I don't know when it began, there is a story circulating on the Internet: "Whales are drowned by water because they breathe with their lungs."
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Sprinkled with thousands of words, from the birth of the whale to the death, it seems to be erudite, but in fact, the starting point is wrong, and how to argue will not be correct.
So how do whales die? Why is the death of a whale great? Let's move on to the next look!
Whales are mammals and do not belong to fish
Although the whale looks like a fish and has the word "fish" in its name, it also lives in the water, but it is not a fish, but a mammal, just like a bat like a bird but not a bird.
The key characteristics of whales are consistent with those of mammals.
First, whales have no scales on the outside, but fish basically have them.
So why don't whales have scales on their surface? There are two hypotheses here, namely scientific inferences that have not been proven.
The first, the even-ungulate hypothesis, is that the whale evolved from an ancient type of even-ungulate, but which one it refers to is not stated, because it cannot be judged only from fossils.
The second, the hippo evolution hypothesis, is that whales evolved from ancient hippos, which were measured by DNA, which showed that hippos and whales were genetically very similar, hence the hypothesis.
These two hypotheses are used to explain why whales do not have scales.
Second, whales breathe by their lungs, while fish breathe by gills.
Fish breathe on their gills, so they must stay in the water, and they will soon suffocate and die when they leave the water.
Whales breathe through their lungs, so every once in a while, they surface for air exchange. We see small splashes of water spewed by whales, and that is the whale breathing.
Third, whales are thermostatic animals, and fish are thermostatic animals.
The whale's body temperature remains constant at thirty-five or thirty-six degrees. The fish is a warming animal, and the temperature of its body changes according to the change of ambient temperature.
Fourth, whales are born and fish are egg-born
Whales are fetal, and small whales need to eat breast milk for a year to mature, while fish are oviparous, and broodstock will not breastfeed small fish.
Fifth, whales and fish swim differently.
When the fish swims, its tail swings from side to side. Whales are different, their tails are swinging up and down.
Through the above five characteristics, we can easily judge that whales are mammals, not fish. Weird, huh?
So a mammal, living in water and breathing with its lungs, will it drown? The answer is "basically no".
Why whales don't drown
In daily life, we will hear and even see the news of whale deaths, what whales have run aground, whales have been killed, etc., but have you heard or seen whales drown?
That's because in the billions of years of biological evolution, all kinds of animals have become extremely adapted to the environment, and those who do not adapt to the environment have been eliminated.
Whales are more suitable for breathing with their lungs:
All animals need oxygen, but they get it differently. Land animals only need to breathe oxygen in the air, and the oxygen content in the water is low, so fish have evolved gills and breathe with gills.
There is also a more special one, it lives in the water, there is no gills, can only breathe with the lungs, that is, whales. Because the oxygen content in water is only between 4.59 ‰ and 8.72 ‰, it is far less than the oxygen content of 21% of the air.
Breathing air allows whales to get dozens of times more oxygen, and it's clear that breathing with lungs is a more efficient way to breathe, and whales need this oxygen to boost their metabolic rate because they are thermostatic animals.
In addition, the size of the whale is very large, the blue whale can reach 200 tons, if you breathe with the gills, it is impossible to meet the needs of the body, and even the insulation can not be done.
Breathing with lungs was something their ancestors had evolved over hundreds of millions of years, whales have no reason to abandon their lungs, and all living things in nature are efficient, and with lungs they naturally won't make a gill again.
Whales can live underwater for long periods of time:
There are many types of whales, blue whales, baleen whales, killer whales, sperm whales, big winged whales, right whales, gray whales, etc., but if you want to say which whale holds its breath the longest, it is the sperm whale.
Sperm whales are the champion diving in whales. It can dive to a maximum depth of 3000 meters and hold its breath for up to 138 minutes. This is enough for the whale to live in the sea without drowning.
Whales hold their breath for a long time, also because their lungs are so large that they can store a lot of oxygen for breathing underwater.
When the whale takes a deep breath on the surface of the water and dives, the pressure on the body gradually increases, the lungs are squeezed, and the gas in the alveoli is pressed into the trachea.
Therefore, when whales are underwater, there is almost no oxygen in the lungs, which can both reduce the risk of nitrogen spreading into the bloodstream and reduce the risk of small bubbles forming in the blood when rising.
In addition, whales have their own special physiological structure, and their blood volume and hemoglobin are very high.
There is only about 30% of hemoglobin in the human blood, and the blood of whales can exceed 60% of hemoglobin, so when the whale breathes, the blood can absorb a lot of oxygen, and a large amount of oxygen will be stored in the myoglobin of the muscle tissue. Most of the oxygen we inhale will be exhaled together.
Some netizens will ask, will the whale drown when sleeping?
It's an interesting question, whales are also animals, and there are also times when they are tired and resting, in case they oversleep, won't they drown?
In fact, in the evolution of hundreds of millions of years, whales have also evolved a special talent - the left and right brains run independently.
The left and right brains of the whale can run independently, in shifts. When the right brain is tired, it will say to the left brain: I am tired, you come to take over, I go to rest.
In this way, 24 hours a day, there are "people" on duty, which can ensure that the whale will not drown because of oversleeping.
Whales not only do not drown when they sleep, but they do not drown when they eat, even when they are old.
The whale's esophagus and respiratory tract have been completely detached, which can effectively avoid affecting breathing when eating underwater.
The drowning of an elderly whale is nothing more than an internet story.
Many netizens believe that whales need to constantly consume physical energy to surface for air exchange, and elderly whales do not have enough physical energy to surface.
In fact, whales are all expert swimmers, and they can float on the surface of the water and sleep motionless.
Old whales are masters of the art, and they can surface with the help of ocean currents without consuming too much energy.
The ones who are really drowned are the newborn whales, which are not good at swimming, have less fat, and are less buoyant, so they will sink without swinging their tails for a while.
Baby whales appear to be much larger than other fish, but they are still small babies, susceptible to infection and attack, resulting in weakness and eventual drowning when they are unable to surface.
The death of a whale is great
Every creature faces the final outcome when it comes to death, and whales are no exception. Whale deaths have a nice name called "Whale Fall".
"A whale falls on all things." Refers to the fall of a whale in nature, which can form a thriving and large deep-sea biome.
The ocean is the cradle of life, but the distribution of food and light in the ocean is very uneven, and the marine surface is the most diverse and abundant to a depth of 200 meters; Below 200 meters, darkness is the norm, and at a depth of 5,000 meters, the creatures become very single and the number is very small.
Deep-sea creatures have very few sources of food, and the fall of a whale will bring them a lot of food, even more than the amount of food accumulated over a thousand years.
When the whale dies, it gives its body back to its mother, the sea.
Stage 1: Medium and large food animals come on the field
When a blue whale died, half an hour later, the shark smelled its smell, and the hungry shark quickly tore up, and the bright red blood attracted more sharks to feed.
After the shark feast, the scavengers came one after another.
Four months later, hagfish and octopus are still entrenched on the carcasses of blue whales, and onlookers of deep-sea crabs have joined the "war".
The blue whale uses its body to nurture sharks, hagfish, octopuses, sea crabs and other animals.
Stage 2: The mobile scavenger comes
A year later, the giant blue whale turned into a white bone, and more than 90% of the meat was eaten, at which point it welcomed another group of diners — polychaetes, worms, snails, and king-footed insects.
They unscrupulously cleaned the last bit of flesh from the blue whale's body and then left in a dashing manner. It's just that the cleaning time is relatively long, more than 1 year.
The third stage: worms, anaerobic bacteria.
But that's not the end of it. Deep-sea worms coil onto whale bones, penetrate the tentacles deep into the bone marrow, and use bacteria to break down fat and then absorb nutrients.
Anaerobic bacteria have also begun to enter whale bones, breaking down lipids in whale bones while producing hydrogen sulfide, a sulfur-rich environment that provides an energy source for some bacteria.
This stage can last for decades, or even hundreds of years, and it can raise hundreds of tiny animals.
Final stage: The home of many creatures
Finally, the massive whale bone becomes a reef on the ocean floor, where many deep-sea animals make their home, and even corals climb on it.
Whales can fall for decades, providing food and habitat for hundreds of species of creatures, including sharks, hagfish, octopuses, sea crabs, worms, snails, king pods, worms, and anaerobic bacteria.
A whale falls, and everything lives. The death of a whale is cruel, yet beautiful and great.
Write to the end
Do you know how whales die?
Most whale deaths are caused by humans.
Commercial whaling, fishing wires, entanglement of fishing nets, pollution by toxic substances, and boat collisions have caused whales to die before they can grow old.
At the same time, things such as sonar used by human ships interfere with the whales' judgment, causing more and more whales to run aground.
As the largest animal on the earth, because of human activities, this strange animal is less and less, and "a whale falls, all things live." "There are also fewer and fewer poignant stories.
Protecting whales and protecting marine ecology starts with you and me!
I am a science and technology mingcheng, welcome to discuss together.