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| Carl Sagan's COSMOS is one of the most influential science programs ever made.
Q. Does the moon have a dark side?
A. The moon does have a far side which is impossible to see from the earth, but it doesn't mean that it's always dark. Each side of the moon is dark for no longer than 15 days at a time.
Q. Where does sound come from?
A. The air is always filled with sound waves. All things give off vibrations, but some have a low frequency which most cannot hear. The reason: it may take 3 minutes to make a single vibration. They may be caused by earthquakes and storms.
Did You Know?
The microwave was invented after a researcher walked by a radar tube and a chocolate bar melted in his pocket.
Coke-a-Cola was originally green.
Rubberbands last longer when refrigerated.
Infrasound Communication Among Elephants
by Jeanette Cain
From research in Namibia, Zimbabwe, and Kenya, researchers learned elephants use infrasound for communicating over many miles. Elephant calls are outside the pitch of most human ears, but other elephants heed the rumblings.
Researchers were surprised when a group of elephants, usually silent in their daily activities, suddenly took flight for no apparent reason, rather no apparent reason to the researchers watching the show. In unison, the scattered group would stand still in their tracks and raise their ears. Researchers knew this was not the result of using memory, or of using the five senses. There was an unknown factor behind these elephants ability to know of the activities and locations of other elephant herds.
Katharine Payne believed she came across a clue for solving this mystery. She visited the Metro Washington Park Zoo in 1984, and while there observed three Asian elephant mothers and their calves. She kept feeling a throbbing in the air, which she compared to distant thunder. Later, she remembered the deep organ pipe she stood close to when singing in the church choir as a child and recalled the feeling when the entire chapel began to throb as the Bach chorale bass line began to play. She believed this could account for the source of throbbing she had felt when near the Asian elephant mothers, and it was probably used by elephants to communicate by using these type calls, too low-pitched for human ears to detect.
Payne returned six months later with the help of the World Wildlife Fund, the Cornell Laboratory of Ornithology, and Bill Langbauer and Liz Thomas of the Cornell biology department. They tested this theory for a month by making electronic printouts. After studying the charts, they discovered over 400 calls, which was three times the number they had heard with their ears. This included elephant barks, snorts, roars, growls, trumpets, and rumbles. Judith Kay Berg of the San Diego Wild Animal Park had made similar research findings in a 1983 scientific paper. The rumbles are out of range for human hearing, but elephants hear them quite well. The area below human hearing is known as infrasound.
Infrasound can be generated by wind, thunder, volcanos, ocean storms, and earthquakes as the result of huge movements of air, fire, water, and earth. Until this research, low frequency sound was not considered to play a role in the lives of animals. The intense, infrasonic calls of finback whales has been recorded, but researchers are uncertain if this is used in communication. The lowest frequency of an elephant rumble is 14 to 35 hertz, which is also cycles per second. It suffers little when passing through the grasslands and the forests, but is it capable of allowing communication over several miles for elephants to know the location of other herds?
An elephant's forehead skin will flutter and vibrate as air is passed through the nasal passage. Researchers recognize this as the activity of infrasonic vocalizations. Asian elephants at a zoo in Oregon would exchange calls through a concrete wall, which accounts for the ability of adult males and females to live independent lives. Both move over many miles of territory and no fixed breeding season. Elephant males spend a part of every year in musth. During this time, the male makes crisscrosses over large areas in an irritable state hoping to find a female ready for breeding. Elephant females have a two year gestation period with two or more years of nursing, meaning a female will only be receptive for a few days every four or five years.
Researchers were amazed at the quickness of males to locate a female in estrus. She will be surrounded by males who arrive from all directions and from some distance. The dominant male in musth will guard the female in order to mate every few hours until her receptivity ends. It is believed that the female can inform males of her condition with a sequence of intense, but low-frequency calls used by her during estrus. This sequence will always take the same form creating something of a song. The rumbles begin as slow and deep, but rise in pitch to become stronger and higher. At the highest pitch, the rumbles begin to sink until reaching silence. This may continue for half an hour.
1. Editors. The World Book Encyclopedia. World Book-Childcraft International, Inc: Chicago. 1990
2. Payne, Katherine. National Geographic: "Elephant Talk." National Geographic: USA. August 1989 issue. pps 264-277
Nature: Echo of the Elephants: The Next Generation
Every great family is headed by a commanding leader, and Echo's clan is no exception.
Elephant Research in Bioacoustics
In 1984, a hunch of Katy (Katharine B.) Payne, Bioacoustics Research Associate, led to the discovery that elephants use infrasound.