Evaluating the functional, sexual and seasonal variation in the chemical constituents from feces of adult Iberian wolves (Canis lupus signatus)

Chemical signals play an important role in intraspecific and interspecific communication of many mammals, We described the chemicals found in fresh feces of adult wolves by means of analyses using gas chromatography-mass spectrometry (GC-MS) of samples collected from wild breeding groups. We identified 56 compounds in the feces, mainly heterocyclic aromatic organic compounds such as indole or phenol, but also steroids, such as cholesterol, carboxylic acids and their esters between n-C 4 and n-C 18 , aldehydes, alcohols and significant quantities of squalene and α-tocopherol, which would increase the chemical stability of feces on humid substrates. All samples visually identified as wolves were subsequently identified to species level by sequencing a small fragment of mtDNA and sexed typing DBX6 and DBY7 sex markers. There is variability in the number and proportions of compounds between sexes, which could be indicative of their function as chemical signals. We also found variability in different reproductive states, especially in odorous compounds, steroids and α-tocopherol. Feces with a presumed marking function had higher proportions of α-tocopherol and steroids than feces with non-marking function. Therefore, these compounds could be involved in intragroup and intergroup communication of wolves and their levels could be directly related with the wolf’s physiological status.