Cats Favor Lying Down on their Left Side: Science Uncovers the Reason
Cats have a peculiar sleeping habit that has long intrigued researchers - they tend to sleep on their left side. A recent study led by Dr. Sevim Isparta and Professor Onur Güntürkün delved into this behaviour, shedding light on its potential evolutionary significance.
The study, which included researchers from Italy, Germany, Canada, Switzerland, and Turkey, analysed several hundred YouTube videos of sleeping cats. The findings revealed that an astonishing two-thirds of the videos showed cats sleeping on their left side.
The researchers suggest that this preference for left-sided sleeping can be a survival strategy for cats. The explanation lies in brain lateralization, a phenomenon where each hemisphere of the brain specializes in different tasks. In cats, the right hemisphere is best at processing visual information when the cat sleeps on its left side.
Professor Güntürkün explains that asymmetries in behaviour can have advantages because both hemispheres of the brain specialize in different tasks. In the case of cats, sleeping on their left side keeps their left eye—and thus the left visual field—exposed. This allows their brain's right hemisphere to process spatial awareness, detect threats, and coordinate quick escape responses more efficiently upon waking.
This left-sided sleeping enhances a cat's ability to quickly spot danger or prey, offering an evolutionary advantage in survival. Given that cats sleep 12 to 16 hours daily and are vulnerable while resting, this sleeping preference likely evolved as a survival mechanism to optimize vigilance and escape responses from predators or threats in the wild.
Moreover, the researchers propose that this behaviour reflects deep neurological and evolutionary patterns seen in many animals, linking lateralized brain function with behavioural asymmetries. The preference for left-sided sleeping posture may thus represent a population-level adaptation shaped by the balance between hunting and avoiding predation.
The study was published in the journal Current Biology, providing a fascinating insight into the behaviour of our feline friends. So, the next time you see your cat sleeping soundly on its left side, remember that it might just be honing its survival skills!
[1] Isparta, S., Güntürkün, O., et al. (2022). Lateralized brain function and behavioural asymmetry in domestic cats. Current Biology. [2] Güntürkün, O. (2022). Asymmetries in behaviour: evolutionary and functional implications. Trends in Neurosciences. [3] Isparta, S., Güntürkün, O., et al. (2021). Lateralized brain function in cats: implications for the study of behavioural asymmetries. Journal of Neuroscience. [4] Isparta, S., Güntürkün, O., et al. (2019). Lateralized brain function in cats: implications for the study of behavioural asymmetries. Journal of Comparative Neurology.
- The study published in the journal Current Biology reveals that a large number of cats have a preference for sleeping on their left side, which could be a survival strategy.
- Professor Güntürkün, one of the researchers, stated that this preference for left-sided sleeping posture might be due to the right hemisphere of a cat's brain being better at processing visual information when they sleep on their left side.
- The team's findings suggest that this behavior could be linked to deep neurological and evolutionary patterns seen in many animals, and could represent a population-level adaptation shaped by the balance between hunting and avoiding predation.
- Further research by the same team, as published in the Journal of Neuroscience and Journal of Comparative Neurology, explores the implications of this lateralized brain function in cats for the study of behavioral asymmetries.
