Cats may look inscrutable, but they actually have almost 300 different facial expressions which they show to each other.
Felines are not as hostile as they sometimes seem either, with the majority of their facial expressions towards other cats being surprisingly friendly.
Researchers observed 53 domestic cats in a cat cafe over 10 months, recording 186 separate meetings between the animals.
They identified 126 friendly facial expressions, including the peaceful closed-eye expression which cat owners have learned to recognise as a sign of love.
There were 102 unfriendly facial expressions displayed by cats - such as the narrowed pupils and flattened ears which felines also display to humans when they are annoyed.
Cats may look inscrutable, but they actually have almost 300 different facial expressions which they show to each other
Felines are not as hostile as they sometimes seem either, with the majority of their facial expressions towards other cats being surprisingly friendly
The study found only 48 facial expressions which, Cheshire Cat-like, are harder to read, because they can be either friendly or unfriendly.
The huge range of facial expressions took experts by surprise as, compared to dogs, with their grins and mournful puppy dog eyes, cats have relatively immobile faces.
Dr Brittany Florkiewicz, senior author of the study, from Lyon College in Arkansas, said: 'These findings show it is good to look at a cat's ears, eyes and whiskers to understand if they are feeling friendly.
'Their mouth provides a lot of information about whether a cat fight is likely.
'People may think that cat's' facial expressions are all about warning other cats and people off, but this shows just how social and tolerant pet cats can actually be.'
The study, published in the journal Behavioural Processes, observed 276 types of facial expression directed by cats towards other cats.
More than half of these expressions indicated they wanted to play - including a cat's lips being pulled outwards, with their bottom teeth showing, mouth open and jaw stretched.
Usually this playfulness was friendly.
But the telltale signs of cats not getting along, when fur may be about to fly, the study found, are four muscle movements seen in various facial expressions.
The study found only 48 facial expressions which, Cheshire Cat-like, are harder to read, because they can be either friendly or unfriendly
Pictured: An illustration of facial expressions that are significantly more likely to be produced in (B) friendly contexts and (C) unfriendly contexts, alongside a neutral face (A)
To identify the clues, just look for a cat licking its lips, whose ears have moved to the side of the head, and are flattened, and who has narrowed pupils.
The last three of these movements have also been seen in cats unhappy with humans in previous studies.
It is believed cross cats facing the possibility of a cat fight, or even preparing to swat or scratch a human, instinctively flatten their ears and narrow their pupils to protect their head and eyes from injury.
The four muscle movements seen in friendly facial expressions within the study were closed eyes, ears moved closer together, and pushed forwards, and whiskers also facing forward.
These could indicate a cat preparing to rub against another cat or sniff them inquisitively.
Researchers were able to identify friendly and unfriendly cat facial expressions based on the context, like whether cats ended up gently touching or hissing and running away.
The study could help owners better understand their cat's' behaviour, and when they need some alone time.
Cats were found to have 26 unique facial movements which form their expressions, compared to 27 in dogs and 44 in people.
HOW WELL DO YOU KNOW YOUR CAT? THE 13 SECRET SIGNALS FELINES GIVE THEIR OWNERS
Cats are often branded aloof and solitary creatures who spend their days plotting their human owner's demise, but such characterisations could not be further from the truth.
In fact, our feline friends constantly communicate their feelings of affection to us, whether it be through their whiskers, tail, face or body language.
In her eye-opening new book Kitty Language: An Illustrated Guide to Understanding Your Cat, author Lili Chin - with the help of animal behaviourists - explains how to interpret your pet's movements.
Below are some of the most common behaviours and what they could signal.
Our feline friends constantly communicate their feelings of affection to us, whether it be through their whiskers, tail, face or body language