With wolves, vocalization serves a variety of needs: howls often represent a gala social pack "sing"; whines may indicate concern or discomfort or serve as a call for help; yips, growls, and barks alert to intruders, establish status according to pack hierarchy, let pack members stay in touch with each other even from a distance, and help lone wolves develop new packs with other loners. With their sharp sense of hearing and their ability to discern nuances in other wolves' sounds beyond human comprehension, wolves have developed a very vocal language that is understood clearly by all other wolves. In dogs, vocalization has evolved to another level. Certain breeds, such as hounds, have transformed the wolf's howl into a "bay," used to spur other hounds, as well as the hunter, into the chase. This same vocal message is given to you by your dog when he barks to get your attention, to say "Follow me!" For us, vocalization is the most obvious form of DogSpeak. To a dog, it's just one more grammatical tool.
From DOGSPEAK by Bashkim Dibra. Copyright © 1999 by Bashkim Dibra. Reprinted with permission of Simon & Schuster, Inc.