Vocalizations in wild canids and possible effects of domestication.

On the basis of spectrographic evidence it has been possible to identify twelve basic vocal sound types of canid species. Vocalizations may be mixed either by successive emission of two or more sound types, by superimposition of these sounds, or by a combination of these two forms. The same basic sound type may differ among canid species along the dimensions of sound duration, separation time between consecutive sounds, principle frequencies, cyclicity, and context. Developmental data indicate that domestic dogs first begin to mix sounds by successive sound emissions at about 10 days of age and later by superimposition between 2 and 3 weeks of age. The frequency of occurence of the basic sound types in different contexts varied between species but not within species. The possible effects of domestication on canid vocalizations are discussed.