The effect of familiarity on vigilance behaviour in grey squirrels

Abstract

Introduction: Vigilance enables an animal to obtain information about the environment but often at a cost of reduced foraging rate. some environmental information may not change rapidly, so vigilance might be safely reduced with familiarity with an area. studies have noted this decline
in vigilance with familiarity, but the reason for this decline has not been tested. Methods: I proposed and tested two hypotheses to explain this decline in vigilance. The safe experience hypothesis suggests the probability of a predator being nearby but undetected decreases with time spent in an area, enabling an animal to decrease its vigilance due to the reduced risk. The Visual experience hypothesis suggests that as time progresses vigilant animals acquire more information from their surroundings (e.g. refuge locations) allowing for a decrease in vigilance because an animal would not need to detect a predator as early if reaching a refuge required less time. grey squirrels (Sciurus carolinensis) were used to test these hypotheses by feeding them peanut butter in an apparatus that limited their access to visual information by varying degrees. results: An effect of familiarity was evident by a sharp decline in vigilance rates within trials. squirrels adjusted vigilance postures to the different treatments, but the rate of decline in vigilance was unaffected by treatment. discussion: while vigilance is related to visual information, the decline in vigilance with familiarity is not related to the amount of visual information obtained from the environment, giving provisional support to the safe experience hypothesis.