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On the morning of April 19, in Ningbo, Zhejiang, a sperm whale about 20 meters long ran aground in the waters of Shipu, Xiangshan, Zhejiang.
After the whale ran aground, five local boats were dispatched to rescue.
However, due to the large size of the whales, the first round of shallow shallowing plan jointly organized by fishery law enforcement vessels and fishing vessels failed.
After the tide rose, a second round of rescue was organized... At around 5:20 on the morning of the 20th, the stranded sperm whale that successfully escaped the trap finally returned home.
□ tadpole
Whales, such huge and magical creatures, were born in the sea, grew up in the sea, and fell into the sea.
Some people say that "whale fall" is the last way for whales to embrace the sea. "One whale falls, all things are born." After the whale's body falls into the seabed, it can provide a source of original energy and support the survival of other huge biological groups.
However, not all whales are returned to the sea, and many are stranded on beaches.
Search for the "whale stranding" incident on Baidu, and you will find that there are not many such incidents. The related search results can be as high as 1.38 million, which is really distressing.
Why do whales never get lost in the vast sea, but are always easily stranded?
frequently stranded
It happened for a reason
There are many reasons for whale strandings.
○ Topography
Whale strandings mostly occur on gently sloping coasts. Therefore, some scholars believe that whale strandings may be related to local coastal topography and meteorological conditions.
They believe that here on the gently sloping coast, the ultrasonic signals emitted by the whales may be distorted, causing the whales to not correctly detect the position of the deep water and lose their way.
However, studies have shown that the gently sloping coast does not cause confusion in the echo signal, and the topographic theory lacks evidence.
○ Geomagnetism
An Argentine scholar analyzed the mass stranding of 300 whales off the coast of the Malvinas Islands in 1997. He believes that the reason for these strandings is related to sunspot activity.
At the time, intense sunspot activity caused anomalies in the geomagnetic field, which likely interfered with the whale's echolocation system and made positioning errors.
Some scientists have found that the geomagnetic field is weak in many places where whale stranding occurs, and the abnormal magnetic field may indeed cause the whale to swim in the wrong direction, resulting in stranding.
○Disease theory
Zoologists have found a lot of parasites in the ears of a group of whales swimming backwards, so they think that the echolocation system of the whales may be damaged by the parasites in the ear, making it unable to locate properly.
In addition, an autopsy of the stranded whale carcass revealed lesions in the whale's organs.
○Sonar Interference Theory
This view holds that the sound waves and underwater explosion noises emitted by the sonar and echo controllers of warships can disrupt the whale's echolocation system, causing the whale to strand.
○Guide theory
Some people think that whales are social animals. When foraging and other activities, there is usually a member of the "lead whale". When it accidentally washes up on the beach, it may wash up with other members on the beach.
○ Feeding Theory
The idea is that whale strandings are related to their feeding habits.
When fish or squid swim near the coast or spawn near the coast, the whales will also follow, and they forget to return in time due to their gluttony, resulting in stranding after low tide.
○ Atavism
Atavism believes that the ancestors of whales were mammals that lived on land. In the long evolutionary process, an intermediate type of amphibious appeared. When they encountered danger in the water, they would flee to land and form an instinct.
The stranding of whales may have been out of an instinct to return to land for safety.
○Poisoning theory
Some scientists and environmentalists believe that environmental pollution is the cause of whale strandings. Pollutants poison the whales, which in turn lose their ability to move normally, leading to accidental strandings.
When the Japanese scholar Iwata Hisato dissected the dead whale carcass, he found that it contained high concentrations of tributyltin, triphenyltin and other toxic substances (these toxic substances mostly came from the bottom paint).
These substances are likely to cause damage to the whale's nervous system, disorienting the whale.
In addition, whales may swallow indigestible marine debris (such as plastic bags), and the accumulation of debris in their bodies causes them to struggle until they reach the shallows.
So far, the real cause of whale strandings has not been determined.
But it has to be admitted that human activities have a great impact on the survival of whales.
Why do stranded whales die so easily?
Whales are mammals that breathe by lungs, so why do they die after stranding?
Let's start by understanding how whales breathe.
The ancestors of cetaceans returned to the ocean about 53 million years ago. During the evolution, some adaptive changes occurred in the shape and physiological structure.
When a whale dives in the deep sea, the lungs are subjected to enormous pressure, the alveoli are compressed, and the gas enters the large windpipe.
As a result, the lungs perform little or no gas exchange and do not store air.
Whales breathing with lungs have formed a hypoxic adaptation mechanism due to long-term diving, and 80%-90% of their oxygen is stored in the blood and muscles.
When the oxygen in their bodies is depleted, they surface and breathe through the nostrils above their heads for gas exchange.
During gas exchange, they exhale the gas from the lungs first, thus creating a water column.
So why do whales die after stranding?
All because whales are so huge.
The largest whale is more than 30 meters long and weighs nearly 190 tons.
When they are in the ocean, the buoyancy of the sea water supports their body weight. Once they swim to the beach and lose the buoyancy of the sea water, the weight of the whole body will concentrate on the contact surface, compressing the bones and internal organs, resulting in broken bones and internal organs. Breathe and eventually die.
Some smaller whales can struggle to survive for longer periods of time when they are stranded, which may indirectly suggest that weight is a major cause of whale deaths.
But if left untreated, they can still die from organ failure, suffocation or infection due to their excess weight and hyperthermia from sun exposure.
However, if you find a whale stranded on the beach, don't go to the rescue without professional rescue knowledge.
On the one hand, violent drag rescue may cause more harm to whales, on the other hand, frightened whales may cause harm to people; in addition, whales that have died for a long time have microorganisms in their bodies to decompose, which will produce a lot of gas, gas Accumulation can cause the corpse to explode, and its power should not be underestimated.
Such a huge creature is so fragile.
I hope that every whale can swim freely in the sea, be born in the sea, and fall into the sea.
(Source tadpole stave)