The bond between a cat and its owner may also be reflected in their hormones.
When a cat settles down beside us, its presence can sometimes have a calming effect. But is that merely an impression? Japanese researchers wanted to understand what happens in the bodies of cats and their owners during everyday life.
The team from Kyoto and Azabu universities followed 29 cats and their 19 owners for a month. The researchers collected urine samples to measure two hormones: oxytocin, notably associated with social bonds, and cortisol, often linked to stress. They also asked the owners about their moods.
To determine how long the animals stayed near the humans, small Bluetooth tags were attached to the cats' collars. This allowed the scientists to estimate their proximity throughout the day, without asking the owners to record every moment they spent together.
The hormonal analyses, conducted in particular using samples from 24 cats, revealed an interesting relationship. In general, the higher the amount of oxytocin measured in an owner, the higher it was in their cat as well. This does not mean that their hormones rose and fell at exactly the same time: the study mainly shows a statistical link between their levels.
Another finding was that owners of cats with higher oxytocin levels tended to report fewer negative emotions and to have lower cortisol levels. By contrast, the cortisol levels of the cat and its owner did not appear to change together in any clear way.
The researchers also observed that people who spent more time near their cat generally said they felt more energetic. The length of time they had lived together was not associated with positive mood in the same way. Frequently being near one's pet might therefore matter more than the number of years spent with them.
Should we conclude that cats necessarily make their owners happier? No. The study was small, and the researchers did not ask participants to change their habits to test for an effect. It is possible that people who are already more relaxed seek their cat's company more often, or that their shared environment influences both of them.
These observations nevertheless provide a new clue about the bonds that form between humans and animals. Scientists now want to understand whether proximity and interactions genuinely affect hormones, in which direction, and under what circumstances.