​Social rules in the cat world: Why do cats live under the same roof but appear to be close but are actually distant?

Many cat owners have to go to work during the day and cannot accompany their kittens, so they raise one or more cats to form a multi-cat family, hoping that they can "love each other".

love&peace

However, when the cat owner was not at home, the "cat war" had already gone on for several rounds!

Cat: I’ve disliked you for a long time!

Nowadays, cats, which used to be solitary animals in nature, have long been domesticated by humans and live in groups.

As the saying goes, "love grows with time", does this apply to domestic cats?

Or, do they really regard each other as close companions because of their long-term companionship?

In July this year, a research team from Azabu University in Japan attempted to reveal how domestic cats adapt to group life by analyzing the relationship between their hormone levels, intestinal microbiomes and social behaviors.

The results are grim: Although multiple domestic cats may live under the same roof and form good relationships, they may not view each other as close companions.

The relevant research paper has been published in the scientific journal PLOS ONE.

Test your cat-to-cat relationship

In this study, 15 domestic cats (sterilized) from the same shelter in Kanagawa Prefecture, Japan participated in a two-week experiment. Among them, there were 10 male cats and 5 female cats, with an average age of 4.2 ± 2.3 years old, and they were randomly divided into 3 groups to take turns in the experiment.

During the experiment, each group of cats was housed in a fixed room at Azabu University. The room was equipped with more than 5 beds, and they were free to choose where to rest.

Additionally, there are 5 litter trays, 2 food bowls, and 2 water bowls in the room, and all cats eat the same food.

The research team used cameras and infrared lights to observe and record the cats' behavior and interactions, measure hormone levels in their urine, and collect feces to assess the types of microbes in their gut microbiome.

They hope that by studying the relationship between sociality, hormone concentrations and the gut microbiome in domestic cats, they can further understand whether the social living strategies of domestic cats are similar to those of typical social animals.

Perhaps they are similar to other social mammals and are able to form "group friend" relationships; or perhaps their inherent solitary nature leads them into conflict despite living in the same environment.

Some domestic cats are born lonely

Based on historical research on social animals, the research team proposed three hypotheses and conducted analysis based on the monitored data.

Hypothesis 1: Domestic cats with high levels of cortisol and testosterone will be less tolerant and more aggressive.

The main effect of cortisol is to increase glucose metabolism in response to behavioral responses, and it is also known as the "stress hormone." This energy production is necessary when an animal is faced with a threat, and studies have shown that individuals with higher cortisol concentrations show increased aggression or fear responses.

Testosterone is a member of the androgen family and is positively correlated with aggression. It is worth noting that cortisol and testosterone interact to regulate aggressive behavior. In this study, the research team observed a significant positive correlation between testosterone concentration and active escape behavior.

In this study, hypothesis 1 was confirmed, with negative correlations between cortisol and testosterone concentrations and contact and food sharing behaviors between cats.

Figure | Correlation between different hormones (cortisol, testosterone and oxytocin) (Source: this paper)

The data showed that cats with high cortisol and testosterone levels had less contact with other cats, and cats with high testosterone levels were more likely to try to escape. Cats with low cortisol and testosterone levels showed greater tolerance and were more adaptable to social life.

Hypothesis 2: Domestic cats with high oxytocin concentrations will display more affiliative behaviors.

Oxytocin is a peptide hormone known for its role in influencing reproductive behaviors such as mating and maternal care, and can regulate various social behaviors related to "care and defense" within the group. Therefore, the team hypothesized that if domestic cats live together as "group friends", oxytocin may induce a "nurturing" behavior between them.

However, contrary to Hypothesis 2, the results showed that cats with high oxytocin concentrations did not show the expected "sense of belonging" behavior. In this study, the team observed a negative correlation between oxytocin concentrations and close contact between cats living in the same space, and individuals with high oxytocin concentrations rarely showed interactive behaviors with out-group members.

Hypothesis 3: Frequently contacted domestic cats have similar intestinal flora and there is a relationship between the composition of the gut microbiome and hormone concentrations in cats.

The study found that the more frequent the contact between individuals, the greater the similarity of their gut microbiomes. When animals are housed together and share an environment, the similarity of their gut microbes increases due to increased opportunities for direct or indirect contact.

In addition, there are empirical studies showing that the gut microbiome can change the host's sociability by regulating oxytocin secretion in the hypothalamus, and the composition of gut microorganisms is also related to behavioral patterns and cortisol secretion.

Therefore, the research team believes that "the lower the testosterone and cortisol concentrations in domestic cats, the more they are willing to share space and live together; but the higher the oxytocin, the less affiliative behavior they have and the lonelier they are.

High oxytocin levels in domestic cats do not equate to affection, and they may not view other cats living in the same space as companions with whom they have a close relationship.”

However, this study also has some limitations.

For example, although the cats in the experiment came from the same shelter, the two-week experimental period may have been too short for them to form a close relationship.

Furthermore, the sex composition of group members is not uniform, and experiments with male-only and female-only groups may be more helpful in clarifying the adaptive significance of sex in group-living cats.

Therefore, in future work, the researchers will further deepen their understanding of domestic cat social living, such as extending the observation period from two weeks to several months, and further clarifying the causal relationship between hormones and social behavior.

Cats' thoughts: Avoid embarrassment and maintain independence

Some people believe that there is a reason why cats are not sociable.

From the perspective of animal behavior, Daniel Mills, professor of behavioral veterinary medicine at the University of Lincoln in the UK, believes that cats have evolved many mechanisms to keep their distance from other cats, such as urinating around their territory to avoid embarrassing encounters with other cats.

Even if you accidentally touch them, their hair will stand up and their claws will extend.

However, as it becomes more common for domestic cats to live in groups, scientists have discovered that cats' aversion to group living may be weakening.

In 2014, research published in the scientific journal Journal of Comparative Psychology explored the personality traits of domestic cats.

Studies show that although cats have psychotic, impulsive, and resistant personalities, domestic cats are actually much less uncooperative than wild cats.

When the researchers compared domestic cats to four other wild cat species — the Scottish wildcat, clouded leopard, snow leopard and African lion — domestic cats were most similar in overall personality to lions, which live in groups and hunt together in the wild. Compared to their ancestors, domestic cats have made some progress in "tolerating" each other's company.

In addition, domestic cats are not completely against socializing. They just have to make their own decisions when it comes to getting along with other cats and with their owners.

"To a large extent, domestic cats retain their independence and only come close to each other when necessary," said Swiss cat expert and animal behaviorist Dennis Turner.

Reference Links:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0269589

https://www.bbc.com/ukchina/simp/vert-earth-38757738