Behavioral Responses to Non-Imminent Predator Threat in Mice

Mice as prey animals display a phenomenal sense of smell and thus rely heavily on this sensory modality for social communication and defenses from predators. One of the mouse’s olfactory subsystems is the vomeronasal organ, a specialized organ for the detection of environmental chemical stimuli. This organ plays a central role in semio-chemical detection which has become vital for the survival of the mouse and proliferation of the species. This knowledge then leads to the question of how mice respond to varying levels of intensity of predator cues with the input from this organ. Using cat odor as a predator cue, mouse defensive and non-defensive behavioral responses were compared after exposure to fresh versus 4-hour old odor. Overall, we measured the significant reduction in defensive freezing behavior in response to the 4-hour old cat saliva in male mice as well as the reduction of non-defensive interaction behavior. Female mice expressed no shift in defensive responses between the fresh and old saliva but maintained reduction of non-defensive interaction as well. Mice have shown to exhibit varying defensive responses to predator cues and perhaps may have greater abilities to respond to non-imminent predator threat.