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Show Zo o logis t s ays yes Do animals really talk? By MADELEINE JACOBS Smithsonian News Service An aggressive woodpecker wood-pecker and an angry African elephant might not apear to have much in common, but to Dr. Eugene S. Morton, a research zoologist at the Smithsonian's National Zoological Park, the two are literally "birds of a feather." What the woodpecker, elephant and a whole menagerie of birds and mammals including humans share is a similar approach to communication, Morton says. After more than a decade studying sounds used by animals to "talk" to each other, Morton has developed a theory with enormous potential for understanding the evolution and meaning of all animal language. Simply stated, the theory proposes that there are three major elements found in all animal language: a low harsh sound, or "growl," used in hostile or aggressive situations; a higher, tonelike sound, or "whine," used in appeasing or friendly situations, and a sound that falls somewhere in between, a so-called "bark," which is used to indicate indecision or to attract attention. With these three elements and their variations, Morton says, animals can express a wide range of feelings or motivations. Most important, im-portant, the actual physical or acoustical structure of the sounds directly reflects the animal's intention. Lastly, Morton's theory explaining why this system evolved is compatible with Darwin's Dar-win's theory of natural selection that, because of more efficient reproduction, well-adapted well-adapted or "fit" individuals in-dividuals thrive and poorly adapted individuals in-dividuals die out. It may seem strange to think of birds barking and growling and elephants whining, Morton admits. But if you've ever stood in a corn field and listened to a common crow attacking at-tacking a rival, you'd recognize the crow's sound as a definite growl. "The Carolina wren barks, growls and whines," says Morton, an ornithologist by training who has studied the species in detail, "depending on whether it sees something alarming, is attacking a rival or is approaching its mate." The African elephant makes a deep, roaring, rumbling sound when it's charging and a high frequency sound when it is being "friendly." The common household dog often growls at an intruding in-truding mutt, but may well whine or whimper if. it's trying to make friends or back off from a fight. In short, from the rhinoceros to the chickadee, a wide variety of mammals and birds share these vocal elements. Morton originally came to this conclusion after studying the sounds that birds use in a variety of situations. He expanded his studies to mammals and found the same - patterns, which have been confirmed by analyzing animal sounds with a sonagraph. j A sonagraph is an instrument in-strument that converts sounds into a two dimensional picture a sonogram showing frequency or pitch changes with time. When sonagrams of growls, barks and whines are examined,, certain common pictorial features are obvious. The growl, whether from a pelican or pig, shows up as a thick, black band at low frequency. |
