It would seem that it could be easier than defining a concept that we have known since school days. Let's try.
So, warm-blooded animals are those representatives of the fauna who have warm blood. So what? You have to agree that it turned out to be some kind of tautology that does not explain this scientific term at all.
Will have to delve into biology.
What animals are warm-blooded? We give a scientific definition to the concept
In simple and understandable language, such animals are those whose bodies produce heat by burning food. By the way, such energy is also generated due to the physical activity and trembling of animals.
Scientists have found that warm-blooded animals are exclusively mammals and birds. Amphibians and reptiles due to certain physiological characteristics cannot be attributed to them.
It should be noted that, despite the changing seasons, the onset of severe colds or exhausting heat, the body temperature of this category never changes. Why is this happening?
The fact is that basically all warm-blooded people have the so-called brown fat, which is located under the skin in the neck, back and chest. Its layer, as well as fur, wool and feathers help maintain and retain heat.
The first warm-blooded planet
So, we have already found out that warm-blooded animals are birds and mammals. But what were their ancestors?
Experts believe that the first species appeared in the Cenozoic era. In those days, representatives of the fauna began to feed not only on insects, but also tasted plant foods.
Over time, animals that continued to feed on insects gradually switched to larger foods. That is why their descendants each time were born more and more adapted to this method of nutrition. For example, their claws and fangs began to develop. Modern scholars argue that bears, wolves, tigers and lions later descended from such living things.
The same mammals, which were more willing to eat vegetation, received in the process of development stable and hardy hooves for walking and stronger teeth to make it easier to chew on the plants. Rhinos, elephants, horses and cows later evolved from such animals. Although there were some warm-blooded people who had to completely replace their diet. They adapted to eat only fruits and began to dwell on trees. Thus, the ancestors of the first species of monkeys appeared.
Ways to cool some animals
Even in latitudes with a temperate climate, very dry days come from time to time, when the heat does not allow even us humans to freely move around the city. But we, you see, may well hide from adverse weather in air-conditioned rooms or simply where the walls are so thick that the sun is not able to warm the buildings through. But how are animals saved in such cases?
Mother Nature took care of our smaller brothers. For example, each of us noticed that a dog, if it is hot, sticks out its tongue from its mouth. Why? The fact is that in this way the liquid evaporates and lowers body temperature. And birds have a special breathing system equipped with lung bags. The purpose of such a complex system is not only gas exchange and respiration, but also the release of internal organs from heat in the process of blowing.
In general, it should be noted that if any organisms on the planet can still surprise with their adaptability to the environment, then these are warm-blooded animals. Examples can be given endlessly.
A bird that never freezes
Probably, each of us had to hear about this inhabitant of the harsh southern latitudes. Even children love cartoons about funny and mischievous penguins.
As you know, most of these birds live in Antarctica, in a fairly cold habitat.
Being both on land and in water, of course, cold, these birds do not feel any discomfort at all. How do they do it? The thing is that they have a layer of fat that covers their feathers. It helps to keep warm and has a special water-repellent property.
In addition, very closely spaced hard feathers help them stay warm. They are so close to each other that no winds allow the birds to freeze.
But what about the paws, because they are not covered with feathers? But here the problem is solved: penguin legs have very few vessels and nerves, so they are not in danger of frostbite.
Those. in response to the proposal to end the phrase “Warm-blooded animals - this is ...” it is quite possible to name not only cats, dogs, horses and other animals familiar to us, often found in cities and villages, but also penguins - inhabitants of the coldest places on the planet.
Why does the bear sleep in winter?
Of course, you can deal with the cold and cold in completely different ways. Someone in the process of evolution received warm wool or feathers, generously greased with fat, and there are those who chose a fairly simple way to survive the cold. Which one? Go to sleep! Probably, even children can list which animals (warm-blooded) dream peacefully, while it is snowing outside their shelter, a blizzard rules, and the thermometer rarely rises above zero degrees. Well, of course, hedgehogs, chipmunks, badgers, bears and many others. But today we will focus on clubfoot.
Bears usually eat plant food, and in winter, of course, it can not be found. Due to the fat accumulated during the warm time, these animals hide in their dens and winter there, feeding on their stocks. So there is no need to go outside.
During hibernation, bears do not lead a mobile lifestyle, their activity decreases to zero. Body temperature drops to the level of ambient temperature, breathing slows down, the heart begins to beat not so actively. These processes allow you not to waste energy, they provide an opportunity to calmly survive the bear all winter. Stocks usually last until the first spring days.
An exception
As we noted above, all mammals and birds are warm-blooded animals. But there is one animal that literally refused this lifestyle and became cold-blooded. This animal is called a naked digger. It is actually amazing and unique, because it combines the opposite physiological features.
Purely theoretically, a naked mole rat can be compared to a rat or a hamster, but on his body you can count no more than a hundred hairs, which is why he is called naked. And the digger, obviously, because he builds houses and lives underground.
By the way, underground there is a rather high concentration of carbon dioxide and a considerable amount of water. All this combined turns into carbonic acid, from which any animal will experience an unpleasant sensation.
But here the digger shines with its uniqueness. It would seem that due to the lack of fur this animal is very vulnerable, but its skin does not react to acid burns in any way, and all because the digger simply got rid of sensitive nerve endings.