At what depth do diggers live? Naked mole rats will be the key to human immortality, says biologist

Many birds, mammals, reptiles, insects, etc. live on the surface of the earth. However, there are also animals that live underground. This article will tell you about creatures that live underground almost their entire lives. Underground animals - who lives underground photo TOP 10 - look!

Underground animals - who lives underground photo TOP 10

Naked mole rat

Underground animals - who lives underground photo - naked mole rat

This small rodent belongs to the mole rat family. Its distinctive features are cold-bloodedness, lack of sensitivity to pain and various acids. Of all the rodents, the naked mole rat lives the longest - 28 years. Perhaps this baby may outwardly scare someone, but in reality this animal is not aggressive and kind.

Giant mole rat

Underground animals - who lives underground photo - giant mole rat

Of all the representatives of mole rats, the giant mole rat is the largest. This giant reaches 35 centimeters in length and weighs about one kilogram. The upper body is colored light gray or ocher-brown. This underground creature lives only underground, never emerging from its structures. Mole rats love to build multi-tiered systems of entrances and exits. Most often, they dig their feeding passages at a depth of 30-50 centimeters, usually in layers of sand. The entire length of these feeds reaches 500 meters, but there are passages even shorter. Storerooms and nesting chambers of mole rats are located at a depth of up to 3 meters. These creatures have huge teeth that can easily bite through the bayonet of a shovel, so it is better not to pick them up.

Underground animals - who lives underground photo - mole

Even small children know that the mole is an underground animal. Moles belong to mammals, to the order of insectivores. Moles live in Eurasia and North America. Moles come in both very small and large sizes. For example, some of them barely reach 5 centimeters, while others grow up to 20 centimeters. The weight of moles ranges from 9 grams to 170 grams. Moles are perfectly adapted to life underground. The body of these creatures is elongated, round, on which there is smooth and velvety fur. The main feature of the mole, which helps it move in any direction underground, is its fur coat, the fibers of which grow upward.

Tuco-tuco

Underground animals - who lives underground photo - tuco-tuco

Tiny rodents whose weight does not exceed 700 grams. The babies reach 20-25 centimeters in length, and the length of their tail can reach 8 centimeters. The morphological characteristics of these animals fully indicate that they are adapted to life underground. Tuco-tuco leads an exclusively underground lifestyle, they build many intricate passages in which their storerooms, latrines and nesting chambers are stored. Animals use sandy or loose soils to build their home.

Underground animals - who lives underground photo - gopher

The next creature reaches 10-35 centimeters in length, and its tail is 5-15 centimeters. The weight of gophers barely reaches one kilogram. The animals spend most of their lives in their intricate passages, which they make on various soil horizons. The length of the tunnels can reach 100 meters.

spotted snake

Underground animals - who lives underground photo - spotted snake

This species belongs to the cylindrical genus. The snake is quite small in size, but very dense. The color of the snake is black with brown spots arranged in two rows. It lives only underground and feeds on earthworms.

Underground animals - who lives underground photo - simple crucian carp

This fish almost always lives in the bottom mule, but when the reservoir dries up, it burrows underground. Crucian carp can dig from 1 to 10 meters, and can live underground for several years.

Medvedka

Underground animals - who lives underground photo - mole cricket

This insect is one of the largest. The mole cricket can grow up to 5 centimeters in length. The belly of this creature is three times larger than the cephalothorax, soft to the touch, and reaches 1 centimeter in diameter. At the end of the abdomen there are thread-like paired appendages, the length of which is 1 centimeter. Like other creatures on this list, the mole cricket leads an underground lifestyle, but there are times when the insect comes to the surface, usually at night.

Chafer

Underground animals - who lives underground photo - cockchafer

Adults of the eastern type reach a length of 28 millimeters, and of the western type - 32 millimeters. Their body is black and their wings are dark brown. May beetles live underground, but in May they come to the surface and live there for about two months. After two weeks, the mating process occurs, as a result of which the female lays eggs underground at a depth of 20 centimeters. The process of laying eggs can be carried out in several stages at once, as a result of which the female lays about 70 eggs. As soon as the clutch comes to an end, the female immediately dies.

Earthworm

Underground animals - who lives underground photo - earthworm

The worms grow up to 2 meters in length, and their body consists of a huge number of ring-shaped segments. When moving, the worms rely on special bristles, which are located on each ring, with the exception of the front one. The approximate number of bristles on each segment ranges from 8 to several dozen. Earthworms can be found everywhere except Antarctica, as they do not live there. Despite the fact that they lead an underground lifestyle, worms crawl to the surface of the earth after rain, which is why they got their name.

The naked mole rat looks like a raw sausage, lives underground and naturally does not age. Gerontologists around the world believe that this amazing animal will help humanity get rid of old age.

A large-scale study of the most amazing creature living on Earth in terms of aging and longevity began in May 2002 with a message from New York University scientists Rochelle Baffenstein and Jennifer Jarvis: “We present a new world record holder for the longest-lived rodent, the male naked mole rat ( Heterocephalus Glaber). Judging by its weight at capture, this animal was approximately one year old when we collected it near Mtito Andei, Kenya in July-August 1974. He died in April 2002, having shown a life expectancy of more than 28 years."

Although this creature does not shine with beauty (Dr. Crick Faulks from the University of London in an interview with the BBC called the naked mole rat a “saber-tooth sausage”), the close attention of all gerontologists in the world is riveted to it. And this is no coincidence: the difference between the lifespan of a naked mole rat and another similar-sized rodent, a mouse, is the same as that of modern people and the Old Testament prophets, who, according to biblical legends, lived 900 and 1000 years.

If you shoot straight, you live long

Using the example of our grandparents, we know that a person, having crossed the threshold of 50–60 years, usually begins to become decrepit and slowly lose all his functions. Most animals experience similar processes associated with aging: they become decrepit, go bald, lose their eyesight and teeth, suffer from atherosclerosis, and suffer from joint pain. But, as it turned out, among the many species that age according to all the rules, there are unique creatures that are weakly affected by time. And this property of them, which ensures longevity, turned out to be most closely related to living conditions.

The whole point is that the task of any biological species is to leave offspring, to pass on its genes to the next generations. Small animals living in conditions where they are lurked by predators reproduce quickly and live short lives. A typical example is small rodents, which breed in incredible quantities and live a short life of two to three years. The larger and stronger the beast, the fewer enemies it has and the longer its maximum lifespan. This pattern can be traced quite clearly: a mouse lives three years, a rabbit - 12 years, a wolf - 16 years, a tiger - 25, a brown bear - 30, a hippopotamus - 40, an elephant - 70. The record holder for longevity among mammals, crowning this chain, is the bowhead whale. It has no natural enemies at all and can live more than 200 years. Giant turtles, although smaller in size than a whale, also have no enemies (thanks to their impressive shell) and live to be a hundred years or more. All those who have acquired poisonous spines, wings, powerful shells and long claws show a long life expectancy.

Our hero does not have wings or claws, cannot boast of a shell (he does not even have hair) and impressive sizes (his weight is about 30 g with a length of 10 cm). But he was able to find an original solution that provided him with protection from predators and a long life. Like the first Christians persecuted by the Roman authorities, he went underground, where no one could reach him.

The habitat of the naked mole rat is East Africa (Kenya, Ethiopia and Somalia). In arid and hard, concrete-like soil, naked mole rats dig at a depth of one and a half to two meters entire catacombs of underground passages with a total area the size of a large football field, gnawing them with their front teeth. They live in compact and fairly large settlements of up to 300 individuals, almost never come to the surface and do not drink water at all, making do with moisture from their food sources - plant tubers Pyrenacantha malvifolia.

“Scouts” sent to search for food leave chemical marks on their way for their relatives and, having stumbled upon tubers, do not pounce on them immediately, but sound a sound signal meaning: “Guys, food!” The number of sound signals recorded by scientists in naked mole rats, which they use to communicate with each other, is quite large: more than 20 different species.

It is assumed that the formation of a new settlement of naked mole rats begins with the meeting of a female and a male from different settlements, who left their father’s house and decided to start an independent life. In any case, in captivity, these animals prefer to choose partners for procreation not from “relatives”, but from other colonies, thereby avoiding inbreeding.

• The structure of the mole rat community is classified as eusocial (that is, the highest level of social organization) and is similar to families of bees and ants. They have developed cooperation and mutual assistance, as well as social inequality and division into castes. B O The majority of the diggers in the settlement are "workers" and "soldiers" whose only privilege is to work and die defending their comrades. The main and almost only enemies of naked mole rats are snakes. Scientists have encountered evidence of the considerable courage of naked mole rats, invested in them by nature: in the face of danger, the “soldier” mole rat sends a signal to his relatives to wall up the entrance behind him, thus cutting off his path to retreat, and after that he enters into battle with the enemy .


• In addition to working individuals, there are several males - usually two or three for the entire settlement - who are responsible for reproduction. And at the top of this social pyramid is the female queen, who gives birth to the offspring of naked mole rats. These small rodents are extremely fertile, and the female can give birth three to six times a year to two dozen tiny cubs weighing just over a gram. A laboratory female naked mole rat had a record of 900 offspring born in captivity in 11 years.


• Naturally born mole rats are nursed by several females recruited for this task. In October 2015, Japanese scientists published a report on work that made it possible to understand why female mole rats who have not given birth suddenly become “nannies” and show great care for other people’s offspring. It turned out that they eat the feces of the female queen, which contains large amounts of the female hormone estradiol.

Brothers by genes

And yet the main property of this rodent is the almost complete absence of old age in the usual sense of the word. Naked mole rats do not become decrepit, do not suffer from atherosclerosis and diabetes, and retain immunity, as well as muscle and reproductive functions. Almost until the very last days they behave as cheerfully as in their youth. And they die either from skirmishes with the enemy, or the way long-lived people usually die - from cardiac arrest, which has exhausted its resource.

In 2011, a large international team led by Russian geneticist Vadim Gladyshev deciphered the genome of the naked mole rat. The study showed that it separated from its closest “relatives”, mice and rats, 75 million years ago, from the line of rabbits - 86 million years ago, from humans - 102 million years ago. In terms of quantitative characteristics, its genome is similar to the genomes of mice and humans: the DNA of the naked mole rat contains 22,561 coding genes, in humans - 22,389, in mice - 23,317, and 93% of all these genomes are identical.

They also found about 200 new genes that appeared in mole rats after their evolutionary lines split from mice and rats. Changes were also found in the genes of the protein UCP1 and neuropeptide P, which are responsible for the thermoregulation of a cold-blooded animal and make it insensitive to pain. Unlike other mammals, mole rats cannot maintain a constant body temperature (that is, they are cold-blooded) and therefore are forced to move vertically underground, looking for suitable conditions.

Chemistry of youth

But, of course, this was not what primarily interested scientists. Vadim Gladyshev and his colleagues were able to discover a number of identical genes associated with aging in humans, mice and naked mole rats, which worked differently with age in these three species. Probably, one of the most important changes in the naked mole rat were changes in the functioning of the p16 and SMAD3 genes, which slow down the uncontrolled proliferation of cells and are closely associated with many age-related pathologies. It is largely thanks to the work of these genes that naked mole rats are completely immune to dangerous cell degeneration. Another gene, CYP46A1, which is responsible for the health of nerve cells, decreases its activity in the human brain with age, but in the naked mole rat, on the contrary, showed increased expression.

After these pioneering works, other scientists took up the genome of the naked mole rat. In 2013, Russian geneticists from the University of Rochester (New York), Vera Gorbunova and Andrei Seluyanov and colleagues, discovered an increased content of the polysaccharide hyaluronan (hyaluronic acid) in the connective tissue cells of the naked mole rat, fibroblasts. In mole rat cells there was five times more of this substance than in humans or mice. High molecular weight hyaluronic acid accumulated in large quantities in the naked mole rat's tissues because the enzymes responsible for breaking it down were inhibited. And the enzyme that synthesizes this acid, hyaluronan synthase-2 (HAS2), on the contrary, showed increased activity in mole rats.

It also turned out that human and naked mole rat hyaluronans, due to their different molecular weights (in mole rats it is five times larger), have opposite effects on the body. Small human (and mouse) hyaluronans stimulate inflammation and cell division, while large naked mole rat hyaluronans, on the contrary, suppress inflammation and cell division, preventing the development of cancer.

The discovery of hyaluronic acid in mole rat tissue helped explain the extreme resistance of these rodents to the effects of reactive oxygen species (ROS). ROS are produced in most organisms as a by-product of oxygen consumption and at high concentrations (which often occurs in old age) can damage cell membranes and DNA, killing the cell.

There are a number of other features of naked mole rats that are still awaiting explanation. This is the unusual structure of the RNA ribosome (the cellular organelle in which the formation of newly synthesized proteins occurs), and a mutation of the insulin receptor, as a result of which the mole rat absorbs glucose bypassing insulin, and much more. Thus, through the joint efforts of many researchers, a complete picture is gradually emerging of the amazing phenomenon of health and longevity of this mysterious underground rodent, which nature and evolution, on some whim, chose as their favorite, endowing it with a whole set of unique qualities. It can be assumed that new discoveries will soon appear that can greatly help humanity in the fight against aging and age-related diseases.

Row - Rodents
Family - Zemlekopov
Genus/Species - Heterocephalus glaber
Basic data:
Body length: 8-9 cm.
Weight: about 40 g
Pregnancy: 70 days.
Number of cubs: 3-11.
Lifestyle.
Habits: lives in underground galleries; never comes to light.
Food: tubers and roots.
Lifespan: in captivity for about 5 years.
Related species. The mole rat family includes five genera and sixteen species. They are all found in sub-Saharan Africa. The naked mole rat's closest relative is the Cape mole rat.
The naked mole rat lives in the savannas and semi-deserts of Somalia. It feeds on the roots and tubers of plants, both wild and cultivated.
Sometimes the naked mole rat eats only part of the found tuber and covers the gnawed hole with earth so that the potato can grow further; This is how the animal provides itself with food for the future. The naked mole rat gets all the water it needs from plants, so it can do without a watering hole. The naked mole rat is missing an upper lip. The long incisors, the roots of which are located in front of or behind the molars, form part of the nostrils on top.
To prevent sand from entering the constantly open nostrils, they are protected on top by a fold of skin, which is called the “false lip.” The metabolism of this animal is very slow, which is caused by the surprisingly low temperature of its body, which is only 30-35 C. Therefore, the animal gets by with less food than other mammals of the same size.

Lifestyle. The naked mole rat lives underground in the hot, arid regions of the Somali Peninsula. The animals form colonies, which usually number from 20 to 30 individuals, inhabiting a complex system of long underground tunnels over an area of ​​3-4 km.
Naked mole rats dig underground corridors at a depth of about 20 cm from the surface. These passages are quite narrow and animals can only move through them one after the other. In the underground town there are also wider tunnels, located at a depth of 50 cm, in which two animals can separate. When two individuals meet in such a corridor, the smaller animal usually shrinks so that the other digger can squeeze in next to it, or they both press against the walls and so separate. At the level of the wide corridors there are nesting chambers. The latrines are located at approximately the same level or a little deeper. Some of the deeper tunnels end in dead ends. In a colony of naked mole rats, only the queen has the ability to reproduce.
The queen has from one to three partners. Other animals in the colony are infertile. Animals belonging to different castes perform specific functions. The task of working diggers is to collect and deliver food, nesting material, dig galleries and protect the colony from enemy attacks.

Reproduction of the naked mole rat. The queen naked mole rat mates every 80 days, this occurs 8-11 days after the last birth. She decides when mating will occur. To do this, the queen, emitting a high-pitched squeak, calls her partners. The queen mates with every mature male of her group. In the community of mole rats, there are no fights between males.
Newborn cubs are cared for by the queen, her mates and, to a lesser extent, other members of the colony. Young animals often help their mother raise younger brothers and sisters.
The newborn is bright pink. It weighs only two grams, but within a few hours after birth the cub gets to its feet and can dig in the ground. Babies begin to eat solid food at the age of three to four weeks. Until the age of two, young people willingly play with each other.
When the queen becomes unable to reproduce, a fight for the “title” occurs between the females. Scientists do not know how the queen manages to suppress the sexual desire of other individuals. Perhaps she secretes a special hormone along with her urine that blocks the ability of other females to mate.

Characteristics.
Ears: formed simply by ear openings, there are no auricles.
Skin: completely bare except for a few isolated hairs.
Eyes: tiny. The naked mole rat's vision is very poorly developed. He's almost blind.
Teeth: two pairs of long incisors that protrude outward, used to gnaw roots and tubers, dig tunnels and protect themselves from snakes.
Claws: short but sharp. With their help, the digger can easily move along underground corridors.
Places of residence. The naked mole rat lives in the savannas and semi-deserts of the Somali Peninsula, in Southern Ethiopia, Eastern Kenya and most of Somalia.
Preservation. The naked mole rat is quite numerous in areas of its range. Thanks to its underground lifestyle, it is protected from the influence of the outside world. The naked mole rat's most dangerous enemies are snakes.

Interesting video about the naked mole rat

Science and new technologies have always been an expensive pleasure. The world's leading powers spend billions every year on research, instead of spending money on fighting poverty and unemployment or on health care and education.

It is sometimes difficult for ordinary citizens to agree with the expediency of such expenses, because outwardly many studies and experiments seem useless and their results seem to have no application in real life. Is it really? Let's try to figure it out with an example... naked mole rats.

UNDERGROUND LIVES

Naked mole rats (lat. Heterocephalus glaber) live underground, in the savannas and semi-deserts of Africa, and millions of dollars have been spent on studying these creatures in recent years.

Millions of dollars for practically hairless and blind rodents, which 99% of people living on our planet have never heard of! Are such expenses justified? From the point of view of the inhabitants of Somalia, Ethiopia and Kenya, in whose territory this living creature lives, definitely not, but for scientists these underground creatures are of extreme interest.

First, it is the only known vertebrate that is insensitive to types of pain such as thermal burns and chemical acid burns. A naked mole rat can be gently rubbed with acid or a cigarette butt gently put out on his body - and this will not cause any objections or panic on his part.

The reduced sensitivity of these rodents is associated with the absence of a neurotransmitter in the skin cells, also known as “substance P,” which is responsible for transmitting pain impulses to the central nervous system.

Secondly, these mammals lead a eusocial lifestyle, that is, a standard community of 80-100 individuals lives as one large organism with a collective mind. Rodents in such colonies are divided into castes, among which there are workers who build tunnels, service personnel involved in collecting food and caring for offspring, and soldiers who protect the population from, perhaps, the only enemies - snakes.

At the head of such a community is the queen - the only female capable of reproducing. There are two or three favorites next to her. This is widespread among insects - ants, termites and bees, but in the world of mammals, except for the mole rat, only the Damara minnow, a rodent that, by the way, also belongs to the mole rat family, can boast of such a social system.

The third feature is that naked mole rats are the only mammals that do not have a constant body temperature and are able to adapt to the temperature of the environment. They do not waste physical resources and, if necessary, warm themselves either with each other or with work, digging many kilometers of underground passages with their powerful teeth.

But their main feature is that diggers practically do not age and are not susceptible to cancer! And it was these, let’s say, superpowers that interested smart people in scientific circles. It's no joke, in the hands of humanity there may be the key, if not to immortality, then at least to multiple extension of life. Not taking advantage of such a gift is simply a sin...

KEY TO IMMORTALITY

Rodents familiar to us, for example mice, rarely live more than three years, while naked mole rats often pass the thirty-year mark. For a mammal of this size (10 cm in length and 30-80 grams of weight), this is the same as for a person to live for five hundred years. Having mentioned that the digger does not age, it should be noted that he does not age at all.

No matter how fantastic it sounds, over the years, no age-related changes occur in his body. The internal organs of an elderly animal remain the same as those of its young counterparts, and death, apparently, comes only because of a gene inherent in evolution, designed to help renew generations.

The main experts in the study of naked mole rats are our compatriots Vera Gorbunova and Andrei Siluyanov, who now work at the University of Rochester (USA). They came close to unraveling the secret of the African rodent, identifying an unusual type of hyaluronic acid in its body.

Hyaluronic acid was discovered in 1934 by researchers Carl Meyer and John Palmer, scientists at Columbia University in New York. This curious substance, although not an elixir of youth, does help slow down aging, which has made it the object of close attention.

The body of an average person weighing 70 kilograms contains only 15 grams of hyapuronan, a third of which is renewed daily, that is, broken down and synthesized again. Over the years, the production of hyaluronic acid sharply decreases, which is why the skin loses its elasticity, wrinkles appear and joint diseases make themselves felt.

Nowadays, hyaluronic acid is one of the most popular drugs in modern cosmetology, and countless show business stars and wealthy people who seek to prolong their youth resort to rejuvenating injections of this substance. True, the effect of “rejuvenation” injections on humans is not as great as we would like.

The reason for this, according to scientists, is that the human body produces low-molecular-weight hyaluronic acid, while naked mole rats are able to synthesize higher-grade high-molecular-weight hyapuronan, which, among other things, provides protection against cancer.

On April 6-10, 2014, the III International Conference “Genetics of Aging and Longevity” was held in Sochi, where Professor Siluyanov shared information about his current work: “We are now making a mouse that will have the naked mole rat gene, allowing the production of hyaluronic acid, and I hope that this mouse will be protected from cancer and live longer. Probably, if this experiment turns out to be successful, we will try to transfer this practice to the clinic.”

ALL HOPE IS FOR THE MOLE CHILD

Immortality, or at least life extension, has been a fixed idea throughout human history, and naked mole rats are officially recognized as one of the twenty-five ways to achieve this goal. However, if successful, the availability of the latest drugs for ordinary people is questionable.

Given the overpopulation of the planet, it is unprofitable to produce centenarians, just as it is unprofitable to immediately treat the 12 million people who, according to WHO - the World Health Organization - get cancer every year around the world.

The reality of the modern world is that if a breakthrough cure for cancer is created, pharmaceutical companies will try to make the most of it, and the price for the opportunity to live longer will be prohibitively high. However, this will happen only with a monopoly on a possible miracle drug, when there is no alternative to Western developments.

Unfortunately, in Russia, the study of the long-lived African rodent has not even begun, although the Novosibirsk Institute of Systematics and Animal Ecology has been working on anti-aging for several years. Instead of the naked mole rat, our scientists are studying another underground inhabitant - the mole vole.

The mole vole (lat. Ellobius talpinus) is a close relative of the hamster and the field mouse. And just like its naked African counterpart, it digs tunnels and feeds on plant roots. This animal has plenty of features and mysteries that are interesting to science, but the main one is, of course, aging.

Or rather, its absence, because after numerous experiments and observations, scientists have not identified any age-related changes in mole voles. Regardless of age, activity, mobility, energy exchange and other important indicators in mole voles remain at the same level, which contradicts observations of mammals.

“We are not in a hurry to talk about a scientific sensation yet,” explains Evgeniy Novikov, leading researcher at the Laboratory of Physical Adaptations of Vertebrate Animals, “since the evidence that the mole vole does not age is still unofficial. First, our research must undergo careful statistical processing, and only after that we can make such statements.

Now mole voles raised in Novosibirsk are being monitored in the laboratory of Moscow State University, and scientists have yet to establish how long the rodents can live in normal human conditions, and not in the harsh Siberian climate. It’s a pity that all the necessary research will take a lot of time, but even the theoretical possibility of defeating old age warms the soul, and the millions allocated to science will sooner or later pay off.

Andrey RUKHLOV