How whales can hold breath so long in underwater using their lungs?
As we all know, whales and dolphins are not fish; They are mammals, like humans! Despite living underwater, there are some reasons why they are different from aquatic animals. Whales give birth to their young (not with eggs like fish) and nurse them. They are warm-blooded.
In fact, no event in our nature is out of the norm. There are numerous aquatic and terrestrial animals in the world. Most of these animals use oxygen for respiration. A few low-grade bacteria can survive without oxygen. They cannot tolerate oxygen. Again, advanced animals have special organs for receiving oxygen from the environment. In the aquatic environment, the organ is named gills (below the gill cover of fishes) and in the terrestrial environment, it is called the lung.
The gills extract dissolved oxygen from the water, while the lungs synthesize oxygen from the air. However, the most striking difference between whales, and dolphins with fishes is that they do not have gills, but have lungs. This means they cannot breathe using oxygen dissolved in water. So how do they breathe? The simple answer is they can only breathe when the lungs work properly. So every time they want to take the air, they have to break the surface of the water and peer into the ocean of air. They are not amphibians though they peer into the sea of air. You can't mark them as amphibians. For example, let's think about a frog. The main reason for their being amphibious is that they have gills in the early stage of life, and when they become full-fledged, it turns into a lung. So the attraction of frogs to water is natural.
The evolution of whales
Like whales and dolphins, and some other marine animals such as porpoises, walruses, and seals, they belong to a group of mammals called Cetaceans. Scientists believe that millions of years ago, the evolutionary ancestors of whales walked the Earth, just as we do today. However, over the years, they gradually move to the sea, adopt a 'water' lifestyle and start spending time here permanently. This is why marine animals (whales, dolphins, etc.) appear to be fish but actually have no right to be classified as fish.
Whales and dolphins do not have gills
We probably learned about the different organs of fish in high school. Especially notable among them are Gills. Gills are special organs of fish that help the fish synthesize dissolved oxygen from the water and breathe underwater. As we already know, dolphins and whales do not have gills. In contrast, dolphins and whales have a set of lungs like ours, which means they can't breathe underwater. Because of this biological need, these species are often seen surfacing to get some fresh air. Dolphins, however, usually only run out of oxygen after a few minutes. Head up to get air through the water surfaces. Dolphin's breathing is shallow. So how do they sleep? Do they peer into the sea of air while sleeping? Dolphins have a unique character to adapt to water. Half of their brain is awake while sleeping. And the other half sleeps. So they don't die in their bedroom. But whales can hold their breath underwater for about two hours. What a surprise! Can you imagine?
How can whales hold their breath underwater for so long?
1. Efficient respiratory system
Some special components, organs, and factors in the physical system of whales bring out this exceptionality. To begin with, whales have a very efficient respiratory system, which allows them to sustain the effect of a single breath for the longest time. Interestingly, we humans breathe 12 to 20 times per minute while resting and absorb only 5% oxygen in each breath. But on the contrary, whales have to thank for their highly efficient respiratory system because they absorb 90% of the oxygen in each breath. So a whale needs a lot more oxygen per breath than a human.
2. Conservation of energy
Whales do several things to fully utilize a breath. First, it lowers his heart rate. Secondly, it reduces the blood flow rate to various organs like the brain, muscles, and heart. But the interesting thing is that doing these things does not change the blood pressure of the animal. Thus the energy is conserved and distributed slowly.
2. Myoglobin
The biggest advantage for whales is myoglobin, a protein found in the muscles of most mammals. Myoglobin's primary function is to bond with oxygen molecules, or more simply, to store excess oxygen. Therefore, when you hold your breath for a short period, it is myoglobin that supplies your body with oxygen. Since aquatic mammals spend most of their time underwater, their muscles naturally contain more myoglobin than land-based mammals like us. Even among marine mammals, whales Myoglobin has a special property. A study published in 2013 found that whale muscles contain the positively charged protein myoglobin. This special feature helps whales pack more myoglobin into their muscles than other mammals. Myoglobin proteins are normally bound together, but when they have the same charge, they then repel each other (like the same poles of a magnet repel each other) and these protein molecules diffuse faster, increasing their efficiency. It is the feature that enables a whale to breathe' for much longer than other mammals.
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