Cats have around 45-200 million scent receptors in their nose. Compare this to a human who has around 6 million, and a dog who has between 100 and 300 million. This means that a cat’s sense of smell is around 9-16 times stronger than a human’s, and often on par with a dog’s.
And like some other mammals, cats can also ‘taste’ a smell by using an organ (called a vomeronasal, or Jacobson’s organ) located between the hard palate of their mouth and the septum of the nose. When cats are super-interested in a scent, they use this organ by making a funny face (Flehmen response) which allows the pheromones to be processed by their brain.
So, why do they need such a strong sense of smell? Well, a cat’s world is all about scent. It’s often considered their primary sense, and it gives them a massive amount of information about their environment.
Often it can be hard for us humans to understand, as we depend mostly on visual and verbal signals from our environment. Though, understanding the importance of smell for cats can help us guardians keep our cats happy.
Let’s go through some of the main uses of this well-developed sense.
Cats can pick up the minute differences in scents of other cats. They use this ability to identify and recognise others from the same colony/group.
Cats in the same group tend to build up a ‘group scent’, which is a combination of all the scents of the cats who are affiliated. They do this by rubbing up against each other, allo-grooming, sleeping together, and rubbing on the same objects in the environment. This group scent is an identifier of who is in the group and who isn’t (i.e. friend or foe).
Guardians who have more than one cat may have noticed that if one cat has been absent for some time (e.g. at the vet’s), the other cats act like they don’t recognise him when he comes back home. In fact, this has actually been labelled a form of aggression (non-recognition aggression). Even though the cat coming home looks the same, he may not smell the same, which creates a recognition mismatch for the other cats who may treat him as a threat.
Keep in mind, it’s not just the identification of other cats, but also other animals and humans. Your scent is actually part of the group scent in your household! This is part of the reason cats like to hang around the lounge and bedroom – this is where your scent is the strongest!
Not only can a cat’s keen sense of smell help identify friend or foe, but is also used to identify reproductive status. Male cats can identify and locate a female in heat from a very long way away!
Cats produce and use various scents to define and ‘own’ their territory. The most obvious of these, especially for unneutered males and cats in high-stress households, is spraying.
The pheromones in spray provide a multitude of information for other cats, including gender, health status, diet, and even how long ago that cat was there. In a natural environment, cats’ territories overlap, and the information provided by spray can help them co-exist without conflict e.g. a cat who smells another cat’s marking from several hours before will know not to be at that particular place at the time the other cat was there. Basically like a system of traffic lights!
Indoor, neutered cats tend not to go to the extent of spraying to mark, but they do mark in other ways. Rubbing their face on doorways and furniture, sleeping in particular spots, and scratching, all provide ‘territorial security’ to a cat by depositing their pheromones. By being able to smell themselves on objects in their environment gives them a sense of ownership and reassurance. Periodically throughout the day they will refresh their scents on those objects to keep the scent strong.
For territorially insecure or anxious cats, applying scent through various means (e.g. scratching, spraying, facial rubbing, urinating, allo-grooming) can be a self-soothing activity.
For instance, seeing another strange cat outside can cause a cat to ramp up scent application activities, not just to define territory, but because it also reduces their anxiety. By being able to smell themselves in their territory, anxiety can be reduced. Some extra-anxious cats may even lay in their litterbox because this is where their scent in strongest!
Some guardians may notice that when their cat is stressed or territorially insecure (visitors, other cats outside etc), they may ramp up their scent refreshment activities.
Being in the middle of the food chain, cats have developed heightened senses to help them located and catch prey, and evade predators. Smell is used extensively in the pursuit of food and safety.
Not just for hunting and evasion activities, cats use smell while foraging, allowing them to identify and locate food that may be hiding. It also allows them to steer clear of potentially toxic food and water sources.
So how do we use this information to help keep our own cats happy? Here are a few ideas:
If you are the proud guardian of multiple cats, maintaining the group scent among them can help ensure a peaceful existence between them. Most often, cats will do this themselves as they would in a normal colony situation, but some households need extra help, especially if one cat tends to ‘live’ away from the others.
To do this, simply using the same brush or hand to groom them helps combine scents and deposit them on each of them. Though only do this if your cat allows and enjoys it. Forcing a cat to be brushed or rubbed can create negative associations with the scent of the others.
To avoid non-recognition aggression in a multi-cat household, if one cat has been absent for more than, say, half a day, it’s best to keep them separate for a while. A cat who has gone to the vet will have a whole host of other smells on them, including other cat’s, so separating them for several hours will give time for the smells to dissipate and the cat to apply his own smell through grooming.
Yep, here’s your excuse! Remember, cats feel secure when they can smell themselves in their environment. A cat guardian who washes all the cat bedding, their bedding, cleans the walls where the cat rubs, and vacuums the cat trees and scratching posts too regularly may inadvertently be causing some territorial insecurity! A cat who, once a week suddenly can’t smell themselves on ‘their’ objects can become anxious and spend a lot of time re-applying their scent to reduce their anxiety.
If you’ve been to a friend’s house with cats, or otherwise come in to contact with other cats, it’s a good idea to try and change before you come inside or at least go straight for a shower. Undoubtedly, your cat(s) will smell the other, strange cats on you and probably make a desperate attempt to cover you in their smell. Or worse, it can cause overt aggression.
Holidays are always a stressful time for a cat. It’s best, if at all possible, to keep them in their environment by using a pet sitter or friend to stay. Remember though, that your scent is part of the overall group scent of the household, so your absence will change this as your scent dissipates. Try and keep your scent strong so your cat maintains a sense of familiarity. This means, leave your bed sheets unwashed until you come back, leave some dirty laundry in the basket, and don’t do a big spring clean of the household before you go. Leave it nice and ‘dirty’!
I hope this article has been helpful and informative to you as a cat owner. Understanding the importance of smell and scent to your cat can help you increase your cat’s happiness, and understand why they do some of the things they do!
Here’s to happy and healthy cats.