SITUATIONAL SPECIFICITY IN ALPINE-MARMOT ALARM COMMUNICATION

We studied the degree to which alpine marmot (Marmota marmota L.) alar m calls function as communication about specific external stimuli. Alp ine marmots emit variable alarm calls when they encounter humans, dogs , and several species of aerial predators. The first part of the study involved observations and manipulations designed to document contextu al variation in alarm calls. Alarm calls varied along several acoustic parameters, bur only along one that we examined, the number of notes per call, was significantly correlated with the type of external stimu lus. Marmots were more likely to emit single-note alarm calls as their first or only call in response to an aerial stimulus, and multiple-no te alarm calls when first calling to a terrestrial stimulus. This rela tionship was not without exceptions; there was considerable variation in the number of notes they emitted to both aerial and terrestrial sti muli, and a single stimulus type - humans - elicited a wide range of a coustic responses. The second part of the study involved playing back three types of alarm calls to marmots and observing their responses. M armots did not have overtly different responses to the three types of played-back alarm calls. Our results are consistent with the hypothese s that: 1. Alarm calls do not refer to specific external stimuli; 2. A larm calls function to communicate the degree of risk a caller experie nces; and 3. Alarm calls require additional contextual cues to be prop erly interpreted by conspecifics.