In the wild, mice have developed strategies to detect volatile cues essential for their survival. These molecules are called semiochemicals. They carry a specific message. Here, the chemical message is signalling the presence of a potential danger. The Grueneberg ganglion (GG), an olfactory subsystem plays a key role in detecting alarm pheromones emitted by stressed conspecifics and kairomones involuntarily released by predators. These volatile chemical cues allow for intra- and interspecies communication of danger, respectively. Alarm pheromones, kairomones and bitter taste ligands share a common chemical motif containing sulfur- or nitrogen-containing compounds. Interestingly, three specific bitter taste receptors (TAS2R115, TAS2R131 and TAS2R143) have been found in GG neurons and seem to be involved in danger signaling pathways. Indeed, recent studies using a cellular expression system, showed the activation of one of them with known GG ligands. To deorphanize the two other TAS2Rs, our research started by identifying new sources of kairomones in secretions from the raccoon (Procyon lotor) and the skunk (Mephitis mephitis). These body secretions not only activated, in a heterologous system, the three TAS2Rs but we demonstrated their ability to activate GG neurons and to induce fear-related behaviors in mice. In addition, we have uncovered a novel role for hydrogen sulfide (H2S), a toxic air pollutant, as a kairomone present in predator secretions. H2S activates a cyclic-nucleotide gated channel A3, the CNGA3, present on the sensory cilia of GG neurons, facilitating calcium influx and neuronal activation. Using GG-axotomized mice, we confirmed the biological relevance of GG neurons in detecting H2S. These findings offer new insights into predator-prey dynamics, interspecies danger communication, underlying the importance of the Grueneberg ganglion in survival-related olfactory signaling and highlighted a potential target of H2S detection in GG-circuitry.