It would seem that could be easier than to define the concept, which we know from the school.Let's try.
So, warm-blooded animals - these are the fauna that have warm blood.So what?Agree turned some tautology that does not explain the scientific term.
'll have to delve into the biology.
What animals are warm-blooded?We give a scientific definition of
In simple and understandable language, such animals are called those whose bodies produce heat by burning food.By the way, this energy is produced also through physical activity and shivering animals.
Scientists have found that warm-blooded animals - it's only mammals and birds.Amphibians and reptiles because of certain physiological features can not be attributed to them.
It should be noted that, despite the change of seasons, the offensive fierce cold or the exhausting heat, body temperature, this category has never changed.Why is this happening?
fact, that basically all warm-blooded a so-called brown fat, which is located under the skin in the
first warm-blooded planet
So, we have found that warm-blooded animals - a bird and mammals.But what were their ancestors?
Experts believe that the first species appeared in the Cenozoic era.In those days, fauna began to eat not only insects, but also to try vegetarian food.
Over time, animals that eat insects continued to move gradually to a larger meal.That is why their descendants are born every time more and more attuned to this way of eating.For example, they began to develop claws and fangs.Modern scholars argue that from these beings occurred later, bears, wolves, tigers and lions.
Those mammals are more likely to eat the vegetation, obtained in the process of developing sustainable and durable hooves for walking and stronger teeth, to make it easier to chew plants.From these animals later took rhinos, elephants, horses and cows.Although there were some warm-blooded, which had to completely replace your diet.They have adapted to eat only fruits and began to dwell in the trees.Thus there were the ancestors of the first species of monkeys.
methods of cooling some animals
Even in temperate latitudes at times come very dry days when the heat does not allow to move freely around the city, even for us humans.But we agree that it is able to hide from the bad weather in rooms with air conditioning, or simply where the walls are so thick that the sun is unable to warm up through the building.But what saved the animals in such cases?
About our smaller brothers took care of Mother Nature herself.For example, each of us noticed that the dog, if it's hot, his tongue out of his mouth.Why is that?The fact that the liquid thus vaporizes and reduces the temperature of the body.But birds have a special system of breathing, pulmonary equipped bags.The purpose of such a complex system - not only gas exchange and breathing, but also the release of the internal organs from the heat during the blowing.
In general, it should be noted that if any organisms on the planet, and may even surprise its adaptability to the surrounding environment, it is warm-blooded animals.Examples can lead indefinitely.
bird that never freezes
Perhaps this harsh inhabitant of southern latitudes had to hear every one of us.Even children love cartoons about the fun and mischievous penguins.
As you know, the majority of these birds live in Antarctica, in a rather cold environment.
Being both on land and in water, of course, the cold, the birds did not feel discomfort.How did they do it?The thing is that they have a layer of fat, which is covered with feathers.It helps to retain heat and has a special water-repellent properties.
In addition, they help retain heat very closely spaced rigid feathers.They are in close contact with each other, that no wind do not give the birds freeze.
But what about the legs, because they are not covered with feathers?But here the problem is solved: the penguin's feet are very small blood vessels and nerves, so they are not threatened frostbite.That
in response to a proposal to end the phrase "warm-blooded animals - is ..." can be called not only our usual cats, dogs, horses and other animals are often found in cities and villages, and the penguins - the inhabitants of the coldest places on the planet.
Why bear sleeping in the winter?
course, with chills and chill can fight very differently.Someone in the process of evolution has received a warm fur or feathers, generously greased and there are also those who chose a fairly simple way to survive the cold.Which one?Hibernate!Perhaps even children can list what animals (warm-blooded) peacefully dreaming while outside their shelter snowing, snowstorm reigns, and the thermometer rarely rises above zero degrees.Well, of course, hedgehogs, chipmunks, badgers, bears and many others.But today we will just about clumsy.
bears normally feed on plant foods, but in winter it is definitely not find.Due to the accumulated time for the warm fat, these animals are hiding in their dens and hibernate there, eating their reserves.So there is no need to go outside.
During hibernation, bears do not lead sedentary lives, their activity is reduced to zero.Body temperature drops to ambient temperature, breathing slows, the heart begins to beat not so active.These processes make it possible not to waste energy, they provide the opportunity to quietly endure bear all the winter.Stocks usually lasts until the first spring days.
exception to the rule
As we mentioned above, all mammals and birds - warm-blooded animals.But there is a small animal that literally gave up this way of life and became a cold-blooded.It is called the animal naked navvy.It is really amazing and unique, because it combines the opposite physiological features.
Theoretically mole rat can be compared to a rat or hamster, but his body can not count more than a hundred hairs, so it is called naked.A digger, obviously, because it builds houses and lives underground.
way, underground rather high concentration of carbon dioxide and a considerable amount of water.All this combined is converted into carbonic acid, from which the animal will experience any discomfort.
But here digger shines with its uniqueness.It would seem that because of the lack of this small animal fur is very vulnerable, but his skin does not react to acid burns, and all because digger simply got rid of sensitive nerve endings.