Correlations between behavior and hormone concentrations or gut microbiome imply that domestic cats (Felis silvestris catus) living in a group are not like ‘groupmates’

Abstract

Domestic cats (Felis silvestris catus) can live in high densities, although most feline species are solitary and exclusively territorial animals; it is possible that certain behavioral strategies enable this phenomenon. These behaviors are regulated by hormones and the gut microbiome, which, in turn, is influenced by domestication. Therefore, we investigated the relationships between the sociality, hormone concentrations, and gut microbiome of domestic cats by conducting three sets of experiments for each group of five cats and analyzing their behavior, hormone concentrations (cortisol, oxytocin, and testosterone), and their gut microbiomes. We observed that individuals with high cortisol and testosterone concentrations established less contact with others, and individuals with high oxytocin concentrations did not exhibit affiliative behaviors as much as expected. Additionally, the higher the frequency of contact among the individuals, the greater the similarity in gut microbiome; gut microbial composition was also related to behavioral patterns and cortisol secretion. Notably, individuals with low cortisol and testosterone concentrations were highly tolerant, making high-density living easy. Oxytocin usually functions in an affiliative manner within groups, but our results suggest that even if typically solitary and territorial animals live in high densities, their oxytocin functions are opposite to those of typically group-living animals.

Physiological Assessment of the Health and Welfare of Domestic Cats—An Exploration of Factors Affecting Urinary Cortisol and Oxytocin

“…Furthermore, because cats are solitary hunters and territorial animals [ 29 ], a visit by a researcher with handling skills may cause a stress response in the cat. One solution to these problems is to utilize physiological samples that allow noninvasive collection, such as feces [ 30 , 31 , 32 ] and urine [ 33 , 34 , 35 , 36 , 37 , 38 ]. The relationship between fecal cortisol levels and social interactions with owners in cats is not yet conclusive, as it may be influenced by factors such as the experimental environment and the cat’s personality [ 32 , 35 , 36 ].…”

“…In fact, several studies have been conducted on cats in households [ 31 , 32 , 35 ]. In addition, when urine is used, there is concern that the concentration may vary with urine volume, but this can be corrected using creatinine [ 36 , 38 ]. Although it is not possible to measure acute stress responses, it could be an advantage in assessing daily interactions between owners and cats on a daily basis.…”

“…In particular, studies have revealed that interactions between dogs and their owners increased oxytocin levels in both [ 42 , 43 , 44 , 45 , 46 ]. Some studies have quantified the oxytocin levels in the blood [ 47 ] and urine [ 36 , 38 ] of laboratory-housed cats, but not in household cats. Furthermore, in contrast to dogs, oxytocin levels in cats have been reported to increase when social interaction with their owners is restricted [ 36 ].…”