It would seem that it could be easier than to define a concept that we have known since school. Let's try.
So, warm-blooded animals are those representatives of the fauna that have warm blood. So what? Agree, it turned out to be some kind of tautology that does not explain this scientific term at all.
Got to go deeper into biology.
Which animals are warm-blooded? We give a scientific definition of the concept
In simple and understandable terms, these animals are those whose bodies produce heat by burning food. By the way, this energy is also generated due to the physical activity and trembling of animals.
Scientists have established that warm-blooded animals are exclusively mammals and birds. Amphibians and reptiles cannot be attributed to them due to certain physiological characteristics.
It should be noted that, despite the change of seasons, the onset of severe cold or exhausting heat, the body temperature of this category never changes. Why is this happening?
The fact is that basically all warm-blooded animals have the so-called brown fat, whichlocated under the skin in the neck, back and chest. Its layer, as well as fur, wool and feathers, help keep you warm.
The first warm-blooded animals on the planet
So, we have already found out that warm-blooded animals are birds and mammals. But what were their ancestors like?
Specialists believe that the first species appeared in the Cenozoic era. In those days, representatives of the fauna began to eat not only insects, but also tried plant foods.
Over time, animals that continued to eat insects gradually switched to larger foods. That is why their descendants each time were born more and more adapted to this way of eating. For example, they began to develop claws and fangs. Modern scientists claim that bears, wolves, tigers and lions later descended from similar living creatures.
The same mammals that were more likely to feed on vegetation developed stable and hardy hooves for walking and stronger teeth to make it easier to chew plants. Rhinos, elephants, horses and cows later evolved from such animals. Although there were some warm-blooded who had to completely change their diet. They adapted to eat only fruits and began to live on trees. Thus, the ancestors of the first species of monkeys appeared.
Ways to cool some animals
Even in latitudes with a temperate climate, from time to time very dry days come when the heat does not allow freemove around the city even to us humans. 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 herself took care of our little brothers. For example, each of us noticed that a dog, if it is hot, sticks its tongue out of its mouth. Why? The fact is that in this way the liquid evaporates and lowers the body temperature. And birds have a special respiratory system equipped with lung sacs. 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 also surprise with their adaptability to the environment, then these are warm-blooded animals. Examples are endless.
The bird that never freezes
Probably, each of us has heard about this inhabitant of the harsh southern latitudes. Even kids love cartoons about funny and mischievous penguins.
As you know, most of these birds live in Antarctica, in a rather cold habitat.
Being both on land and in water, of course, cold, these birds do not feel discomfort at all. How do they do it? The thing is that they have a layer of fat that covers the feathers. It helps keep you warm and has a special water-repellent property.
In addition, very closely spaced hard feathers help them to keep 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 even here the problem is solved: the legs of penguins have very few vessels and nerves, so they are not in danger of frostbite.
I.e. in response to the proposal to end the phrase “Warm-blooded animals are…”, it is quite possible to name not only cats, dogs, horses and other living creatures 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 cold and cold in completely different ways. Someone in the process of evolution received warm wool or feathers, generously greased, and there are those who chose a fairly simple way to survive the cold. Which one? Hibernate! Probably, even children can list which animals (warm-blooded) dream peacefully while it snows outside their shelter, a blizzard reigns, and the thermometer rarely rises above zero degrees. Well, of course, hedgehogs, chipmunks, badgers, bears and many others. But today we will talk about clubfoot.
Bears usually eat plant food, and in winter it is certainly not found. Thanks to the fat accumulated during the warm time, these animals hide in their dens and spend the winter there, eating from their reserves. This eliminates the need to go outside.
During hibernation, bears do not lead a moving imagelife, their activity is reduced to zero. Body temperature drops to the level of ambient air temperature, breathing slows down, the heart begins to beat less actively. These processes allow you not to waste energy, they make it possible for the bear to survive the whole winter calmly. Stocks are usually enough until the first days of spring.
Exception to rule
As we noted above, all mammals and birds are warm-blooded animals. But there is one animal that literally abandoned this way of life and became cold-blooded. This animal is called a naked mole rat. It is actually amazing and unique, because it combines opposite physiological features.
Purely theoretically, a naked mole rat can be compared to a rat or a hamster, but you can count no more than a hundred hairs on his body, which is why he is called naked. A digger, obviously, because he builds houses and lives underground.
By the way, there is a rather high concentration of carbon dioxide underground and a considerable amount of water. All this combined turns into carbonic acid, which will give any animal an unpleasant sensation.
But even here the digger shines with his uniqueness. It would seem that due to the lack of fur, this animal is very vulnerable, but its skin does not react in any way to acid burns, and all because the digger simply got rid of sensitive nerve endings.
