UC Riverside Undergraduate Research Journal

Mice exhibit defensive behaviors in response to various predator cues. When a mouse “senses”a predator at a close distance, it exhibits freezing behavior. Alternatively, when it senses bodilyexcretions from a predator, it escapes from the area. These behaviors are evolutionary responses topredators that help their increase survival. How animals sense the different types of predator-derivedcues and induce appropriate behaviors in response to the specific predator cues have largely remainedelusive.In this study, we aimed to establish a method to analyze mouse behavioral responses toward variousforms of predator-derived biological samples, such as cat saliva, which contain chemical cues. Wecategorized mouse responses to predator cue exposure as freezing, fear assessment, or exploratorybehavior, each of which is triggered by different levels of fear that the animal is experiencing. Thebehaviors were quantified manually and compared between the animals exposed to control andpredator-cue stimuli. We show that this protocol is effective in analyzing levels of fear in mice asthere is a significant increase in the occurrence of fear-based behaviors in mice exposed to cat saliva.Developing a strong protocol for quantifying fear-related behaviors is essential to understand brainmechanisms underlying behavioral responses induced by different types of predator cues in mice.Moreover, the present protocol can be further utilized to understand how different levels of fear areprocessed in an animal’s brain circuitry.