Working hypotheses on the meaning of general alarm calls

General calls are present in the vocal repertoire of a great number of animal species. Because of their lack of context specificity, they are typically argued to possess blurred meaning, or even no meaning at all. Although recent animal cognition studies have demonstrated a growing interest in these vocalizations, there is currently no clear definition of general calls, and their meaning is seldom discussed. Here, we propose a definition of general calls, and review various hypotheses regarding their meaning, focusing on alert contexts. We first discuss the hypothesis that general alarm calls have a general alert meaning. Second, we review an alternative view, that general calls in fact have a specific meaning. With this review, we encourage further research that could help delve into the mechanisms underlying vocal production and comprehension and would improve our understanding of general and specific calls in animals.