Getting on: Hormones and microbiomes influence cat sociability


By Dr. Tim Sandle
Published July 28, 2022

Domesticated cats and their bigger cousins in the wild are highly prone to genetic kidney problems - Copyright AFP Amir MAKAR

Why do some cats live (mostly) content in the same community or household whereas other cats will not tolerate any other cat at all? For cats that can cohabit, why is this behaviour relatively rare among other feline species? The answers to these questions rests with a mix of hormones and microbiomes.

Researchers from Azabu University in Kanagawa, Japan, have been examining links between hormones, gut microbes, and social behaviour in cohabitating cats, attempting to figure out why some of these solitary animals live in high densities.

The researchers conducted a two-week-long study of three different groups of five cats living together in a shelter. To gather data, the researchers used video cameras to observe the cats’ behaviour. In addition, they measured hormone levels in their urine, and collected faeces to evaluate the mix of microbial species in the cats’ microbiomes. The microbiome is the community of microorganisms together with the genetic interactions.

The outcome of the data review showed cats with high levels of the hormones cortisol and testosterone had less contact with other cats. Plus, cats with high testosterone (a sex hormone belonging to the androgen family, is positively correlated with aggression) were more likely to try to escape. In contrast, cats with low cortisol and testosterone were far more tolerant in their interactions with other cats.

Cats with high levels of the hormone oxytocin did not display bonding behaviours described as “socially affiliative.” This contrasts with the presence of this hormone with other animals that do bond, indicating that oxytocin functions differently for solitary animals living in groups.

As well as hormonal differences, the researchers discovered a greater similarity of gut microbiomes between cats who had more frequent contact with each other. Plus, there was a connection between the gut microbiome, social behaviour, and cortisol levels. Changes in food resource niches can modulate gut microbiome.

It is highly probable that the gut microbes influence hormone secretions and behaviour mechanisms of individuals.

According to lead researcher Hikari Koyasu: “Low testosterone and cortisol concentrations in cats enabled them to share the space and live together, but the higher the oxytocin, the less affiliative behaviour with others and the more lonely they are. The function of oxytocin was different from that of affinity for a group-mate. Cats may not consider other individuals living in the same space as tight relationship group-mates.”

The research appears in the journal PLOS ONE, titled “Correlations between behavior and hormone concentrations or gut microbiome imply that domestic cats (Felis silvestris catus) living in a group are not like ‘groupmates’”.