A miracle happened! The sperm whale returned home! Why do whales get stranded?

Expert of this article: Liu Yadan, former assistant secretary-general/researcher of China Fisheries Society, national chief scientific communication expert

On April 19, the news that #a sperm whale was stranded in the Shipu waters of Xiangshan, Ningbo# attracted much attention. After receiving the clue, the local fishery administration and fishermen quickly organized a rescue.

Image source: CCTV News

After more than 20 hours of relay rescue, the whale arrived at the destination sea area and successfully returned to the sea at around 5:30 am on the 20th under the towing and escort of the fishery administration ship.

Source: People's Daily

This time we were able to successfully rescue the stranded sperm whale, which is not only of great significance to the protection of marine ecology, but also accumulates good experience for the rescue of stranded whales in the future.

So the question is, why do whales get stranded? What difficulties are faced in rescuing stranded whales? What happens when a whale dies on land? Next, we will answer them for you.

What kind of animal is a sperm whale?

Sperm whales, scientifically known as Physeter macrocephalus, can reach a length of 18 meters and weigh more than 50 tons, making them the largest of toothed whales. Although there are many types of whales, their classification is very simple. Those with beards but no teeth are called baleen whales, of which there are 11 species. Those with teeth but no beards are called toothed whales, of which there are more than 70 species. There are more than 80 species of whales in the world, of which more than 30 species live in my country's waters, most of which live in the sea and a few in fresh water.

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The sperm whale has a huge head, which can account for 1/3 of its body. Compared with its big head, its lower jaw is relatively small, and only has teeth in the lower jaw. Its main delicacy is squid. Like other whales, it is not accurate to call sperm whales fish. It should be said that whales are aquatic mammals. They are just becoming more and more fish-like in evolution, but their physiological characteristics such as breathing with lungs, viviparity, and breastfeeding are too similar to those of terrestrial mammals, so much so that some scientists have pointed out that ancient whales may have been amphibians.

Sperm whales are a precious species of whales. The reason why they are precious is that in addition to their unique ability to secrete ambergris in their bodies, their language is also special. The American website Fun Science once talked about "Can humans learn to talk to whales?" It was talking about people's research on the language of sperm whales. They believe that sperm whales are one of the loudest animals on earth, and their communication language may become a mature language.

Why do sperm whales get stranded?

Sperm whales are smart and have great diving abilities. Among mammals, they dive the deepest and for the longest time. So some people ask: "How can such a diving champion get stranded?"

According to measurements by on-site staff, the whale is about 19 meters long and weighs about 70 tons, with obvious scratches on its tail and head. Professor Zhao Shenglong of Zhejiang Ocean University analyzed that the whale was stranded in the shallow sea most likely because it was injured or its life was about to end, and its physical condition was not enough to support its survival in the open sea.

In fact, there are reports of whale stranding and mass suicide every year around the world, and they are sperm whales. In March 2017, there was also one in Daya Bay, Guangdong. When the whale was found, it was already dead, and there was a baby whale in its body.

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Some scientists have also made speculations about the mystery of whale suicide, and these speculations are not without reason. For example: whale stranding may be related to coastal terrain and meteorological conditions; the whale group is stimulated by an unexpected event, causing them to hastily land and become stranded; when there are too many delicacies near the shore, they are greedy and get stranded after the tide recedes; some whales are particularly collectivist, and the whales follow their leaders to swim and eat together, and flee together when they encounter danger; there are also those who talk about the characteristics of the whale's ancestors, believing that whales, once amphibians, are accustomed to escaping to land when they encounter danger in the water, and looking for a safe place to avoid risks.

Most scientists believe that whale stranding is related to the damage of its echolocation system, because whales do not rely on their eyes to determine direction, but rely on their innate high sensitivity of echo ranging. At present, there is more evidence that one is the impact of noise, the second is the parasites in the ear, and the third is environmental pollution. Some researchers also believe that due to the deterioration of the marine environment, chemicals in the water may disturb the whale's senses and cause stranding. Of course, the above speculations about the reasons for whale stranding still need to be explored by researchers.

Will a whale explosion occur if a whale dies on land?

When any organism dies, the bacteria in its body will multiply in large numbers, producing gases that cause the body to swell, and whales are no exception. When it dies, the large number of bacteria in its body, especially in its internal organs, begin to decompose, and some explosive gases, such as methane and ammonia, slowly accumulate in the body.

Generally, whale explosions occur when the body of a whale swells after death and the staff improperly operate the body or deflate it manually. The skin and fat of a whale are very tough, and it takes a certain amount of time for it to explode after death on land. For this reason, when a whale explodes, there will be a "earth-shattering" scene.

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So if a whale dies in the sea, will it not explode?

According to scientific observation data, if a whale dies in the sea, its body will generally sink to the bottom of the sea relatively intact, unless it encounters a group of sharks. Usually, a whale will not be torn apart quickly when it dies in the sea, but there will be some small scavengers that will slowly eat the carrion. It is said that the entire process from the death of a whale to its complete disappearance takes up to 30 years or even longer. During this period, the whale carcasses form a small ecosystem on the seabed, and their death is as meaningful as their life.

How difficult is it to rescue a stranded whale?

1. Tide problem. Whales are too big and too heavy. After being stranded, they lose the buoyancy of seawater, and their internal organs and bones cannot support their weight. In the end, they will suffocate due to respiratory failure. Waiting for high tide is very dangerous. Although the staff will continue to pour seawater on the whales, it often does not solve the problem. If they are dragged back to the sea rashly, their internal organs will rupture, fracture and dislocate, causing more serious damage to their bodies.

Second, they failed to receive timely treatment. Scientists conducted autopsy analysis on individual stranded whales and found that some of them left the water and came ashore because they were sick or injured. Their bodies were too weak to handle the wind and waves, and they were pushed ashore by the current.

3. Sunlight and temperature changes. Stranded sperm whales have been stranded for a long time and have left the water. Their skin is exposed to the sun, and the temperature is obviously higher than in the water. Dehydration, cracking, infection and peeling of the skin often become fatal injuries to stranded whales.

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4. Lack of emergency rescue equipment. In many cases, although rescuers arrived in time, there was a lack of emergency rescue equipment on site. Rescue by manpower alone would take too long, and even if we stayed by the stranded whale all the time, it would be of no avail.

In short, the rescue of stranded whales is very complicated and difficult. It is important to use professional rescue methods and scientific methods to rescue stranded whales.

Under the condition of global warming, the life and habits of various marine creatures will change to varying degrees. We hope that every whale can swim freely in a clean and peaceful sea. We must work together to protect the marine environment and ecology, and don't let these lovely and tenacious lives suffer and cry in the ocean!

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