Bioacoustics. The International Journal of Animal Sound and its Recording, 1998, Vol.9, pp. 197-206

INDIVIDUALITY IN THE WHISTLE CALL OF THE ASIATIC WILD DOG (Cuon alpinus)

LEON S. DURBIN

Institute of Terrestrial Ecology, Banchory, Aberdeenshire AB31 4BY, Scotland, UK.

SUMMARY

The IUCN has called for more information on the abundance and distribution of the vulnerable Asiatic wild dog, or dhole (Cuon alpinus). At present there are no established survey methods, and surveying is difficult because dholes live in packs where the individuals look very similar. The aim of the present study was to investigate the feasibility of an acoustic survey technique, based on differentiating the calls of individuals. The whistle is a repetitive, medium range contact call used by dholes to re-group in dense habitats. Its volume and stereotyped structure suggest it might be suitable for surveying, so in captivity we investigated how individually distinct these calls were.

Whistle bouts were recorded whenever the caller could be visually identified (n=67 from 8 individuals). Holistic comparisons of these whistle spectrograms using cross-correlation analysis, revealed significant differences between individuals. Six structural parameters of whistles were measured. Those explaining most of the individual variation were the cycle duration (i.e. the interval from the beginning of one whistle syllable to the next), and the fundamental frequency (see Figure). Furthermore, Discriminant Function Analysis assigned 90% of the whistles to the correct animal.

These results demonstrate that the whistles can be individually distinctive, even when comparing first order relatives of the same age and sex. Whistle recognition may therefore have survey applications, but this will depend on the ease with which calls can be recorded in the wild. Field observations are necessary to assess this.