Sex Differences in Foraging Rats to Naturalistic Aerial Predator Stimuli

Peter R Zambetti,Bryan P Schuessler,Jeansok J Kim

doi:10.1016/j.isci.2019.06.011

Abstract

SummaryRodents 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.

Highlights

The study of fear in laboratory rats and mice has traditionally utilized paradigms concerned with basic associative fear learning or how fear of specific stimuli are acquired (Kim and Jung, 2018)
Used by ethologists (Kavaliers and Choleris, 2001; Schleidt et al, 2011), innate fear paradigms often use predator cues (Takahashi et al, 2005), or in some cases, actual or simulated predators (Blanchard and Blanchard, 1989; Choi and Kim, 2010) to elicit fear responses. Responding to such predatory stimuli does not require previous experience or learning about the stimuli over multiple trials, and fear toward these stimuli is considered to be genetically ‘‘pre-wired’’ (Ohman and Mineka, 2001). These ethologically relevant fears offer an evolutionary advantage over trial-and-error learning typical of associative fear learning, which can be both costly and time consuming for the organism (Pellman and Kim, 2016)
Female Rats Initially Have Increased Foraging Times Than Male Rats Projector and owl encounter rats’ data were pooled together as baseline foraging session methods were identical across experiments and no increase in latency was found from the projector being turned on, leading to baseline sample sizes of 20 male and 17 female rats

Summary

Introduction

The study of fear in laboratory rats and mice has traditionally utilized paradigms concerned with basic associative fear learning or how fear of specific stimuli are acquired (Kim and Jung, 2018). Used by ethologists (Kavaliers and Choleris, 2001; Schleidt et al, 2011), innate fear paradigms often use predator cues (Takahashi et al, 2005), or in some cases, actual or simulated predators (Blanchard and Blanchard, 1989; Choi and Kim, 2010) to elicit fear responses Responding to such predatory stimuli does not require previous experience or learning about the stimuli over multiple trials, and fear toward these stimuli is considered to be genetically ‘‘pre-wired’’ (Ohman and Mineka, 2001). The use of innate fear paradigms in fear research has been steadily increasing (Kim and Jung, 2018)

Results

Discussion

Conclusion