Today on Earth there are several dozen species of rats, but most of them live in the tropics, are relatively few in number and rarely meet with humans. Another thing is two synanthropic species (living in the neighborhood of a person or in his home) - the black rat (Rattus rattus) and the gray rat (Rattus norvegicus), which have settled throughout the planet, except for the Arctic and Antarctic.
Another synanthropic species lives on the territory of our country - the Turkestan rat, but its range is small and limited to Central Asia.
Scientists believe that there are about twice as many rats as people (we are talking about a gray and black rat), and in metropolitan areas, such as New York, there are several rats per person. According to experts, over 60 million of these rodents live in the UK, and in Moscow the rat population is estimated at about 40 million.
So, meet - Rattus norvegicus, a gray rat (it is a barn, red and pasyuk). It is a rather large rodent with a wide blunt muzzle and rounded ears. The body length without tail is from 17 to 40 centimeters, weight is from 140 to 463 grams, but it can reach 500-600 grams (and some specimens sometimes weigh more than a kilogram). The color is dark gray, but with age it acquires a reddish tint. The tail is always shorter than the body.
The homeland of the gray rat is considered to be East Asia, where it lived in the Ice Age, and with the beginning of warming (12-13 thousand years ago) it gradually moved to the west. The settlement went very slowly - for 13 thousand years it settled in Altai, Transbaikalia and South Primorye, and by the 1st century AD it penetrated the Indian subcontinent.
In the 7th-15th centuries of the new era, the gray rat populated the port cities of the Persian Gulf, the Red Sea and East Africa, to which, no doubt, Arab sailors had a hand. And only by the XV-XVI centuries, when the Europeans opened the eastern route to India and an active sea trade developed, the gray rats also got to Europe.
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The gray rat is sometimes called the Norwegian. This is the fault of the Scottish naturalist John Berkenhout, who described in 1769 a new species of rodent according to all the rules of biological taxonomy. He believed that the rats sailed to England with Norwegian ships, although in fact the transit point on the road to the British Isles was most likely Denmark. And in general, the first half of the 18th century, on which the Scotsman stubbornly insisted, was too late a date for the rat's expansion. There are good reasons to believe that Europeans first met the gray rat in the 15th or 16th century.
By the beginning of the 19th century, the pasuk had spread everywhere, settling in America, Australia and New Zealand. Today it is the dominant species, which has pretty much surpassed its black counterpart (Rattus rattus).
The black rat is much more graceful and smaller than the gray - from 15 to 22 centimeters in height and no more than 300 grams in weight. She has a long tail and darker coloration. The black rat is a wonderful tightrope walker and steeplejack: it easily climbs a steep wall, moves along the ceiling, clinging to wires, and can even walk along a stretched wire.
Unlike the Pasyuk, who likes to settle in basements, underground utilities, in landfills and in metro tunnels, the black rat prefers dry attics. And in nature, she even leads a semi-woody lifestyle, arranging nests among the branches, while the gray rat digs holes along the banks of water bodies.
Due to the mismatch of ecological niches, gray and black rats do not compete too fiercely: between these species, as biologists say, "vertical coexistence" has been established.
It is believed that Europeans were already well acquainted with the black rat in late Antiquity (the first centuries of the Christian era), but other scientists are convinced that it penetrated Europe in the early Middle Ages (around the 10th century or even later - in the 13th century).
It's time to recall the plague pandemic of the XIV century, which killed a quarter of the population of Europe at that time, because epidemiologists associate it with the black rat.
The "Black Death", as the plague was called at the time, was apparently brought to Europe through Genoa, Venice and Naples, the largest port cities of the time. Initially breaking out in Asia, the epidemic then devastated Thrace, Macedonia, Syria, Italy, Greece, France, England, Spain and Germany, catching in passing Poland and Russia.
In Venice, about 100,000 inhabitants died (70% of its then population), and London turned into a gigantic cemetery: the plague took nine-tenths of its inhabitants to the grave. Norway is also almost depopulated - four fifths of the total population died there. According to the estimates of the German medical historian G. Geser, the "black death" pandemic destroyed about 50 million people on the globe.
According to some scientists, the famous epidemic, which wiped out from a quarter to a third of the entire population of medieval Europe, was provoked to a certain extent by the Europeans themselves. According to this original hypothesis, one of the reasons for the rapid and sudden spread of the formidable infection beyond the natural focus was the aggressive foreign policy of the royal courts of Western Europe, approved and supported by the Vatican.
The fact is that by the beginning of the XIV century, the crusades had just ended, when the valiant knights went to Palestine to fight the Holy Sepulcher. From the burning sands of the fertile crescent, as these lands are sometimes called, they brought not only countless treasures taken from the Arab rulers, but also a black rat. More precisely, the rat set off on a journey-road of its own free will and partly sailed on the ships of the Venetians, and partly came on foot along with the crusader army by land.
Europe at that time was inhabited by another species of synanthropic rodents, of which today only memories remain, because the fierce black beast, having settled in a foreign land, first began to exterminate these aborigines. And together with the overseas guest came "the terrible plague queen."
The outrageous medieval unsanitary conditions, when human housing (both the palaces of the nobility and the huts of the poor) was literally swarming with parasites, including fleas, led to the fact that the epidemic began to rapidly gain momentum. An additional argument in favor of this version is the point of view of zoologists, according to which the black rat settled in Europe just in the XIII century.
But even if rats were not carriers of dangerous infections (in addition to plague, they spread rabies, tularemia, toxoplasmosis, typhoid fever, etc.), they would still cause a lot of trouble for mankind, which, by the way, is what actually happens.
And since the pasuk is the dominant species in the family of rats, we will mainly talk about it.
The gray rat is an intelligent, resourceful, extremely cautious and completely fearless creature. She is eminently endowed with an exploratory instinct, extremely curious and always ready to step into the unknown, regardless of risk. A rat rarely attacks a person, but if its escape routes are cut off, it will not hesitate to go on the attack. No wonder they say: "Fights like a rat cornered."
American writer Ernest Seton-Thompson told how, as a child, he and a friend managed to catch a large gray rat. The boys took her to a dentist they knew who kept rattlesnakes. Before giving the rat to the snakes, the prudent doctor tore out the incisors.
Once in the terrarium, the crippled rat dashed from corner to corner for a long time, fleeing four hungry snakes, but as soon as it missed and missed the fatal blow, it immediately went on the attack. Paying no further attention to the bites, she grabbed one of the snakes by the neck with her toothless jaws and shook it violently until she broke her spine.
Leaving the snake to die, the rat with a death grip grabbed the throat of her companion, although by this time the rat had already lost its hind legs. In short, the fearless rat strangled all four snakes and died on its own.
This story testifies not only to the courage of the rat, but also to its extraordinary intelligence: having missed the snake bite, the animal realized that it had nothing more to lose and went ahead.
Intelligence, fearlessness and caution, plus a high level of aggressiveness and rare fertility provided the gray rat with evolutionary success. Pasyuk breeds all year round, and there can be up to 22 pups in a litter (on average there are about 10), and there are eight or even more such litters per year. The black rat is much more peaceful and brings no more than 6-7 cubs at a time.
The gray rat is an excellent athlete: it easily winds several tens of kilometers in a day, and in a jerk is capable of reaching speeds of up to 10 km / h, swims and dives remarkably (in natural conditions it hunts for water game) and demonstrates excellent jumping ability - up to one and a half meters in length and one meter high.
They say that in a critical situation, the Pasyuk can fly up to almost two meters. The gray rat can easily swim several kilometers, and the reliably recorded result of its stay in the water is 72 hours.
Rats are omnivores and eat with pleasure everything that is good for food and people. In rat stomachs, one fifth of all grain crops disappear annually, and in Asia, rats eat about 50 million tons of rice every year, which would be more than enough to feed a quarter of a billion people.
Aggressive and eternally hungry goose are also carnivorous: bursting into a flock of geese, they gnaw the webbing on the paws of birds, and they catch ducklings right in the water. In domestic cattle - sheep and pigs - rats eat meat from the sides, and from the calf they can generally leave only bones. Rats attack people relatively rarely, but frail old people and small children can easily become their victims.
Pasyuks are extremely hardy and unpretentious - they are not afraid of either high or low temperatures. Settling in industrial refrigerators in the depths of frozen meat carcasses, they survive at a temperature of -17 ° C and not only survive, but also give birth, and nests, in the absence of other available material, are built from tendons that are gnawed from the same carcasses.
The main rat weapon is razor-sharp incisors that grow throughout life. Therefore, they gnaw on everything: leather, wood, bones, insulation of electrical and telegraph cables and even soft metals - tin, lead, copper and aluminum. Concrete is not a hindrance to them either. The pressure developed during the bite is 500 kg / cm2, so only hardened steel can withstand the rat.
But the most striking thing is an ineradicable rat curiosity. Being by nature secretive and cautious animals, rats prefer stability to everything in the world and rarely deviate from the well-known paths. But in any rat community, there are always desperate explorers who leave their familiar surroundings and hit the road, despite the dangers. They are in a state of extreme stress: their eyes are burning, their fur stands on end, but they still rush forward and only forward. The adrenaline rush acts like a drug.
There are legends about the rats' quick wits. For example, they know how to extract ghee from a sealed bottle. The rat first knocks it down on the floor, pulls out the cork with its teeth, runs its tail into a narrow neck, and then licks it.
The operation is repeated several times, and the oil level melts before our eyes. But the rat is a born collectivist, so the next day it appears at the head of a whole brood of eight young rat pups. The young people watch how their mother handles a cunning vessel, and soon the whole family is licking their oiled tails.
Rats are equally adept at stealing eggs. The animal lies on its back and presses the egg to its stomach, grasping it tightly with all four paws, and the other rat taps the first by the tail. Method number two: the rat, seizing the egg with its teeth and front paws, jumps on its hind legs like a kangaroo.
Rats are perfect for solving the most difficult labyrinths. In any case, scientists have not been able to build such a labyrinth that at least one of the experimental rodents did not master. And when they were taught to climb from shelf to shelf on ladders, the rats got down to business creatively: having climbed the second shelf, they dragged the ladder up and leaned it against the third shelf, where the treat lay.
And rats are great at recognizing patterns, even when they are part of a completely different pattern. Changing its size will also not confuse the rat. So scientists had every reason to say that gray rats in their intellectual talents are not inferior to the smartest dogs.
Rats are very conservative in their habits: if you change things in a familiar environment, the animal will instantly be on the alert and think a hundred times before approaching a dangerous, from his point of view, object. If an unwary rat accidentally falls into a trap, the relatives will never leave it in trouble, they will try to rescue it.
However, rats rarely fall into traps: they either simply bypass them, or discharge the mechanism by extracting the bait. An experienced rat who has seen a lot in his life will always figure out the most cunning trap.
Poisoning rats with poison is a futile occupation. There is always a potential suicide bomber in a rat flock who is ready to try poison bait on the tooth, and if something happens to him, no one will touch the poisoned food anymore.
I must say that rats in general perfectly recognize poisons and adapt remarkably to them. None of those poisons that were used in the 50-60s of the last century have no effect on modern rats. And when biologists began to use complex poisons with a long incubation period (so that an intelligent rodent could not link cause and effect), rats quickly became immune to them.
But the most amazing property of rats is the preservation of the acquired experience and its transfer from generation to generation. A rat that has dealt with a dangerous bait has long been dead, but its descendants cherish valuable experience.
Both pasiuk and black rats live in large communities of tens and even hundreds of individuals (up to 300). At the same time, like all herd animals, there is an intricate system of complex hierarchical relationships within the flock.
In rat packs, animals identify each other by smell (the community is too large for its members to know everyone by sight). Love and harmony reign inside the colony. Konrad Lorenz described the rat family as follows:
“Peacefulness, even tenderness, which distinguishes the attitude of mammalian mothers to their children, in rats is characteristic not only of fathers, but also of grandfathers, as well as all kinds of uncles, aunts, great-uncles, etc., etc. - I don’t know, before what degree of kinship.
Mothers bring all their broods to the same nest, and one can hardly assume that each of them cares only for their own children. Even in packs of wolves, whose members are so courteous to each other, the beasts of the highest rank eat the common prey first. There is no hierarchy in a rat flock."
The pack attacks large prey together, and the stronger members contribute more to the victory. And then miracles begin: the young get a large share, and the adults are content to pick up scraps, and they do it quite voluntarily.
Events develop in a similar way during mating: more frisky animals, barely half grown, are ahead of the patriarchs. Biologist F. Steiniger, who studied this curious phenomenon, wrote about it this way: "The young have all rights, and even the strongest of the old does not challenge them."
However, the idyll described above exists only between “friends”. If someone else's rat gets on the territory of the colony, an instant and ruthless reprisal awaits it. As soon as it is sensed, the flock raised by alarm will instantly come to a state of excitement (hair on end, eyes bulge out of their sockets), and the hunt will begin.
The same will happen if you take a rat from the family, keep it for some time in another place so that it loses its "passport" smell, and then return it back. The returned rat will behave friendly, because it has not yet forgotten the smell of its pack, but nevertheless it will be torn to pieces by relatives.