Cats spend longer sniffing the odor of a stranger than that of their owner, suggesting that they can identify familiar humans based on smell alone, according to a study publishing May 28, 2025 in the open-access journal PLOS One by Yutaro Miyairi and colleagues at Tokyo University of Agriculture, Japan.
Cats use their sense of smell to identify other cats and communicate with each other, but whether they can also use smell to distinguish between different humans has not previously been studied. The researchers investigated whether cats are able to distinguish between familiar and unfamiliar humans based on smell alone. They tested thirty domestic cats by presenting them with plastic tubes containing swabs that had been rubbed under the armpit, behind the ear, and between the toes of either their owner or a human they had never met.
The cats spent significantly longer sniffing unknown odors than those of their owner or an empty tube. The researchers also found that cats were initially more likely to sniff unknown odors with their right nostril but later switched to their left nostril as they became more familiar with the smell.
Participating cat owners were also asked to complete an online questionnaire to assess the cat's personality and their relationship with their owner. Male cats with neurotic personalities tended to sniff each tube repetitively, whereas males with more agreeable personalities sniffed the tubes more calmly. However, there was no effect of personality on the behavior of female cats during the experiment.
The results suggest that domestic cats can discriminate between familiar and unfamiliar humans based on their odor, but it remains unclear whether they can identify specific humans based on smell alone. The finding that cats preferred to investigate new smells with their right nostril suggests that they may favor different hemispheres of their brain for different tasks — a phenomenon that has previously been demonstrated in other animals including dogs, fish and birds.
The authors add: "We suggest that cats use their olfaction for the recognition of humans. Also, we record characteristic rubbing (marking) behavior occurring after sniffing, indicating that sniffing may be an exploratory behavior preceding the rubbing of odor (marking) in cats. This relationship warrants further investigation along with the theory of whether cats are able to recognize a specific person from olfactory cues."
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Citation: Miyairi Y, Kimura Y, Masuda K, Uchiyama H (2025) Behavioral responses of domestic cats to human odor. PLoS One 20(5): e0324016. https://doi.org/10.1371/journal.pone.0324016
Author countries: Japan
Funding: The author(s) received no specific funding for this work.
