It’s widely known that when we feel stressed, anxious or fearful, our bodies release different hormones—like cortisol or adrenaline. These hormones can shift the chemicals in our sweat and breath and subtly alert our cats to our shifting mood.
A study published in 2023 proved that cats displayed more stress-related behaviour when sniffing odours from fearful humans compared to that of a neutral odour. Curiously, these cats tended to use their right nostril more for these “fear” odours.
But it’s not just a cat’s sense of smell that tips our kitties off. Cats recognize their humans’ behaviours and know when our moods shift: we may move more sharply, speak differently or interact with them less.
Here are just a few ideas of how to help your cats cope with new smell changes:
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