Individual, intersexual, and interbreed variability of barks in the dog Canis familiaris (carnivora, canidae)

Dog barks are complex in their structures and may vary from purely tonal to noisy even within individual barking bouts. The possibility to recognize individuality, sex, and breed in Borsoi and Hortaj Windhound breeds based on their acoustical cues was studied. Throughout 2002-2004, barks of 18 Hortaj and 9 Borsoi dogs (kept in a kennel) were recorded in the standard situation, when the same known person approached them. Discriminant analysis of the data on 1329 barks from 11 Hortaj and 9 Borsoi dogs showed 63.5% of their correct assignment to the dogs that exceeded the random value (9.3%). The average value of the correct assignment to sex (358 barks from 12 females and 375 barks from males) was as low as 67.9% (with a random of 58.7%). The value of correct assignment to breed (630 barks from 16 Hortaj and 630 from 8 Borsoi dogs) was only 71.6% (random 54.3%). These results suggest that barks provide for the information concerning individuality of a dog, and to a lesser extent, its sex or breed. The greater breed-dependent than sex-dependent differences in barks arise from greater differences in sizes between the breeds than between sexes. Barks of 3 females and 2 males of Hortaj dogs were tested in order to estimate stability of acoustic features responsible for the recognition of individuality. They were recorded twice with an interval of more than 11 months. The cross-validation analysis of barks recorded during 2003-2004 using discriminant functions of 2002 showed only 38.9% of correct assignment to dog. One can propose that a directional shift in bark characteristics took place due to replacement of a cagemate.