Smelly organic compounds from male cats are actually made not by the animals, but by bacteria living in their anal sacs, according to new research reported in the journal PLoS ONE.
Cats and many other mammals (dogs, bears, pandas, skunks and hyenas) use secretions from their anal sacs as a chemical language or a mean of defense.
“Cats use a lot of volatile chemicals for signaling, and they probably don’t make them all,” said Dr. David Coil, project scientist in the Genome Center at the University of California, Davis.
Dr. Coil’s team tested the so-called fermentation hypothesis — the idea that symbiotic bacteria living in association with cats contribute to odor profiles used in their chemical communication.
For the study, the researchers obtained anal sac secretions from a male Bengal cat (Felis catus x Prionailurus bengalensis), a cross between the domestic cat and the leopard cat.
They extracted DNA for sequencing to identify types of bacteria, and also took samples for chemical odor analysis.
Three bacterial species — Bacteroides fragilis, Tessaracoccus, and Finegoldia magna — were abundant in the sequence data and also isolated by culturing.
The team identified 52 compounds from the Bengal cat anal sac secretions and 67 compounds from cultures of the three bacterial isolates.
Among 67 compounds identified from bacterial isolates, 51 were also found in the anal sac secretion.
“We show that the bacterial community in the anal sac consists primarily of only a few abundant species and that isolates of these species produce numerous compounds that are found in the combined anal sac profile,” Dr. Coil and colleagues said.
“Several of these compounds are found in anal sac secretions from other carnivorous mammals, and are also associated with known bacterial biosynthesis pathways.”
“This is consistent with the fermentation hypothesis and the possibility that the anal sac is maintained at least in part to house bacteria that produce volatiles for the host.”
M.S. Yamaguchi et al. 2019. Bacteria isolated from Bengal cat (Felis catus x Prionailurus bengalensis) anal sac secretions produce volatile compounds potentially associated with animal signaling. PLoS ONE 14 (9): e0216846; doi: 10.1371/journal.pone.0216846