Secret 'messages' in cat pee let felines identify each other — and scientists just cracked the code

Cats can identify each other based on the scent of their pee, and researchers have just decoded the secret "messages" that make that possible.

A group of chemicals called branched-chain fatty acids (BFAs) help give cats their unique scent marks, a new study found. Unusual fat droplets in the cats' kidneys likely help them maintain that chemical fingerprint in each mark. The researchers reported their findings Aug.ust 19 in the journal Current Biology.

While most animals use a combination of visual, audible and scent-related cues to recognize each other, some also rely on specific chemical signatures. A number of insects, for example, use certain hydrocarbons to determine whether other insects are part of the same colony, and mice excrete urinary proteins that provide identifying informa...