Indeed, some of these animals are sometimes presented as a mystery of nature. There may be a mystery there, but in fact, Nature is so amazing that we will find fantastic things on our Planet for a long time to come.
And here is a list of animals that for many should not exist according to the laws of science.
Giraffe
What's wrong
The existence of a giraffe is nonsense, since even their ten-kilogram heart is not able to raise a column of blood to a height of three meters to the head due to too high pressure, which at the same time should rupture the vessels of the neck. The giraffe cannot bend over: due to the rush of blood to the head, fainting is inevitable. The pressure at the giraffe's legs is about 400 mm Hg. Art. For people, much lower values are fatal, and the pressure in the vessels of our legs does not exceed 90 mm Hg. Art.
Actually
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Although giraffes have a huge heart, relative to body size, it turns out to be quite average. Only in 2016 did scientists find out that the force required to lift blood is created due to the unusual structure of the ventricles and their reinforced walls. Earlier it was shown that the vessels of the neck do not rupture due to their extreme elasticity, and the vessels in the legs, on the contrary, resemble a fortress - their walls are so thickened. In addition, the vessels can contract very strongly to resist external pressure. And blood does not rush to the head when the giraffe bends down, as it accumulates in the veins running along the neck.
Tardigrades / Tardigrada
What's wrong
Having been outside the ISS, in a deep vacuum and space cold, the tardigrades survived, and then gave birth to fertile offspring. These creatures withstand a wide spectrum of radiation, doses of which are a thousand times higher than the lethal level for humans, heating up to 150 ° C and a pressure of 6,000 atmospheres (normal pressure at the surface is 1 atmosphere).
Actually
Finding themselves in extreme conditions, tardigrades fall into suspended animation: their metabolism slows down to 0.01% of normal, and the water content in tissues drops to 1% of normal. Tardigrade cells withstand dehydration thanks to special sugars and proteins that take on adverse effects. The DNA of tiny animals is protected from radiation by unique proteins of the dsup family, which “envelop” nucleic acids, preventing radiation from reaching genes. These same proteins protect the DNA of tardigrades from damage by strong oxidants like hydrogen peroxide.
Bumblebee
What's wrong
Relatively small wings cannot develop enough lift to support a heavy bumblebee. The first to notice this fact in 1934 was the French entomologist Antoine Magnan. The researcher was preparing for publication his textbook entitled "Flight of insects", and he needed to calculate the characteristics of the flight of the bumblebee. Magnan entrusted the calculations to an assistant engineer, André Saint-Lagu. He, applying the then-known principles of aerodynamics, unequivocally concluded that a bumblebee cannot fly.
Actually
The laws of physics do not prevent bumblebees from flying, just the principles of flight of insects are not at all the same as those used in the design of aircraft. Unlike aircraft wings, bumblebee wings bend when flapping, creating mini-vortices that lift insects up both when flapping and lowering the wings.
Kangaroo
What's wrong
In one jump, kangaroos can overcome up to nine meters, and they can jump for hours. Calculations show that such jumping ability requires at least 10 times more energy than animals get from food.
Actually
Elastic tendons in the hind legs store up to 70% of the energy for a jump. In addition, the task of pushing the body off the ground is greatly facilitated by compensatory movements of various parts of the kangaroo's body, primarily the tail and head. Simple calculations that imply that a kangaroo is like a sack of potatoes that needs to be lifted and lowered to the ground does not include all of these factors.
Archaea / Thermococcus gammatolerans
What's wrong
These bacteria-like creatures carry a radiation dose of 30,000 gray. A person dies after receiving only 5 gray: radiation of such intensity tears DNA into shreds. In addition, T. gammatolerans thrive in boiling water: in the hydrothermal vents, where they were discovered in 2003, the temperature reaches 100 ° C.
Actually
How T. gammatolerans withstand deadly radiation is unclear. Microorganisms repair DNA through highly active nucleic acid "repair" systems. But they are not enough to withstand a dose of 30,000 gray, so researchers are actively studying T. gammatolerans: it is possible that their methods of protection can be used to "repair" DNA damage in humans.
Hummingbird
What's wrong
If the car was traveling at the speed of a hummingbird (relative to its size), it would develop a crazy 2090 km / h - 1.7 times faster than the speed of sound! In a second, the hummingbird moves 380 times its body length. A fighter plane covers a distance 38 times its own length in the same time. To accelerate this way, the birds have to do up to 80 strokes per second. In this case, the "flight efficiency" of the wing muscles does not exceed 20%, and the rest of the energy is dissipated in the form of heat. Given that hummingbirds live in hot climates, and feathers prevent heat from escaping into the environment, birds must heat up to temperatures incompatible with life.
Actually
Hummingbird heat removal has long been a mystery. But in 2016, researchers using highly sensitive infrared video cameras were able to record exactly how birds cool in flight. It turned out that heat is removed through several special zones: around the eyes, on the legs, under the wings and on the stomach. The temperature of these areas is on average 8 ° C higher than the ambient temperature, and depending on the flight speed, the hummingbird organism "chooses" through which zones and with what intensity to get rid of excess degrees. That is, the secret of hummingbirds is in the jewelry distribution of heat-dissipating zones and their finest regulation.