Sex Differences in Foraging Rats to Naturalistic Aerial Predator Stimuli

Rodents in the wild are under nearly constant threat of aerial predation and thus have evolved adaptive innate defensive behaviors, such as freezing or fleeing, in response to a perceived looming threat. Here we employed an ethologically relevant paradigm to study innate fear of aerial predators in male and female rats during a goal-oriented task. Rats foraging for food in a large arena encountered either a 2D or 3D looming stimulus, to which they instinctively fled back to a safe nest. When facing a direct aerial threat, female rats exhibited a greater fear response than males and this divergence maintained when exposed to the environment on subsequent days with no predator interaction, suggesting stronger contextual fear in female rats. These results may have relevance toward exploring neurobiological mechanisms associated with higher diagnosis rates of fear and anxiety-related disorders in women as compared with men.