How Cats Use Scent to Identify Each Other
Cats can recognize each other through scent marks, even long after the marks are left. This is a puzzle because scent molecules usually change over time. Now, scientists from Japan, Germany, and Spain have found a possible answer in domestic cats.
They discovered 13 special branched-chain fatty acids (BFAs) in cat urine. The mix and amounts of these BFAs are unique to each cat. But they stay pretty much the same for that individual cat. This suggests BFAs act like a chemical "calling card" that helps cats identify each other.
The Role of Kidney Lipid Droplets
The research team first showed that cats could tell different urine samples apart. Cats spent less time sniffing urine they had smelled before. Their interest went up when a new cat's urine was introduced. They even remembered urine odors for months.
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Start Your News DetoxCats also showed the "flehmen response" (an open-mouthed expression) more often when smelling unfamiliar urine. This behavior helped researchers find the BFAs.
These BFAs were found in the kidney tissue, but not in other tissues. They were stored in tiny fat droplets within the renal cortex of the kidney. Scientists have known about these kidney lipid droplets in cats for over a century, but their purpose was a mystery.
Professor Masao Miyazaki, who led the study, believes these droplets might store BFA-containing lipids. This storage could keep a cat's urine chemical profile stable, even with changes in diet or health. This helps ensure the scent identity remains consistent.
Broader Implications for the Cat Family
The researchers also looked at other wild cats like lions, tigers, and leopards. They found similar BFA-related compounds in their urine and kidney lipid droplets. The BFA profiles and kidney droplet distribution varied between species. This suggests that this BFA chemistry and kidney function are common across the cat family, but have changed during evolution.
While it's not yet known if wild cats use BFAs for individual recognition, these findings offer a new way to understand chemical communication. It explains how scent marks can provide reliable identity information over time.
This basic research could lead to new ways to manage cat urine odor. It might also help us understand why fat storage in kidneys is sometimes harmless and sometimes linked to disease. In the future, analyzing BFA profiles from scent marks could even help monitor rare wild cats for conservation efforts.
Deep Dive & References
Signatures of branched-chain fatty acids derived from a kidney reservoir confer stable chemical individuality on domestic cats - Current Biology, 2026
