Vocal communication in free-ranging African wild dogs (Lycaon pictus)

From 1992-1998, a study of up to six radio-collared packs of free-ranging African wild dogs (Lycaon pictus) was conducted in Hwange National Park, Zimbabwe. Wild dogs were primarily observed during the day and data were collected across seasons on vocalizations and social context. An analysis of spectral properties, along with an examination of context and function, is presented. A vocal repertoire consisting of 11 vocal classes and 18 subclasses was identified. The sound system of this socially obligate carnivore is among the most complex in Canidac. Several vocal classes, i.e. twitters, begging cries, and rumbles, appear to be unique. Heavy investment in high frequency sounds relative to other social canids is offset by a greater variety of low frequency sounds. More kinds of barks are found in its repertoire than have been reported for other canids. Sound mixing is an integral component of wild dog vocal communication and occurs via succession or superimposition of noisy and harmonic sounds. Mixing by succession occurs for all classes, while mixing by superimposition occurs for yelp/squeals, whines, moans, growls, and barks. The Lycaon vocal repertoire is highlighted by comparison with other social canids (i.e. wolves, bush dogs, dholes, and domestic dogs). Finally, attention is drawn to features in the wild dog sound system that are both consistent and inconsistent with the motivation-structural rules of Morton's model. While most sounds conform to the model, there appear to be anomalies between the expected design features of certain vocalizations (i.e. twitters, barks, and rumbles) and the contexts in which they are given. Some of these anomalies appear to reflect the highly cohesive social system of the wild dog.