Cats mark territory with microbe-made stink

(Credit: Ste Pagna/Flickr)

Cats may owe their stinky way of marking territory to resident bacteria, research shows.

Domestic cats, like many other mammals, use smelly secretions from anal sacs to mark territory and communicate with other animals. The new study shows that many odiferous compounds from a male cat are actually made by a community of bacteria living in the anal sacs.

“Cats use a lot of volatile chemicals for signaling, and they probably don’t make them all,” says David Coil, project scientist at the Genome Center at the University of California, Davis and an author of the paper in PLOS ONE.

Many species—including cats, dogs, bears, pandas, skunks, and hyenas—use anal sac secretions as a chemical language. Skunks, of course, also use them as a means of defense.

The project grew out of the KittyBiome Project, now a spin-off called AnimalBiome, which postdoctoral researcher Holly Ganz started with Coil and Jonathan Eisen, professor of evolution and ecology.

The researchers obtained anal sac secretions from a single male Bengal cat whose owner volunteered it to participate. They extracted DNA for sequencing to identify types of bacteria, and also took samples for chemical odor analysis in Professor Cristina Davis’ laboratory in the mechanical and aerospace engineering department.

Davis’ lab focuses on technology for detecting and characterizing low levels of volatile organic compounds that can be markers of health and disease, from influenza in humans to citrus greening in fruit trees.

Sequencing showed that the microbial community was not very diverse and dominated by a small number of bacterial genera. “There are not a lot of players there,” Coil says.

The researchers grew the most abundant bacteria from the screen in culture. Postdoctoral researcher Mei Yamaguchi analyzed the volatile chemicals that the bacteria gave off.

Yamaguchi and Davis were able to detect 67 volatile compounds that the bacterial cultures released. Of the compounds, 52 were also found directly in the anal sac secretions.

The results support the idea that the bacterial community, not the cat itself, produces many of the scents the cat uses to communicate.

Coil and colleagues want to follow up by looking at more cats. If bacteria make these scents, why do cats smell different from each other? How do cats acquire the bacteria and do they change over life? Understanding how microbes influence their scent could have wide implications for understanding scent communication in animals.

The KittyBiome Project and the National Institutes of Health supported the work.

Source: UC Davis