Why do domestic cats carry out ‘scent exchange’ with their owner? First of all, what is scent exchange? It may not be apparent to a cat caregiver that it is taking place. However, it happens very often, particularly when a cat owner comes home and their cat greets them. The cat will do one of three things: she may rub up against their owner’s legs, hop up on their hind legs or roll over onto their back. The tail will be erect to signal friendship.
When a cat rubs up against your legs, they start by pressing the side of their face against the person’s leg. The cat will then lean in slightly and rub the side of their body all along one of their flanks. Finally, the cat may twine their tail around the vertical leg of their caregiver. He or she may then look up and vocalise a greeting and then repeat the process. They will certainly do it more than once, if possible.
And if the caregiver reaches down the cat will quite possibly head-butt their hand. Although the head-butt is meant to be head-to-head, the human is far too tall for that and therefore the hand is a substitute. Or a cat may push the side of their mouth against the hand. When the greeting ritual is complete the cat may be fed a treat by their owner (as another ritual) or the cat might sit down and groom himself.
The whole performance has a meaning and what the cat is doing is carrying out an involved scent-exchange process between their owner and themselves. Those apparently uncontrolled rubbings against their owner’s leg are very controlled and precise.
Cats have glands all over their body including on their face, temples and cheeks, ear flaps (pinnae) and the base of the tail. And so, without their owner being aware, their cat is deposited their scent onto them. People can’t smell this feline scent but for a cat the smell is very apparent and important.
The whole process is geared up to making the cat feel more at home. This is important because they are living in a human environment with giants. They need to constantly reassure themselves. Of course, the scent of their human caregiver is automatically deposited onto them at the same time.
In depositing their scent onto their human friend and their human friend depositing their scent on them they are merging themselves with their human caregiver. I see this as a bit like a cement binding the two species together. They both take a bit of each other and therefore become a little bit more like each other. This makes the enormous interspecies difference less obvious and the friendship is enhanced.
If a cat sits down afterwards and lick themselves, they lick off some of this scent and in doing so they taste it. In this way they are able to read the human scent signals.
An alternative greeting, which is sometimes displayed by a cat, is to roll over and go belly up. This is an expression of trust and therefore also an expression of friendship.