The influence of amplitude modulation on the structure of call spectrum in marmots (Marmota, Rodentia, Sciuridae)

A relationship was established between the amplitude modulation and the structure of call spectrum in animals by the example of alarm call in three marmots (Marmota sibirica, M. menzbieri, and M. caudata). In the case of amplitude modulation, side frequencies are produced higher and lower than the carrier frequencies. In the absence of amplitude modulation, no side frequencies are produced. © 2007 Pleiades Publishing, Inc