A new Current Biology study says the long-mysterious lipid droplets packed into domestic cat kidneys act as a reservoir that keeps each cat’s urine scent signature chemically stable over time.
The mechanism centers on 13 branched-chain fatty acids found almost exclusively in the kidney: each cat carries a distinctive mix and ratio, and those compounds evaporate slowly enough to remain detectable for at least a day.
Behavior tests backed the chemistry, with cats showing stronger flehmen responses to unfamiliar urine, losing interest with repeated exposure to the same sample, and detecting fatty-acid differences even when other urine components were fixed.
Related kidney droplets and compounds also appeared in lions, tigers, leopards, jaguars and lynxes, suggesting the reservoir-supported signaling system extends across felids.
The finding helps resolve a roughly 110-year puzzle in cat biology and could aid urine-odor management while giving conservationists a possible scent-based way to identify elusive wild cats.