Bioacoustics of the laboratory guinea pig: Behavioral responses to ambient anthropogenic noise

Animals in managed environments are surrounded by human generated (i.e. anthropogenic) stimuli over which they cannot exert control. Laboratory animals, in particular, are exposed to potentially disturbing noises associated with routine husbandry procedures. The evolutionary novelty of such noises may distress these animals and because they cannot exert control, they may suffer from the consequences of chronic stress. Until recently, limited research has been conducted on the effects of ambient noises on laboratory animal behavior and welfare. The goal of this study was to determine how ambient anthropogenic noise in a typical laboratory setting impacts the behavior of a commonly used animal, the guinea pig. To accomplish this, I evaluated whether guinea pigs would remove themselves from noise if provided with the opportunity to do so. I supplied two shelters that differed in their sound-attenuation properties to guinea pigs and recorded their shelter use patterns. The guinea pigs utilized both shelters, but contrary to predictions, they preferred the control over the sound-attenuated shelter. Next, I identified two acoustic parameters, frequency and amplitude, that reliably predicted shelter use. I then created three pure tone frequencies at three amplitude ranges to play to the guinea pigs to determine if the playbacks would elicit shelter-seeking responses. Alert-related behaviors were consistently elicited by the lower and mid-range frequencies, though no playbacks caused the guinea pigs to seek either shelter. Based upon these results, I suggested two possible explanations. One was that the shelters were perceived by the guinea pigs as control over their environment and mitigated the degree of stress they experienced from the playbacks. Thus, the playbacks did not distress the guinea pigs enough to elicit shelter-seeking behavior. The other explanation that may not be mutually exclusive was that the form of the playback tones was not sufficiently distressing to elicit immediate shelter-seeking behavior. Through this study, I demonstrated that guinea pigs may perceive some aspects of ambient anthropogenic noise as disturbing. Further research is necessary to determine if such disturbing stimuli actually cause distress and if the provision of opportunities to control their exposure to such stimuli can improve guinea pig welfare.