Your cat may leave a ‘calling card’ behind when it pees

A cat's urine may carry a unique "calling card" that helps other cats identify them, according to a recent study. To humans, cat urine is often an undesirable mess to clean up, but for felines, it can provide crucial information about their environment and fellow cats. Researchers at Japan's Iwate University identified 13 specific chemicals in cat urine that form a distinctive signature for each animal, functioning as a sort of chemical calling card.

The key to these chemical signatures lies in a group of branched-chain fatty acids (BFAs). Unlike other volatile compounds that quickly evaporate, these fatty acids remain stable for at least 24 hours after being deposited in the urine. This stability suggests that cats rely on BFAs as a chemical marker that remains consistent over time, even after the scent has dissipated.

Genetics may play a role in determining an individual cat's BFA profile, as related cats tended to have more similar profiles. However, even individual cats could be distinguished from one another based on their unique chemical signatures. When presented with urine samples repeatedly, cats gradually lost interest in the familiar scent but became curious again when a different cat's urine was introduced. This suggests that cats can distinguish between chemical profiles based on BFA composition.

The study also revealed that BFAs originate from lipid droplets found in cat kidneys. These structures, known for over a century, were previously thought to have an unclear function. The research suggests that these droplets may act as a reservoir, stabilizing the mix of fatty acids in urine despite changes in diet or physiology. Similar chemical and kidney characteristics were also observed in other members of the cat family, although it remains unclear whether wild felids use this system to recognize individuals.

In essence, a cat's urine may appear to us as an unpleasant household accident, but to another cat, it could serve as a personalized nametag or calling card, offering valuable information about the cat's identity and individuality.