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Volodina E.V., Volodin I.A., Isaeva I.V., Unck C., 2002. Biphonation enhances a potential for individual recognition in the dhole (Cuon alpinus) // Advances in Ethology. Contributions to the 4-th International Symposium on Physiology and Behaviour of Wild and Zoo Animals. Berlin. V. 37, p. 89.
Pack cohesion is very important for such collective hunters as the dholes, and is based, for the most part, on a repeated emission of especial calls. Our recent study showed that these calls may include a low-frequency pattern (f) or a high-frequency pattern (g), or simultaneous emission of both f and g components, resulting in a phenomenon termed biphonation. The f pattern is a product of focal fold oscillations, whereas there are at least four hypothesises spelling the g production mechanism. What is the communicative role of simultaneous emission of the f and g patterns in the dhole?
 We have compared the impacts of the f and g components both independently and together into individual assignment of the biphonic calls in the dhole. We randomly selected, from tape recordings, 30 biphonic calls from each of 6 subadult dholes from two non-relative litters and analysed them spectrographically on 22 time, frequency, and power parameters. Then we used the discriminate function analysis for assignment to identify individuality of the f and g components taken separately and f and g taken together as the whole of the biphonic calls. The analysis showed average 70,6% of correct assignment for the f component (with nine parameters providing approximately equal impact on the discrimination), 82,8% - for the g component (primarily dependent on two parameters) and 95,6% - for both components together. Our results suggest that the combination of the f and g components into a complex biphonic call, enhances substantially the potential for individual discrimination in the dhole.
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