Comparison of volatile compounds of anal sac secretions between the sexes of domestic dog (Canis lupus familiaris)

Volatile compounds of anal sac secretions are odorant chemicals used across the carnivores for social communication such as identifying individuals and group membership. Odor profiles taken from expressed anal sac secretions of some species of carnivores have been detected in previous studies. In this study, the volatile compounds of anal sac secretions between five male and five female domestic dogs (Canis lupus familiaris) were compared. Volatile chemicals were extracted, separated, and analyzed by gas chromatography-mass spectrometry with solid-phase micro-extraction and identified from their electron ionization mass spectra and Kovats retention indices. The results showed the presence of various types of compounds including organic fatty acids, ketones, aldehydes, esters, and alcohols in the anal sac secretions of dogs. Greater amounts of diversity and esters, and lower amounts of alcohols were detected in the anal sac secretions of females compared to males. This was accompanied by finding citrate and acetic acid ester only in the females. Furthermore, presence of some sex-specific organic compounds like dimethylcyclopentyl ethanone indicates that the volatile profiles of anal sac secretions in 10 domestic dogs are differentiated by host sex.