Experimental Assessment of the Effects of Substrate Choice on the Duration of Chemical Signals in Fecal Scent‐Marks of Free‐Ranging Iberian Wolves

Chemical communication, typically based on feces, urine, and glandular secretions, often deposited as substrate scent marks, plays a key role in social organization and communication among many mammals, especially carnivores. This study assesses experimentally whether the type of substrate chosen for fecal deposition and the temperature reached by these substrates influence the persistence of volatile compounds in feces of the Iberian wolf (Canis lupus signatus), considering their role in chemical communication. Fresh fecal scats collected in the wild were divided into equal fragments and positioned in an experimental setup on four different types of substrates exposed to the natural environment. Thereafter, we collected small fecal samples from each fragment at seven different time intervals since the initial deposition and analyzed their lipophilic chemical composition using gas chromatography-mass spectrometry (GC-MS). Variations in the temperature of each substrate were also monitored. The number of compounds in feces decreased with time since deposition and depended on the types of substrates. However, substrate temperature only influenced the persistence of some chemical compounds. These results suggest that when wolves select a substrate to deposit feces, enhancing visual cues (i.e., the different visual conspicuity of feces in different substrates) may play a more important role in fecal marking than trying to increase the persistence of the chemical signal. Overall, our study may help to enhance the understanding of fecal marking behavior in the Iberian wolf, especially regarding the interplay between visual and chemical signaling.