Scientists do not exclude the possibility that during the era of global glaciation, over the Arctic Ocean, there was a giant ice continent Arctida with unique natural and climatic conditions. Its largest inhabitant was the northern elephant - the mammoth. And curious riddles are associated with the mammoths of Arctida.
UNUSUAL MATERIAL
“During the era of glaciations in the Northern Hemisphere it was much colder than now,” Saveliy Vladimirovich Tormidiaro, a paleogeographer-permafrost scientist, Doctor of Geography, wrote in the article “Arctida As It Is” back in Soviet times. - What should have happened in such conditions with the Arctic Ocean? It began to freeze, and its drifting ice welded into a single motionless plate tens of meters thick.
This gigantic ice land welded the northern continents, and in the center of it a great polar anticyclone was established, much more powerful than the one that now stands in Antarctica. Cold air began to "slide" to the south, but under the influence of the Earth's rotation it moved to the west - this is how … a constant east wind was formed. And in the upper layers of the atmosphere, a so-called reverse suction funnel is created.
And this giant "vacuum cleaner" began to "throw" particles suspended in dry air, distributing them over the ice shell … So Arctida began to be born. The picture turns out, of course, unearthly: a whole supercontinent with an almost Martian climate lies in a huge space. Calculations show that the extreme temperature difference in its center could reach 150-180 degrees."
Endless dry steppes covered Northern Eurasia at that time. Dust clouds swirled over the dry permafrost steppes of Europe, Siberia, and North America. And of course, this dust was carried through the upper layers of the atmosphere into the Arctic and fell there on the sea ice. At first it was just a bloom, but then it began to turn into increasingly thickening layers of loess.
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In summer, from a cloudless sky, the Arctic sun began to shine around the clock, not setting for four months. Temperatures rose sharply, especially on the dark ground. This created ideal conditions for the growth of grasses, because ice lay shallow under the layer of earth, which slightly thawed and moistened the soil of the ice-loess continent - Arctida.
This mainland was able to feed huge herds of large animals: mammoths and woolly rhinos, musk oxen and horses, Arctic bison, saigas, yaks, not to mention countless small animals. It is no coincidence that the entire Arctic is dotted with their bones, including the Arctic sea shelf.
With the onset of a long Arctic winter, when the temperature could drop to minus 100-120 degrees, that is, much lower than at the modern cold pole in Antarctica, small animals migrated away, but mammoths, very possibly, hibernated.
HOW TO WINTER?
The hypothesis that the basis for the adaptation of mammoths to life in the Arctic Circle was hibernation, as hibernation is scientifically called, is from time to time expressed by scientists. Recent finds by Russian paleontologists seem to support this assumption.
It turned out, for example, that mammoths had a highly developed so-called brown adipose tissue, which is characteristic of animals that hibernate. In the area of the withers of a 15-year-old adolescent mammoth found in Taimyr, brown fat formed a whole hump. During hibernation, metabolism slows down, making it impossible to maintain body temperature by contractions of skeletal muscles.
Therefore, in animals hibernating, brown adipose tissue is well developed, which maintains body temperature. Brown fat, whose cells are filled with mitochondria, plays a special role when waking up from hibernation: with the help of the heat it generates, the body temperature rises.
The energy resources accumulated in brown adipose tissue could allow the mammoth to spend the winter in a kind of den, as modern polar bears do, living in approximately the same climatic conditions.
If this is possible for such energetic and large - weighing up to a ton - predators, then it made sense for a leisurely herbivore to spend the most severe winter months in suspended animation.
Another argument in favor of hibernation is the mammoth blood that does not freeze in the cold. The problem of cryogenic destruction of cells and tissues is solved in different ways by different living things that go into hibernation. In some frogs and newts, for example, the body produces a special antifreeze that protects cells from destruction and death when freezing.
Traces of a similar biological mechanism were found in mammoths. Scientists, in particular, were able to establish that hemoglobin in mammoth blood had special properties that allow non-freezing blood to continue to deliver oxygen to cells even at very low temperatures.
However, it may very well be that mammoths did not build any dens. Moreover, it was very problematic - winters in the critical northern latitudes were then with little snow. But it was quite possible to survive the winter lack of food, severe frosts and snowlessness. On the shores of Antarctica, there are warm-blooded animals that have learned to experience the polar night simultaneously in sleep and in motion. We are talking about emperor penguins.
In the emperor penguin, ecologists have long known the so-called social thermoregulation. When during the polar night the air temperature becomes very low, and piercing winds blow from the ice sheet, 200-300 penguins press tightly against each other and, falling into a somnambulistic state, form an almost regular circle - the so-called "turtle".
This circle slowly, with the speed of an hour hand, continuously rotates around the center. Birds that are outside, tend inward to warm themselves, and push others to the periphery that have already received a portion of heat. This method of thermoregulation is very effective.
Researchers have calculated that in the cold, the penguin alone loses more than 200 grams per day in weight, and while in the "turtle", it consumes only about 100 grams of accumulated fat every day.
MAMMONS OF WRANGEL ISLAND
Many mammoth bones are found on Wrangel Island, located between the East Siberian and Chukchi Seas and 140 kilometers from the nearest land. How did they get there? Presumably, on the ice shell of Arctida. Approximately 10 thousand years ago, when the climate began to warm and the level of the World Ocean rose with the melting of glaciers, the isthmus that connected Wrangel Island with the mainland gradually disappeared.
The Wrangel mammoths were isolated from the mainland. Their relatives and other representatives of the mammoth megafauna were rapidly dying out at that time, but the mammoths of Wrangel Island managed to stretch out at least another 6 millennia.
In the early Holocene, they were probably helped to survive by the inaccessibility and absence of people here. At the same time, there was a decrease in the size of animals, which is so typical for limited populations on remote islands.
Swedish scientists studied the DNA of mammoths from Wrangel Island and found that their genetic diversity remained stable and even gradually increased until the very end, while their disappearance was relatively sudden.
The Swedes named the appearance of a man on the island as a possible reason. But the last mammoths on the island died out 3,700 years ago, and ancient people appeared here 3,300 years ago. In addition, there are no mammoths eaten by humans among the various bones.
The mammoths from Wrangel Island were the smallest members of their species. The height of this dwarf mammoth at the shoulders reached from 1.20 to 1.80 m, while other types of mammoths were twice as large.
Other possible factors in the extinction of mammoths on Wrangel Island are called a catastrophic storm or pandemic. However, until now, microbiologists have not found traces of a virus or bacteria in their bones. Of course, mammoths could also undermine their food base.
Another possible reason for the sudden disappearance of mammoths on the island, according to the writer Nikolai Nepomniachtchi, is the extremely unfavorable conditions of a single winter. The island is located between the Pacific and the Arctic oceans. From the south, masses of warm air occasionally draw here in all seasons of the year. Yuzhak, as the south wind is called here, is fraught with sudden warming of temperature even in the middle of winter.
Heavy rain in winter or late autumn is a disaster for the entire animal population. The resulting thick ice crust prevents herbivores from reaching the food.
On Wrangel Island in 2007, due to the winter rain and the lack of food that followed, almost all the reindeer brought here in the 40s of the last century died. Of the six thousandth herd, no more than 150 heads remained. Something similar could have happened to mammoths.
Victor BUMAGIN