Vocalizations

Better heed the call of the wild!

You've probably noticed that you use one voice when your dog is digging in the flowers, and another when you're inviting the dog onto the sofa. Other animals, especially mammals and birds, use various tones of voice too. The tendency by different kinds of animals to use certain sounds to express similar messages is known as Morton's rule.

© Steve Kaufman

According to Morton's rule, growls and other low-pitched sounds are warnings. They say, "Go away!" Whimpers, yelps, and other high-pitched sounds plead, "Pay attention to me," or "Come closer."

The harshness of the sound indicates how much "meaning" or "depth" is behind the sound. An extremely harsh yelp would convey the dog is in significant pain, rather than a mellow yelp which might carry a message of "pay attention."

© Paula White

Most dog barks are neither high nor low in pitch but rather a mixture. They start fairly high, then drop in pitch. These send mixed messages: "Go away, come here."

The reason that low-pitched sounds are threatening is probably because larger animals tend to make them. Pitch decreases with body size in mammals simply because vocal cords become longer and must vibrate at lower frequencies. When we hear a deep voice, we think big person and we are usually right.

© Monty Sloan/Wolfpark.org

To bark or not to bark

Wolves rarely bark except as an alarm, but most dogs bark often and everywhere. There are alarm barks, "let-me-outside" barks, "I-want-to-play" barks, and more. All this barking may be a result of early breeding of the first dogs where humans selected for effective guarders -- more specifically, the noisiest!

One breed of dog never barks -- the African basenji.

Last laugh?

Recent research has discovered distinct vocalizations made by playing dogs. Could these sounds be dogs laughing? When researchers play the sounds for a group of dogs at rest, some of the dogs will grab toys and try to get their buddies to play.