The end of November was darkened by sad news from distant Australia. There, about 150 whales were killed off the west coast of Tasmania. The bodies of whales were accidentally discovered by a holder of a marine plantation 200 kilometers west of the city of Hobart. He was stunned by what he saw and reported the incident to the authorities. They tried to save the animals, but most of them were injured after being hit by stones
This type of whale is called black dolphins. Their scientific name is grinda (Globicephala melas). The weight of an adult reaches 3.5 tons, and the length sometimes exceeds seven meters.
Such tragic cases occur with enviable consistency, but scientists still cannot name with certainty the exact reason for this behavior of animals. But there are several versions explaining such a strange, suicidal behavior of whales.
The first version. The military is to blame for everything
British scientists argue that the sound signals sent by the echo sounders of warships are the cause of the death of whales and dolphins. For example, during the NATO naval maneuvers near the Canary archipelago, 15 whales were thrown onto the coast of Fuerteventura and Lanzarote, of which only three animals were saved. Experts believe that radiation from acoustic systems alters the behavior of dolphins and whales. Animals begin to rise too quickly to the surface, which leads to the development of decompression sickness.
For reference
Decompression sickness, or decompression sickness, in abbreviated form - DCS (in the jargon of submariners - caisson) is a disease that occurs mainly due to a rapid, compared with the desaturation time, decrease in the pressure of the inhaled gas mixture, as a result of which gases (nitrogen, helium, hydrogen - depending on the respiratory mixture), dissolved in the blood and tissues of the body, begin to be released in the form of bubbles into the blood of the victim and destroy the walls of cells and blood vessels, block blood flow. When severe, decompression sickness can lead to paralysis or death. (Wikipedia).
Greenpeace experts say that "the waves emanating from the radar installations cause unbearable pain in the ears of whales, which forces them to be washed ashore." British scientists prove their point of view by the fact that in 1989, also during naval maneuvers near the Canary Islands, 24 whales were thrown ashore. Two years ago, under the same circumstances, three whales washed ashore on the Portuguese island of Madeira.
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Second version. Magnetic
However, cases of whales being discarded were known long before the first submarine was launched. It turns out that at that time the behavior of the animals was influenced not by the echo sounders of the ships, but by some other factors. A number of scientists believe that this factor is the magnetic field. The fact is that whales use the Earth's magnetic field for amazingly accurate underwater navigation when traveling across the oceans. And it is very strongly influenced by external factors - for example, magnetic storms on the Sun influence it. It is also likely that the gradually changing shape of the coast does not match the ancient map of whale migration. Lines of geomagnetic variation (magnetic troughs) usually run parallel to the coast and may be distorted by an island or geological outcrop on the coast. Whales using coastal magnetic contours to navigate in places like theselose their bearings and suddenly find themselves in dangerous shallow water or are thrown aground.
It is interesting
Neurophysiologists believe that the dolphin's brain is on the same level as the human brain and is potentially capable of the same as the human brain. Such an organ, according to American physiologist John Lilly, provides dolphins with verbal communication with each other and in the future will allow them to meaningfully talk with humans (basik.ru).
Third version. The leader and mutual assistance are to blame for everything
Mental disorder of the leader is also cited as the cause of suicide, followed blindly by the herd. Animals trust the leader and follow him to certain death. There is also a hypothesis that whales become victims of a sense of mutual assistance. When one of the animals is on land or shallow water, it gives alarm signals, and relatives rush to help. As a result, the "rescuers" themselves are thrown ashore and also begin to ask for help.
Version four. Self-destruction
There is a version that the mass death of animals is a way of self-regulation of the whale population. When the density of the "population" of cetaceans exceeds a certain value, supporters of this theory believe, animals simply self-destruct. Biologists explain the phenomenon of mass migrations of northern rodents - lemmings in approximately the same way. Lemmings move in a continuous stream, without disassembling roads, and die by the thousands in bodies of water caught in the way. As a result, the livestock of animals remains within the limits set by nature.
Also, a lack of food is put forward as hypotheses, as a result of which whales swim in shallow water, and human pollution of the World Ocean: in some dead animals, the respiratory organs were clogged with oil products or plastic wrap. But the first does not explain why even those cetaceans that feed on plankton die, and the second cannot explain why those animals die if no harmful effects on the organism were noted.
And yet, there is still no unambiguous reason for the death of cetaceans accepted by the entire scientific world.