Your Cat May Be Mirroring More Than Your Mood, Study Finds a Hormone Link

A small study in Japan suggests cats and their owners may be linked in a measurable biological way. Researchers found that owners with higher oxytocin often had cats with higher oxytocin too, though the work does not show exactly why that pattern appears.

A bond that showed up in hormone readings

The research focused on two hormones often discussed in studies of bonding and stress. Oxytocin is involved in social bonding and can increase during affectionate contact. Cortisol helps regulate the body's stress response and energy use.

In this study, higher oxytocin in owners tended to line up with higher oxytocin in their cats. Researchers also found that cats with higher oxytocin were linked to owners who reported fewer negative emotions and had lower cortisol.

The owner mood findings were specific. People living with cats that had higher oxytocin reported less anger, confusion, anxiety, and depressed mood. But there was an important complication in the dataset: some people had more than one cat. When the researchers grouped results by household to account for that, only the links involving confusion and anxiety still held up statistically.

The study also picked up another connection related to proximity. Cats wore small Bluetooth beacons on their collars, and the signals sent to owners' phones were used to estimate how near they were to each other at home. Owners who were generally closer to their cats reported more energy and vigor. By contrast, the number of years a person had lived with a cat was not associated with that score.

How the study was done

The team, led by Saho Takagi of Kyoto University, recruited 19 owners and 29 pet cats. For the hormone comparison, the researchers used data from 24 cats whose urine could be collected and their 17 owners.

Rather than relying on a single reading, the team averaged measurements from three urine samples for each individual. Owners also completed a questionnaire about how they had been feeling over the previous few weeks.

The researchers said no earlier study had measured oxytocin in both cats and their owners. That made this project a first look at whether a biological pattern might be visible on both sides of the relationship.

Takagi suggested petting as one possible explanation for the oxytocin link. She said the hormone may rise in both the owner and the cat through the interaction of petting and being petted, and that this interaction may help form their bond.

The study included one additional behavioral test. In that exploratory part of the work, cats with higher oxytocin were more likely to approach a person sitting inside a marked circle. That person could be the cat's owner or a stranger.

What the findings can and cannot say

The results are intriguing, but the researchers were careful not to overstate them. Hormone readings are not direct measurements of happiness or stress. Oxytocin has roles beyond social bonding, including childbirth and milk release, and a higher level does not automatically mean a stronger relationship. Cortisol also changes naturally over the course of a day.

The study did not find a clear association between cats' cortisol and owners' cortisol. The researchers noted that this may have been harder to detect because the sampling methods differed. Human urine was collected in the morning, while cat samples were collected whenever possible. They also pointed out that a 2019 study in dogs had found a cortisol connection, but that work used different methods.

Just as important, the oxytocin result does not show hormones rising and falling together in real time. The team compared average concentrations, not moment-to-moment changes. Takagi said that to call the pattern true synchrony, hormones would need to be measured at multiple time points and shown to change in a similar way over time.

The Bluetooth data had limits as well. The devices could estimate closeness, but they could not show what the cat and owner were actually doing. A cat sleeping beside a person and a cat being stroked could produce similar signals.

The project also cannot establish cause and effect. The month-long study does not prove that cats lowered their owners' stress. It is also possible that people who were already feeling better interacted more with their cats. Takagi said that testing hormones before and after petting would be one way to investigate causality.

Other caveats remain. The study was small, 16 of the 19 owners were women, and the exploratory analyses were not preregistered. Even so, the work adds a new layer to a familiar question. Many cat owners already feel that life with a cat affects them deeply. This study suggests that connection may be visible not only in behavior, but also in biology.