Cortisol levels in hair provide a long-term marker of stress, making them a useful tool to explore how human–animal relationships may affect shared physiology. Wojtaś et al. (2022) examined whether owners and their dogs and cats, all living in the same household, showed correlated stress levels.
The study involved 25 women, each owning at least one dog and one cat, with a total of 45 dogs and 55 cats included. Researchers collected hair samples from both owners and pets and compared cortisol concentrations. Overall, no significant general correlation was found between owners and their pets or between cohabiting dogs and cats.
However, specific interaction patterns did matter. A significant positive correlation between owner and dog cortisol appeared when owners groomed their dogs once a week. Similarly, for cats, cortisol correlations emerged when owners reported never kissing their cats, suggesting that the nature and frequency of human–pet contact can influence shared stress markers.
These findings highlight that while overall cortisol synchronization was not widespread, grooming and bonding practices may shape subtle physiological parallels between humans and their pets. The results suggest that the emotional ties within multi-pet households are complex, context-dependent, and shaped by daily care routines and expressions of affection.
Source: Wojtaś, J., Garbiec, A., Karpiński, M., Skowronek, P., & Strachecka, A. (2022). Are Hair Cortisol Levels of Humans, Cats, and Dogs from the Same Household Correlated? Animals, 12. Published June 1, 2022.
