All Washed Up: The Phenomenon of Stranding
by In October 1986 a beach in Reykjavik, Iceland, was the scene of an apparent massacre: 148 pilot whales lay dead on the shore. They died because in following their leader, or pilot, they swam onto the beach could or would not escape back into the sea.
All Washed Up: The Phenomenon of Stranding
By Mr Ghaz, May 16, 2010
All Washed Up: The Phenomenon of Stranding
In October 1986 a beach in Reykjavik, Iceland, was the scene of an apparent massacre: 148 pilot whales lay dead on the shore. They died because in following their leader, or pilot, they swam onto the beach could or would not escape back into the sea.
What in mysterious about this destructive behavior is that it has often happened before. In September 1975 more than 200 pilot whales were found on the beach at Bonavista Bay, Newfoundland. In January 1983, 87 killer whales stranded themselves on a beach in eastern Victoria, Australia. And from 1963 to 1980 at least 169 whales of different species stranded themselves on the coast of southern Africa alone.
Stranding, or beaching, is common behavior in whales and dolphins worldwide, and scientists are struggling to explain why these otherwise intelligent mammals, either knowingly or accidentally, kill themselves in this manner.
The Greek philosopher Aristotle, writing in the fourth century B.C., mentioned the stranding of dolphins but offered no opinion as to why they might do it. In the second century A.D. the poet Oppian of Corycus suggested that dolphins did this “in the hopes men find them and … stay to fling a mound of shingle o’er them.” Since then more scientific theories have been advanced, but no single one has been proved.
Mass Suicide or Primitive Insecurity?
The most popular explanation among laymen is that the whales are committing suicide intentionally: when attempts have been made to head them off, or return them to deeper water, they still struggle to suicide.
Research from the University of Georgia suggests that stranding may be a primitive to stress, and that the whales follow an instinct to return to the security of the land from which, as mammals, they originally came. There is little concrete evidence to support this theory, however, and other scientists see stranding as an example of social behavior; they believe that it occurs when one whale becomes ill and is followed ashore by concerned members of the group.
Disorienting Theories
Explanation of stranding are extremely varied and numerous. Some blame environmental factors, such as high tides and electrical storms; others make much of the ability of whales to navigate and communicate with each other by means of sonar, a highly sensitive system of beaming sounds and interpreting echoes. For example, it has been suggested that certain beaches with very gentle slopes do not return a true echo, and so the whales become disoriented. Similar disorientation may result from ear infections that cause the sonar system to malfunction.
British scientists at Cambridge University believe they may have found the solution: that whale may strand when they have become confused by abrupt variations in the earth’s magnetism. Although the earth’s magnetic field varies considerably in strength from place to place, lines of equal magnetic strength run for many miles under the sea.
Whales sense these lines easily and tend to follow their direction. The magnetic lines usually follow the coastline, but occasionally they run onto the shore, confusing the whales.
This theory has been borne out by cases of stranding in Britain, which have always occurred where the magnetic line runs into the land. Unfortunately, few maps of magnetic fields from other parts of the world are available for comparison, and so the theory cannot be adequately tested.
The Guessing Continues
While each of these theories may partially help to explain the reason for stranding, none has proved completely satisfactory. In 1977 the Stranding Workshop was set up by the U.S. Marine Mammal Commission to study the phenomenon. There is clearly no shortage for the commission to explore.
So far we can only guess as to why these creatures sometimes destroy themselves, and the mystery of this puzzling behavior may never be solved.
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Post CommentChristine Ramsay
On May 16, 2010 at 7:49 am
It is sad to see so many of these wonderful creatures in such dire straits. A really interesting read.
Christine
CHAN LEE PENG
On May 16, 2010 at 11:17 pm
It was so sad to see these creatures in this manner..well read and thanks. liked it…:-)