Cats have a knack for turning even the simplest nap into an art form. Whether they’re curled up like a croissant, sprawled across your bed, or softly purring in a patch of sunlight, their sleeping habits are endlessly fascinating.
But have you ever noticed your cat tends to sleep more on one side than the other? A new international study has revealed that this isn’t random, most cats actually prefer sleeping on their left side, and there’s a scientific reason behind it.
This article is for general knowledge only and is based on information from scientific publications and veterinary researchers. Every cat is unique, and sleeping positions may vary. Photos are for illustrative purposes only.
1. What The Study Found
Researchers from multiple countries joined forces to understand feline sleeping patterns in ways nobody had explored before. Dr. Sevim Isparta and Professor Onur Güntürkün led a team that included experts from Italy, Germany, Canada, Switzerland, and Turkey.
They analysed 408 YouTube videos of sleeping cats, carefully selecting clips where a single cat rested on one side for at least ten seconds. Only unaltered videos made the cut.
Published in Current Biology, their findings revealed something remarkable: two-thirds of cats slept on their left side, suggesting this wasn’t mere coincidence but rather an evolutionary adaptation linked to survival instincts.
2. The Evolutionary Advantage Of Sleeping Left
Wild cats spend much of their day sleeping, which leaves them exposed to potential predators. Sleeping on the left side may offer a biological edge by keeping the right brain hemisphere more alert during rest.
The right side of the brain processes input from the left visual field and handles spatial awareness, threat detection, and quick escape coordination. These are all vital skills for survival in the wild.
Even when your cat looks blissfully relaxed, their brain may still be quietly assessing their surroundings, ready to respond if something startles them, making this position both restful and protective.
3. Why Brain Asymmetry Matters
Professor Güntürkün explained that asymmetries in behaviour can have advantages because both hemispheres of the brain specialize in different tasks. This lateralisation is the way each side of the brain handles different functions, and it’s common in animals and humans alike.
For cats, the left-side sleeping position allows their body and brain to work together in a way that feels safest and most natural. Each hemisphere takes on specific roles, creating a balanced system.
This specialization means cats can rest deeply while maintaining a level of environmental awareness that their ancestors relied on for survival.
4. How Researchers Ensured Accuracy
Scientific rigour was essential to this study. Each video needed to meet strict criteria before being included in the analysis.
The team made sure every clip featured a single cat resting on one side for at least ten seconds, eliminating any videos that appeared edited or altered. This careful selection process ensured the data reflected genuine, natural feline behaviour rather than staged or manipulated content.
By using YouTube as their source, researchers accessed a diverse, global sample of cats in their home environments, providing insights that laboratory settings might have missed entirely.
5. What It Means For Pet Owners
Cat owners now have a fresh perspective on their pet’s quirky habits. If your cat often snoozes on their left, it’s not just a random preference but part of an ancient instinct rooted in survival.
Cats are individuals, though, and comfort still plays a big role in how they sleep. Some may switch sides depending on temperature, light, or even where you’re sitting nearby.
Next time you catch your cat curled up in that familiar left-side pose, remember they’re not just napping but quietly balancing relaxation and readiness, just as their ancestors did thousands of years ago.
