Juvenile Free-Living Ground Squirrels Utilize Responses Known as "Alarm Calls;

Essay

Juvenile free-living ground squirrels utilize responses known as "alarm calls;" that is, vocalizations elicited by a predator. These calls can alert others to danger from a predator. Newly weaned squirrels emerge from the nest at about 25 days of age and enter a noisier world than they are used to. Do the squirrels emerge with automatic responses to alarm signals, or are the responses learned? To answer this question, a biologist played recordings of alarm calls for three populations (by age) of squirrels and observed the squirrels' responses. She reasoned that if the responses were not different for the different age groups, the squirrels must be responding by instinct. On the other hand, if the responses differ with the age of the squirrels the young squirrels must be learning to respond to the alarm calls. Her data for the responses to a whistle chorus, categorized by age, is presented below: Is there convincing evidence that the responses to a chorus of whistles are different for the different age groups? Test the relevant hypothesis at the .05 level.