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

Cats communicate through scent, and urine marking allows them to leave a lasting message for others to discover. Scientists have discovered a group of unusual chemicals in domestic cat urine that create a distinctive signature for each animal. These chemicals, known as 13 branched-chain fatty acids (BFAs), form a unique chemical calling card that remains relatively stable even after being deposited.

The research, led by Japanese scientists from Iwate University and published in Current Biology, identified these BFAs as the key to individual cat identification. The proportion of these compounds in a cat's urine is unique to each animal, with related cats sharing more similar profiles. The BFAs may help cats convey their identity in the environment, as they evaporate more slowly compared to other smell-causing chemicals.

Laboratory tests showed that individual BFA patterns remained stable for at least 24 hours after being deposited. Not only can humans clean up a patch of cat urine, but cats themselves can also recognize the chemical profiles of other cats' urine. When reintroduced to the same scent repeatedly, cats gradually lose interest, but become engaged again when exposed to urine from a different cat.

The researchers also found that these BFAs originate from lipid droplets stored in cat kidneys, structures that have puzzled scientists for centuries. These findings offer a glimpse into the sensory world of cats, which often goes unnoticed by humans.