Cats' vocalisations when interacting with people may be a signal directed at someone who can resolve their dissatisfaction, a study suggests.

On Nov. 12, local time, online media outlet Gigazine reported that researchers at the University of Sao Paulo in Brazil confirmed in an experiment involving 38 cats and their owners that cats' crying frequency and total number of cries increased markedly when a person was present.

Cats have been known to cry louder and more often in front of people than in front of other cats. Observations that stray cats cry less than house cats have also led to the view that distance from humans may be linked to crying, but the purpose of the crying has not been clear.

The researchers noted that all cats in the experiment tended to cry often when food was involved. They prepared a small plastic box containing a favourite treat. The box had holes so the cats could tell there was a treat inside, but opening it required human force, meaning the cats could not solve it on their own.

The experiment was conducted under 2 conditions. In one condition, a person stayed in the same space and paid attention to the cat. In the other, the person left the room. The researchers observed the cats' crying frequency and behaviour for 1 minute under each condition.

The results were clear. When no person was in the room, the total number of cries was 20. When a person was present, it rose to 86.

Behaviour patterns also differed. When crying, the cats looked at the person or alternated their gaze between the person and the plastic box. By contrast, when no person was present, they stared at the room's door for longer. This suggests the cats may not have merely expressed dissatisfaction at being unable to eat the treat, but responded toward a target that could change the situation.

The researchers said they did not overinterpret the results. They said the experiment alone could not determine whether the cats understood that a person could solve the problem, or whether they were intentionally asking for it to be resolved. Even so, it was confirmed that crying may not be just an expression of frustration.

The study also has limits in its subjects. The cats that participated were selected because they already tended to cry often in food situations. Because of this trait, further verification is needed to see whether the same results would appear in cats with different tendencies.

Accordingly, follow-up research is expected to continue by comparing cat crying across various situations other than food to see whether cats distinguish and use vocalisations according to intent. The study showed that animals living with people may express themselves in a more goal-oriented way than previously thought.