Communication networks can be found in any taxonomic group of animals, all that is required is that their signals travel further than the average distance between individuals. This potential for taxonomically widespread occurrence is one of the reasons that communication networks are likely to be an important concept for the understanding of communication in general. However, taxa vary considerably in several aspects that could affect communication networks, including the senses used by receivers (signal modality), processing power and social organization. The potential insights gained from such taxon-related differences are the reason for grouping chapters into this section.

Not all taxa are covered in Part III: for example, fish do not appear, but they do in Parts I and IV (Chs. 4, 5, 21, 22 and 23). Also some taxa are underrepresented: there is a preponderance of endothermic vertebrate groups, which is recognized to be a general feature of the literature (Bonnet et al., 2002), and invertebrates have many fewer chapters than their species richness would seem to require. The invertebrate balance is redressed slightly by the fact that insects are the focus of a chapter elsewhere in this book (Ch. 8) and by recent books on insect communication that deal extensively with chorus behaviour (e.g. Gerhardt & Huber, 2002; Greenfield, 2002). Nevertheless, this part does have chapters ranging from fiddler crabs to humans and that is a sufficiently broad taxonomic coverage to demonstrate common themes and illuminating differences.