Barking foxes, Alopex lagopus:: field experiments in individual recognition in a territorial mammal

During field studies on a wild population of Arctic foxes, Alopex lagopus, on the Commander Island Mednyi (Northern Pacific) we examined whether acoustic long-distance signals were used for individual recognition. Barks of 10 individually known animals from five neighbouring groups were tape recorded. The spectral characteristics of the barks were described in terms of averaged 1/12 octave spectra. With a discriminant function analysis, more than 90% of the calls could be assigned to the correct individual on the basis of the spectral parameters. Discrimination was only slightly improved when we added temporal parameters to the analysis. We carried out playback experiments with eight foxes near the territory boundary of their family groups. The foxes were significantly more likely to respond with territorial behaviour and longer barking bouts to playbacks of neighbours or strangers than to playbacks of group members. We conclude that individuals can distinguish between barks of members of their own social group and those of other foxes. (C) 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.