The alarm call of Himalayan marmot (Marmota himalayana, Rodentia, Sciuridae)
Alarm calls of Himalayan man-not were recorded in Kun-Lun (China), Central (Nepal) and Western (India) Himalayans in field conditions. The alarm call is a series of sounds. The interval between the series is typically 5-20 s. Each series consists of short rapidly emitted sounds. Usually, series last less than 1 s; the duration of each sound is less than 80 ms. Quite often, additional sounds may appear between the main sounds. They are significantly shorter and have less amplitude than the main sounds. The intersound period of the main sounds is 2-3 times longer than the duration of sound. The distinctive feature of alarm call in Himalayan marmot, if to compare with other species of Marmota genus, is a close position of the first and the second sounds in series as a result of the fading phase of frequency modulation in the end of the first sound and beginning of the second one. As a result, the interval between the first and the second sounds in series becomes much shorter. The value of the high-frequency component grows rapidly in the beginning of the sound within a relatively wide range and has short fading part in the end of the sound. The first and the second sounds in series are exceptions. Similar to alarm call in marmots from the bobak group, each sound of alarm call in Hymalayan marmot starts with the low-frequency component. Its expression varies in different animals. This study confirms the species specificity and relationships between alarm calls in Hymalayan marmot and marmot of the bobak group based on the presence of the low-frequency component. The name M. bobak used for Hymalayan marmot (prevalent in scientific literature) is mistaken. The spectral structure of the Hymalayan marmot alarm calls leads to the assumption that the call forms are a result of biphonation. In vocalization, the animals use simultaneously two acoustic sources. The low-frequency component is formed by one of the sources, the high-frequency component, by the other one.