Animals that walk on flippers or pinnipeds. Geographical laws and some environmental factors Why do animals to the south have larger ears

Ecology

Human hands are one of the most important parts of the body. With the help of hands, we do almost everything, even communicate. However, man is not the only creature on the planet with dexterous hands and fingers. The limbs of animals that are commonly called paws, may surprise you. We invite you to learn about the most unusual paws in the animal kingdom.

amazing animals

Threatening Ai-Ai

Ay-ay- an amazing creature that lives in Madagascar, which knows how to "show the middle finger" like no one else in the world. Ay-ay or little arm- a small primate that can be called the strangest of all primates. He has ugly bony paws with long fingers and claws, which reminds of the heroes of fairy tales about vampires and werewolves.

Moreover, the middle finger of the handle is slightly larger than the rest and protrudes noticeably. With his help, the beast knocking on trees in search of voids in the bark where the delicious insects that it feeds on can hide. If the aye-aye finds a treat, he bites through the wood and with his sinister long finger catches the prey.

Arms, despite their menacing appearance, completely harmless for everyone except insects, however, the inhabitants of Madagascar are very unfriendly to these animals, considering meeting with them a bad sign. If an aye-aye is seen near the village, he will be killed immediately, as it is believed that otherwise misfortune will fall on the village.

Flying Frog Helen

In 2009, while traveling through the forest near the Vietnamese city of Ho Chi Minh City, biologists stumbled upon an amazing frog. This frog is long about 9 centimeters, as it turned out, belonged to a new species of flying frogs unknown to science, which are known for their ability to jump from one tree to another and float in the air with the help of special webbed paws.

Biologist Judy Rowley who discovered this frog in Vietnam gave it its name flying frog Helen in honor of his mother Helen Rowley.

The most amazing animals

polydactyl mole

Moles- very cute animals, except, perhaps, starfish mole, which lives in the US and Canada. Moles have amazing limbs, which they simply need in order to travel underground.

Large flat front paws work like shovels, and long claws on the fingers allow dig underground burrows and tunnels in which moles find shelter and food.

In 2011 researchers University of Zurich suggested why the mole's paws dig the ground so well: moles have one extra finger- sickle-shaped spare thumb.

This thumb has no motor joint, mole relies on it while digging, which gives his spade legs extra strength. Studies have shown that the bone of this finger develops from the bones of the wrist at the embryonic stage somewhat later than the bones of the other fingers. Moles really have not 5, but 6 fingers on paws!

sticky gecko

geckos boast amazing legs that allow them to cling to almost for any surface. The lines on the soles of their feet are covered with hairs called bristles, which are also covered with bristles.

The latter structures are so shallow that they allow geckos to stick to the surface they move on. They allow you to enhance van der Waals force, the weak electrical force that holds many things together, including most organic matter.

In this post there will be scary, nasty, cute, kind, beautiful, incomprehensible animals.
Plus a short comment about each. They all really exist.
Watch and be amazed

SCHELEZUB- a mammal from the order of insectivores, divided into two main species: the Cuban flint tooth and the Haitian. Relatively large, relative to other types of insectivores, the beast: its length is 32 centimeters, and the tail, on average, 25 cm, the weight of the animal is about 1 kilogram, the physique is dense.


MANED WOLF. Lives in South America. The long legs of the wolf are the result of evolution in matters of adaptation to the habitat, they help the animal overcome obstacles in the form of tall grass growing on the plains.


AFRICAN CIVETA- the only representative of the same genus. These animals live in Africa in open spaces with high grass from Senegal to Somalia, southern Namibia and eastern South Africa. The dimensions of the animal can visually increase quite strongly when the civet raises its hair when excited. And her fur is thick and long, especially on the back closer to the tail. The paws, muzzle and end of the tail are absolutely black, most of the body is spotty-striped.


MUSKRAT. The animal is quite famous, thanks to its sonorous name. It's just a good photo.


PROEKHIDNA. This miracle of nature usually weighs up to 10 kg, although larger specimens have also been noted. By the way, the length of the body of the prochidna reaches 77 cm, and this is not counting their cute five to seven centimeter tail. Any description of this animal is based on comparison with the echidna: the paws of the echidna are higher, the claws are more powerful. Another feature of the appearance of the prochidna is the spurs on the hind legs of males and the five-fingered hind limbs and the three-fingered forelimbs.


CAPIBARA. Semi-aquatic mammal, the largest of modern rodents. It is the only representative of the capybara family (Hydrochoeridae). There is a dwarf variety of Hydrochoerus isthmius, sometimes considered as a separate species (capybara).


SEA CUCUMBER. Holothuria. Sea-pods, sea cucumbers (Holothuroidea), a class of invertebrates of the echinoderm type. Species eaten are collectively called "trepang".


PANGOLIN. This post just couldn't do without it.


HELL VAMPIRE. Mollusk. Despite its obvious similarity with the octopus and squid, scientists have identified this mollusk in a separate order Vampyromorphida (Latin), because as soon as it has retractable sensitive bee-shaped filaments.


AARDVARK. In Africa, these mammals are called aardvark, which means "earth pig" in Russian. In fact, the aardvark in appearance very much resembles a pig, only with an elongated muzzle. The ears of this amazing animal are very similar in structure to those of a hare. There is also a muscular tail, which is very similar to the tail of such an animal as a kangaroo.

JAPANESE GIANT SALAMANDRA. To date, this is the largest amphibian that can reach 160 cm in length, weigh up to 180 kg and can live up to 150 years, although the officially registered maximum age of a giant salamander is 55 years.


BEARDED PIG. In different sources, the bearded pig species is divided into two or three subspecies. These are the curly-haired bearded pig (Sus barbatus oi), which lives on the Malay Peninsula and the island of Sumatra, the Bornean bearded pig (Sus barbatus barbatus) and the Palawan bearded pig, which, judging by the name, live on the islands of Borneo and Palawan, as well as in Java , Kalimantan and small islands of the Indonesian archipelago in Southeast Asia.




SUMATRAN RHINO. They belong to the equine-hoofed animals of the rhinoceros family. This species of rhinoceros is the smallest of the entire family. The body length of an adult Sumatran rhinoceros can reach 200 - 280 cm, and the height at the withers can vary from 100 to 150 cm. Such rhinos can weigh up to 1000 kg.


SULAWESI BEAR CUSCOUS. An arboreal marsupial living in the upper tier of lowland tropical forests. The coat of the bear couscous consists of a soft undercoat and coarse guard hairs. Color ranges from gray to brown, with a lighter belly and limbs, and varies by geographic subspecies and age of the animal. The prehensile, hairless tail is about half the length of the animal and acts as a fifth limb, which makes it easier to move through the dense rainforest. Bear couscous is the most primitive of all couscous, retaining primitive tooth growth and skull features.


GALAGO. Its large fluffy tail is clearly comparable to that of a squirrel. And the charming muzzle and graceful movements, flexibility and insinuation, clearly reflect his feline trait. The amazing jumping ability, mobility, strength and incredible agility of this animal clearly show its nature as a funny cat and elusive squirrel. Of course, it would be where to use their talents, because a cramped cage is very poorly suited for this. But, if you give this little animal a little freedom and sometimes allow him to walk around the apartment, then all his quirks and talents will come true. Many even compare it to a kangaroo.


WOMBAT. Without a photograph of a wombat, it is generally impossible to talk about strange and rare animals.


AMAZONIAN DOLPHIN. It is the largest river dolphin. Inia geoffrensis, as scientists call it, reaches 2.5 meters in length and weighs 2 centners. Light gray juveniles lighten with age. The body of the Amazonian dolphin is full, with a thin tail and a narrow muzzle. A round forehead, a slightly curved beak and small eyes are the features of this species of dolphins. There is an Amazonian dolphin in the rivers and lakes of Latin America.


FISH-MOON or MOLA-MOLA. This fish can be over three meters long and weigh about one and a half tons. The largest specimen of the moonfish was caught in New Hampshire, USA. Its length was five and a half meters, data on weight are not available. In shape, the body of the fish resembles a disk, it was this feature that gave rise to the Latin name. The moonfish has thicker skin. It is elastic, and its surface is covered with small bony protrusions. Fish larvae of this species and juveniles swim in the usual way. Adult large fish swim on their side, quietly moving their fins. They seem to lie on the surface of the water, where they are very easy to notice and catch. However, many experts believe that only sick fish swim in this way. As an argument, they cite the fact that the stomach of fish caught on the surface is usually empty.


TASMANIAN DEVIL. Being the largest of modern predatory marsupials, this animal is black in color with white spots on the chest and rump, with a huge mouth and sharp teeth, has a dense physique and severe disposition, for which, in fact, it was called the devil. Emitting ominous cries at night, the massive and clumsy Tasmanian devil outwardly resembles a small bear: the front legs are slightly longer than the hind legs, the head is large, and the muzzle is blunted.


LORI. A characteristic feature of the loris is the large size of the eyes, which can be bordered by dark circles, there is a white dividing strip between the eyes. The muzzle of a lory can be compared to a clown mask. This most likely explains the name of the animal: Loeris means "clown" in translation.


GAVIAL. Of course, one of the representatives of the detachment of crocodiles. With age, the muzzle of the gharial becomes even narrower and longer. Due to the fact that the gharial feeds on fish, its teeth are long and sharp, located with a slight inclination for the convenience of eating.


OKAPI. FOREST GIRAFFE. Traveling in Central Africa, journalist and African explorer Henry Morton Stanley (1841-1904) encountered local natives more than once. Having once met an expedition equipped with horses, the natives of the Congo told the famous traveler that they had wild animals in the jungle, very similar to his horses. The Englishman, who had seen a lot, was somewhat puzzled by this fact. After some negotiations in 1900, the British were finally able to purchase parts of the skin of a mysterious beast from the local population and send them to the Royal Zoological Society in London, where they gave the unknown animal the name "Johnston's Horse" (Equus johnstoni), that is, they identified it as a member of the horse family. . But what was their surprise when, a year later, they managed to get a whole skin and two skulls of an unknown animal, and find that It looks more like a pygmy giraffe from the Ice Age. Only in 1909 was it possible to catch a live specimen of Okapi.

VALABY. WOOD KANGAROO. To the genus Tree kangaroos - wallabies (Dendrolagus) include 6 species. Of these, D. Inustus or bear wallaby, D. Matschiei or Matchish wallaby, which has a subspecies D. Goodfellowi (Goodfellow wallaby), D. Dorianus - Doria wallaby, live in New Guinea. In Australian Queensland, there are D. Lumholtzi - Lumholtz's wallaby (bungari), D. Bennettianus - Bennett's wallaby, or tharibina. Their original habitat was New Guinea, but now wallabies are also found in Australia. Tree kangaroos live in the tropical forests of mountainous regions, at an altitude of 450 to 3000m. above sea level. The body size of the animal is 52-81 cm, the tail is from 42 to 93 cm long. Wallabies weigh, depending on the species, from 7.7 to 10 kg males and from 6.7 to 8.9 kg. females.


WOLVERINE. Moves quickly and dexterously. The animal has an elongated muzzle, a large head, with rounded ears. The jaws are powerful, the teeth are sharp. Wolverine is a “big-legged” beast, the feet are disproportionate to the body, but their size allows them to move freely through the deep snow cover. Each paw has huge and curved claws. Wolverine climbs trees perfectly, has sharp eyesight. The voice is like a fox.


FOSS. On the island of Madagascar, such animals have been preserved that are not found not only in Africa itself, but throughout the rest of the world. One of the rarest animals is Fossa - the only representative of the genus Cryptoprocta and the largest predatory mammal that lives on the island of Madagascar. The appearance of the fossa is a bit unusual: it is a cross between a civet and a small cougar. Sometimes the fossa is also called the Madagascar lion, since the ancestors of this animal were much larger and reached the size of a lion. Fossa has a squat, massive and slightly elongated body, the length of which can reach up to 80 cm (on average it is 65-70 cm). The legs of the fossa are long, but thick enough, with the hind legs higher than the front ones. The tail is often equal to the length of the body and reaches 65 cm.


MANUL approves of this post and is only here because it should be. Everyone knows him.


FENEC. STEPPE FOX. He agrees with the manula and is present here in so far as. After all, everyone saw him.


THE NAKED DIGGER puts the manula and the fennec fox in karma and invites them to organize a club of the most feared animals in Runet.


PALM THIEF. A representative of the decapod crustaceans. Which habitat is the western part of the Pacific Ocean and the tropical islands of the Indian Ocean. This animal from the family of land crayfish is quite large for its species. The body of an adult individual reaches a size of up to 32 cm and a weight of up to 3-4 kg. For a long time, it was erroneously believed that with its claws, it can even crack coconuts, which it then eats. To date, scientists have proven that cancer can only eat already split coconuts. They, being its main source of nutrition, gave the name palm thief. Although he is not averse to eating other types of food - the fruits of Pandanus plants, organic matter from the soil, and even their own kind.

The most ancient way of movement is walking or leisurely running, in which the animal rests on the entire surface of the feet and hands (or most of them). Therefore, this method of movement is called foot-walking. It is not particularly fast, but guarantees stability and maneuverability. When walking, at each moment of movement, only one limb is elevated, while the other three serve as a support and provide balance.

Sequentially rearranging the limbs of the left and right halves of the body, the animal moves forward. Stopigrade has been preserved in many insectivores: (hedgehogs, shrews), rodents (mice, voles, marmots) and some carnivores (bear). Almost the same as in plantigrades, the paws of animals climbing trees, such as squirrels, are arranged. Only their fingers are longer, and many have well-developed claws.

Finger walking and phalanx walking

But what about animals that live in open spaces? After all, they need to run fast in order to escape from predators or, conversely, to catch up with the victim. Of modern mammals, ungulate species with a special structure of the hand and foot are most adapted to running. But before such a limb was formed, as, for example, in antelopes or horses, their ancestors switched from relying on the entire foot to relying on the phalanges of the fingers, i.e., to toe walking.

On the one hand, finger walking allows you to develop greater speed, as well as move in jumps. But on the other hand, the area of ​​\u200b\u200bsupport on the surface of the earth decreases and the physical load on the phalanges of the fingers increases (it is easy to verify this by walking on tiptoe), which means that there is a risk of dislocating the fingers. Therefore, it is necessary to sacrifice the mobility of the joints for the sake of their greater strength: the phalanges of the fingers have become shorter, have lost mobility, and the bones of the metacarpus and metatarsus, on the contrary, have greatly elongated.

Among modern mammals, representatives of the group of carnivores, such as cats and dogs, are digitigrade. The effectiveness of this method of movement is evidenced by the fact that the fastest mammal on Earth - the cheetah, which develops speeds up to 110 km / h, belongs to digitigrade.

Why does a cheetah run fast but not for long?

Unlike digitigrade runners, hoofed mammals are able to run not only quickly, but also for a long time. This is possible due to the stronger structure of the limb and the presence of horny hooves. Ungulates rely on the very ends of the fingers, covered with hooves that protect against injuries on hard soil or stones. Therefore, the run of digitigrade carnivores is a combination of speed and maneuverability, and the run of their potential victims - herbivorous ungulates - is a combination of speed and endurance.

In land mammals, the hind limbs, as a rule, are always better developed than the front ones. For example, in hares, this difference is very significant. They usually move in short hops, pushing off with both front and hind legs. When running fast, hares make long jumps. During the movement, they carry their hind legs far forward relative to the front ones, which at this moment serve as a support for the body. The main load when running falls precisely on the hind limbs.

Ricochet run

Very rarely, the forelimbs are no longer used as a support in the process of running. A striking example of the "two-legged" way of moving by jumping are kangaroos. This method of movement is called ricochet running.

At the same time, pushing off with strong hind legs and using the tail as a rudder and counterweight, kangaroos are able to make huge jumps one after another, bouncing off the ground (“ricocheting”) like a tennis ball. Large species of kangaroos move in jumps 6-12 meters long, while developing a speed of up to 40 km / h. True, they cannot run at such speed for a long time and get tired quickly.

In 1847, Carl Gustav Bergmann, who worked at the University of Göttingen, formulated a rule that, in a simplified form, sounds like this: “In a warmer climate, warm-blooded animals of one or similar species are smaller, and in a colder climate they are larger.”

At first, the conclusions of the German biologist, anatomist and physiologist were received with doubt by the scientific community, but over time it became obvious that Bergman described one of the principles of evolution as precisely as possible.

Indeed, such a pattern not only exists, but is also clearly visible. For example, in an animal that has one of the widest habitats - a wolf. The Arabian wolf, which lives in Oman, Israel and other countries of the Middle East, is a skinny short creature weighing about 15 kilograms. Despite its size, it is a ferocious predator, a biblical symbol of malice and rage.

Northern woods wolf and Egyptian wolf (below)

In Alaska and northern Canada, there are wolves twice as large and five times as heavy. Wolves from the north of India, who raised Mowgli, hardly reached a weight of a quarter of a centner, but the beast on which Ivan Tsarevich rode would have pulled, if he really existed, no less than 60 kilograms, like a hardened wolf of the forest zone of Russia.

A similar situation with the cougar. The variation in weight among individuals living at the equator and in the south of Canada or Argentina is from 60 to 110 and even, in exceptional cases, 120 kilograms.

Changes are noticeable as you climb the mountains. The higher and, accordingly, the colder, the larger the animals. If we consider animals of closely related species, then Bergman's rule is even more obvious: the Malayan bear, whose average weight is 45 kilograms, is ten times inferior in weight to the average polar bear.

The polar bear is one of the largest terrestrial mammals of the order of carnivores. Its length reaches 3 m, weight up to 1 ton. It lives in the subpolar regions in the northern hemisphere of the Earth.

The Malayan bear is the smallest representative of the bear family: it does not exceed 1.5 m in length. It lives in India.

Want big differences? You are welcome! Mentally place next to the smallest southern deer, the kanchil from Sumatra, and the largest northern deer, the elk from Kamchatka or Alaska. The difference is simply fantastic: 25 centimeters at the withers and 1200 grams of weight for the first and almost 2.5 meters and 650 kilograms for the second. Such a comparison may not be very correct, but it is clear.

SAVE HEAT

What is the secret why animals grow as the climate gets colder? It's all about thermoregulation. The colder it is, the more important it is to retain body heat, to minimize heat transfer to the environment. After all, maintaining a constant body temperature requires energy, that is, ultimately, food. It needs to be mined, which means spending energy. Why waste it again?

At first glance, the larger the surface of the body, the more heat the living being loses. But it is pointless to consider heat losses by themselves - their relation to heat production is important. Animals not only lose heat, but also produce it, and the larger the volume of the body, the more joules it releases into the atmosphere.

Tiny kanchil deer and elk from Alaska

With increasing body size, the increase in volume outpaces the increase in surface area: in an animal that becomes twice as wide, taller and longer, the body area will increase by four times, and the volume by eight times.

Thus, the ratio of heat loss to its production will be twice as beneficial for the “grown up” animal. In reality, of course, everything is not so mathematically accurate, but the trend is just that.

Of course, as with any rule related to wildlife - that is, to the most complex dynamic systems of many components - there are exceptions to Bergman's rule. Their reasons can be very diverse.

From the scarcity of the food supply, which simply does not allow animals to "gain weight" and forcing them to become smaller, to the resettlement of animals outside their usual range. In such situations, the picture may not be "ideal" due to the fact that not enough time has passed.

Animals that migrated north or south have not yet evolved, because, like most similar processes, in warm-blooded animals, the change in size due to climate is quite fast by paleontological standards, but slower than you can see with the “naked eye”.

However, the largest animals - elephants, hippos, giraffes - live where it is very hot. And this does not contradict Bergman's rule. Extremely abundant food resources are available to such giants. And it would be strange not to use them - since you can eat up to a large size, which is pleasant in itself, and at the same time "bring" yourself out of the threat of predators who cannot cope with the giants.

But these animals are constantly at risk of overheating, since their heat production is huge - therefore, solving the problems of heat transfer, they have to go to all sorts of tricks. For example, sitting in the water most of the time, like hippos, or growing huge ears, like elephants.

POLE CLOSER - EARS SMALLER

Bergman's rule is rarely considered in isolation from another ecogeographical rule, the authorship of which belongs to the American zoologist Joel Allen. In 1877, Allen published a work where he drew the attention of specialists to the relationship between climate and the body structure of warm-blooded animals of related species: the colder the climate, the smaller their protruding body parts relative to its overall size.

Conversely, the warmer the climate, the longer the ears, tails and legs. Again, you don’t have to go far for examples: the fennec fox and the arctic fox. The desert fox is famous for its huge sail ears, while the fox has small ears, barely sticking out of thick wool in winter.

Arctic fox and fox (below)

Indian and African elephants live in a warm climate, and their relative the Siberian mammoth lived in the land of frost. The African elephant has huge ears, the Indian one is noticeably smaller, and the mammoth was completely undignified by elephant standards.

Regularities in the size of the protruding parts of the body are also associated with heat transfer. Through the tails, ears and legs there is an active heat transfer, so in the north or in the highlands it is beneficial to minimize their size. And we are talking here not only about the vain loss of heat, but also about how to keep the body intact. Long tails and large ears can simply freeze so that tissue necrosis develops - this sometimes happens with dogs that the townspeople bring to the tundra from places with a temperate climate. In such cases, the ears and tails of the unfortunate quadrupeds have to be amputated.

Indian elephant

And where it is warm, long-tailed and eared is the most suitable place. Since active heat loss occurs through these organs, they are not a burden here, but, on the contrary, a means of cooling the body, acting like a computer cooler radiator. Let's take an elephant as an example. Its large, vascularized ears receive blood.

Here it cools, giving off heat to the environment, and returns to the body. The same can be said about the processes in the trunk. We do not know, but only assume how energy-intensive it was for mammoths to own a trunk. The ancient animals were saved by the fact that the trunk was with a fairly solid fat layer and, like the rest of the mammoth's body, was covered with thick hair.

Are there any other rules describing the dependence of the appearance of animals on climate? In 1833, that is, before Bergmann postulated his rule, the German ornithologist Konstantin Wilhelm Gloger, who worked in Breslau (present-day Wroclaw), noticed that in related species of birds (and, as further observations showed, in mammals and some insects too), pigmentation is more diverse and brighter in warm and humid climates than in cold and dry ones.

Those who were lucky enough to get into the repository of the Zoological Museum of Moscow State University could see dozens of wolf skins hanging one after another. Reddish-brown no more than a meter long, fawn a little longer, gray even longer and, finally, huge, human-sized, almost white with a slight admixture of gray and black hairs. Red southern and white northern wolves are an example of Gloger's rule.

Another example is the pink starling, an inhabitant of warm countries, and the common starling, dark with light specks. At first, it was assumed that such a distribution was due to the need for camouflage: among the bright greenery with multi-colored flower petals, it is easy to miss the bird of paradise with its riot of colors in plumage, but the ptarmigan will be in full view.

Pink starling and common (below)

And the rainbow hummingbird will be just as uncomfortable in the tundra - and it is likely that even before it freezes, the bird will be in someone's teeth or claws. The masking version is still not denied, but it turned out that another factor is at work here: in a warm and humid environment, the synthesis of pigments proceeds more actively.

There is an interesting exception to Gloger's rule. This is the so-called industrial melanism, first discovered in England and then in North America. Butterflies that live in places with developed industry can serve as an example of it. Factories threw out smoke and soot, birch trunks and lichens darkened. White butterflies against their background became noticeable, they were eaten by birds.

Those insects survived who, due to a random mutation, turned out to be melanist (black). Gradually, the number of black individuals in the populations began to reach 90%, but once upon a time 99% were white.

Veniamin Shekhtman
DISCOVERY Magazine August 2014

The author, who is in love with his science - zoogeography, claims and proves that it is as interesting as everything connected with the life of animals in freedom. He talks surprisingly clearly about the biological properties of animals that help them exist in a certain environment, about the connections of fauna with plant formations, about the distribution of animals around the globe and about the factors limiting their resettlement, about the history of the development of fauna on various continents.

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Gloger's law. Already in the last century, zoologists noted that terrestrial animals living in areas with a humid climate turn out to be darker-colored than animals of the same or similar species inhabiting arid regions. This phenomenon was scientifically analyzed and formulated as a zoogeographical rule by Konstantin Albert Gloger, who published in 1833 in Wroclaw the book “Changes in birds under the influence of climate”.

The noted pattern turned out to be common for both vertebrates and invertebrates. Laboratory experiments with field crickets (Gryllus campestris) showed that when keeping crickets in a room where the relative humidity of the air was maintained at 60–80%, they acquired a rich dark color.

Birds turned out to be involuntary participants in such an experiment - medium-sized hawfinches (Munia flaviprymna) living in the desert interior of Australia. Several birds of this light-coloured desert species have been introduced to England and kept in captivity. After three years of living in the humid English climate, dark spots appeared on the plumage of birds, enhancing the resemblance of this desert species to a dark-colored close species, the hawfinch. munia castaneithorax, living in the humid coastal forests of Australia.

Later, this pattern was confirmed by many examples. The simplest of them: the variability of gastropods Arianta arbustorum and Succinea pfeifferi, living in Central and Eastern Europe, common frog (Rana temporaria) and viviparous lizard (Lacerta vivipara). Interestingly, American moles Scapanus in the states of Washington and Oregon they have black fur, in Northern California, where the climate is drier, they are brownish, and in Southern California, where it is still drier, their fur is light, silvery. This biogeographic regularity is called Gloger's law.

The color and intensity of the color of the outer integument of animals depend on the amount of pigment - melanin, and not only the humidity of the air, but also the temperature of the environment influence its formation. Low temperature causes a lightening of the color, high temperature, on the contrary, darkening. The cumulative effect on the body of an animal of both these factors (humidity of the environment and its temperature) just gives the resultant effect that we usually observe. In some cases, there are exceptions to Gloger's law caused by different combinations of humidity and air temperature. So, the wool of wolves from Belarus has a lighter, ashy color than that of wolves from the Pyrenees - rather dark, with a brownish tint.

Temperature. Ambient temperature is a powerful factor that influences and often determines the distribution of living organisms on earth. Temperature fluctuations on land, including the temperature of the soil surface, have a very wide range - from +80° to -70°C. And in the oceans, it is almost 5 times less: from + 30 ° to -2 C.

Temperature changes on land can sometimes be very rapid. Some natural areas are characterized by a change in ambient temperature by several tens of degrees during the day. Such temperature contrasts do not know the aquatic environment.

In terrestrial animals, in many cases, a profound differentiation of organisms has developed according to their requirements for the thermal conditions of their living environment.

Animals are stenothermic and eurythermal. Each species of animal has its own range of temperatures most favorable for life, which is called the temperature optimum of this species. This temperature range, that is, the limits of the temperature optimum, can be relatively wide in some species, while in others it covers only a few degrees. If the temperature optimum for any species is narrow and the normal vital activity of the organism is disturbed when it goes beyond this temperature limit, and also if the animal does not tolerate fluctuations in environmental temperature, then this species is called stenothermal.

On the contrary, animals that successfully exist in a wide range of environmental temperatures, that is, having a temperature optimum of a large variety of indicators, are called eurythermal species. They usually do not die, even if they have to exist for some time in conditions that go beyond the temperature optimum.

There are relatively more stenothermic organisms in the ocean than on land. Among the stenothermic species, cold-loving or oligothermal species stand out, such as, for example, the polar bear and the musk ox; heat-loving, or polythermal (giraffes, apes, termites, etc.), and animals that require a moderate but constant temperature of the environment for their existence. There are few of them in general.

Eurythermic species are most characteristic of temperate latitudes, where the seasonal contrast of living conditions is well expressed. Eurythermal organisms are characterized by a wide distribution. For example, the species range (region of geographical distribution) of the common toad (Bufo bufo) extends from northern Africa in the south to Sweden in the north, where this amphibian is found as far north as Stockholm. And on the North American continent, another type of toad (Bufo terrestris) found in the area from Florida to Hudson Bay. The wolf, weasel, ermine and many other mammals and birds living both in the tundra and in the steppes and hot deserts have a no less extensive range.

If in any natural zone an isolated area appears with a special climatic regime resembling the conditions of another zone (for example, with a warmer microclimate), then such a place can be inhabited by animals that are not characteristic of this zone. This is how the "outposts" of the southern fauna appear, pushed to the north and resembling "islands" of southern species, the temperature optimum of which does not correspond to the natural zone. Such an "island" of thermophilic fauna was found in Germany, in the vicinity of Freiburg, in the southwestern corner of the Black Forest. In Poland, there is a similar "island" in the vicinity of Krzyzanowice, in the Nida valley.

The biological effect of high and low temperatures is different. At a temperature of about 55 ° C, proteins in the protoplasm of cells coagulate and most animals die. Low temperatures do not cause protein clotting, so many animals have adapted to endure low temperatures, hibernating or in a deep anabiotic state, after which, when favorable conditions occur, they are able to return to active life again.

The reaction to temperature differs significantly in the so-called cold-blooded and warm-blooded animals.

Cold-blooded animals. The cold-blooded, or, as scientists say, poikilothermic, includes the vast majority of animal species: all invertebrates and lower vertebrates, up to and including reptiles. The body temperature of cold-blooded animals is close to or equal to the ambient temperature and changes following the changes in the latter. A cold snap occurs - and the body of a cold-blooded animal becomes colder. When warming, the body temperature rises. In deserts, maximum body temperatures close to 50 °C have been noted in young praying mantises (genus Mantis) and grasshoppers moving on the sand, the temperature of which reached 50.8 °C.

In insects wintering in temperate climates (for example, in Poland or in Central and Eastern Europe in general), the body temperature (or pupae and eggs) is close to 0 °.

Most cold-blooded animals prefer warm climates, and most of them live in the tropics. If we conventionally divide the earth into a cold zone, temperate and hot, then the number of arthropod species would correspond accordingly in them as 1:4:18.

In cold-loving and heat-loving species of butterflies from the family Syntomidae in these belts there are even more expressive ratios - 1:3:63. This pattern is also characteristic of scorpions, spiders, centipedes and even reptiles. So, in Poland, on an area of ​​312 thousand square kilometers, eight species of reptiles live, and on the island of Java, with an area of ​​only about 132 thousand square kilometers, 122 species are known.

It is easy to understand this pattern. In a warm climate, cold-blooded animals lead an active life throughout the year, while as they move to colder regions, the time of manifestation of their active life is increasingly limited by a shortening of the season of favorable temperatures, and winter, the beginning of spring and the end of autumn become a period of long rest (hibernation, diapause, anabiosis).

The intensity of metabolism in the body of an animal is in complex dependence on the ambient temperature. It is believed that the rate of biochemical processes increases by 2–3 times with an increase in temperature by 10 °C. This refers, of course, to changes in temperature in the range of normal indicators, well tolerated by this type of animal. The dependence of the rate of metabolism (metabolism) on the ambient temperature can be investigated experimentally.

It has been established that the larva of the flour beetle (meal worms) at an ambient temperature of 15 ° C consumes 104 cubic centimeters of oxygen in one hour in terms of one kilogram of body weight, at 25 ° C - 300 cubic centimeters, and at 32.5 ° C - 520 cubic centimeters.

Acceleration of the metabolic process shortens the time for the body to pass through the stages of individual development, shortens the duration of the ontogeny stage. Before the start of metamorphosis, the larvae will need a different time, depending on the temperature at which they were kept before.

The rate of passage of the pupal stage by the flour beetle (from the moment of pupation to the exit from the pupa of the imago beetle) depending on the ambient temperature is presented in the table:

Temperature in degrees C	13,5	17	21	27	33
Time in hours	1116	593	320	172	134

From this experience it can be seen that an increase in the temperature of the environment by about 20 ° C caused a reduction in the duration of the pupal stage by more than 8 times, that is, development was significantly accelerated.

Under natural conditions in the temperate climate zone, the rate of individual development of many invertebrates is low, winter causes a long period of depression in vital activity, and as a result, the number of generations that appear in one year is small here - often one or two.

In a hot climate, the rate of individual development of invertebrates is often higher, periods of depression are shorter or absent altogether in some natural areas, and, accordingly, several, and in some species even more than ten, generations can be produced during the year.

To illustrate this pattern and to clearly imagine the potential for reproduction of invertebrates in a hot climate, we will calculate the size of the offspring of some conditionally taken, even fictional, insect species, for example, represented only by females that reproduce parthenogenetically, that is, without the participation of males. And such species exist in nature!

Developing in the most favorable conditions, in the optimum, which is located for cold-blooded animals between the tropics, they reach their largest sizes here. Tropical centipedes reach a length of 15 and even 20 centimeters with a thickness of a finger, while the largest centipede from temperate latitudes in Europe is no more than 4 centimeters in length. Skolopendra from equatorial countries are of gigantic size, up to 27 centimeters long, and in Yugoslavia their maximum length is 8-10 centimeters, but in Poland they are no longer found at all, only kivsyakov can be found there (Lithobius).

And this is a direct influence of climatic conditions. The cold-blooded animals of the tropical regions of America, Africa and Asia are similar in size and appearance, although their species are usually different on different continents.

Here are some more examples of the same pattern. Several species of scorpions are found in Europe, but the length of individuals of any of these species almost never exceeds three centimeters. More species of scorpions live in low latitudes, while the absolute superiority among them in size belongs to the imperial scorpion. (Pandinus imperator) covered with black armor and reaching 18 centimeters in length from the front edge of the shell to the poisonous spike at the end of the abdomen. Such "emperors" live in West Africa.

Tropical butterflies and beetles provide wonderful examples of gigantism. Suffice it to recall the Brazilian butterflies, many of which have a wingspan of more than 20 centimeters, the Hercules beetle (Dynastes hercules) 15 centimeters long or huge bugs from the family Belostoma, outwardly a bit like a water scorpion (nepa) living in our European reservoirs, but 10 centimeters longer than it. No less striking than the Hercules beetle is the West African goliath beetle. (Goliathus giganteus), although it reaches a length of only 10 centimeters. But he has terrible ticks the size of a third of the length of the body, formed from two horns: one on the head, and the other on the first segment of the cephalothorax.

In the tropics there are large gastropods from the family Achatina, having shells up to 17 centimeters long and weighing more than 500 grams.

No less vivid and abundant examples are among the cold-blooded. Let us recall the crocodiles that inhabit mainly tropical water bodies, huge snakes - pythons, boas and anacondas. In the tropics, very large poisonous snakes are often found: for example, spectacled snakes - cobras (Naja) in Asia or scary African vipers (Bitis arietans and Bitis gabonica).

American iguanas are large in size (family Iguanidae), resembling our lizards, and monitor lizards (family Varanidae), inhabiting Africa and the hot regions of Asia. The body length of many species of monitor lizards and iguanas often exceeds one and a half meters. The largest living monitor lizard is the Komodo dragon. (Varanus komodoensis), inhabiting two small islands in Indonesia between the islands of Sumbawa and Flores; these are real monsters of three meters in length with a heavy body and powerful limbs.

Warm-blooded animals. Only birds and mammals have warm blood. Complex physiological mechanisms allow them to maintain a constant and fairly high body temperature. In different species of birds and mammals, body temperature is not the same, but always mostly in the range from 30 ° C to 44 ° C. In a healthy animal, temperature fluctuations usually do not exceed half a degree. The exceptions are the Australian platypus and echidnas, whose normal body temperature is lower than that of all other mammals, and is only 3 ° C. To many features of primitiveness characteristic of these ancient mammals, some dependence of their body temperature on ambient temperature is added, which is expressed in a wider range of temperature fluctuations, reaching 4 ° C both above and below the average norm, and which makes them related to reptiles. .

To maintain a high and constant body temperature, the animal body expends a large amount of energy, which, in addition, is spent on thermal radiation. Therefore, warm-blooded animals must have an intensive metabolism and lead an active lifestyle, that is, consume a lot of food and absorb it quickly, and these processes, in turn, are facilitated by high body temperature.

Warm-bloodedness is an invaluable property of animals, acquired in the process of organic evolution, which opened up for them vast living spaces of temperate and polar latitudes and high mountains, which are not accessible to most species of cold-blooded animals. The polar margins of the continents, the islands of the Arctic and even floating ice floes serve as an arena of active life for birds and mammals.

In temperate zones in both hemispheres of the Earth, snowy and cold winters, and in this harsh season for animals, warm-blooded animals literally reign here. They lead an active life, and some species, such as our crossbills, even breed and are able to feed chicks, while cold-blooded animals survive a period of low temperatures, being in an inactive or even anabiotic state. That is why, in the composition of the fauna of areas with a cold climate, birds and mammals make up a relatively higher percentage in terms of the number of species than in the tropics.

However, winter is also a difficult season for warm-blooded animals. Think about it, because the difference between the temperature of the body of an animal and the environment, even in Central and Eastern Europe, for example in Poland, can sometimes reach 75 ° C. This causes enormous heat loss in living organisms and turns into a "to be or not to be" problem.

In the system of thermoregulatory mechanisms of the body of warm-blooded animals, an important place belongs to the outer integument of the body, which has a heat-insulating function. This is easy to see for yourself. In birds living in cold regions, under the covering feathers, the layer of warm, delicate down is much more significant than in the inhabitants of the south. In addition, in the north of our hemisphere you will not meet birds with bare heads and necks, such as vultures, vultures and cassowaries. The coat of mammals also consists of two layers: guard hairs and a thick down under them. The density and thermal insulation properties of the down are directly related to the characteristics of the environment and life. And here is an example that can be seen in the zoo. Take a look at the Himalayan (Helarctos tibetanus) and Malay (Helarctos malayanus) bears. These are related species. They are similar in appearance. But the Himalayan bear looks like a "stack of wool", because it is a resident of the cold highlands, and the Malayan has a smooth, low, velvety coat, like many animals in the tropics.

The difference in the features of the coat is well expressed even within the same species. The Ussuri tiger has to roam in deep snow, and its whole body is covered with long and fluffy hair, which is especially long on the nape and on the chest. And the Bengal tiger is overgrown with short smooth hair, almost completely without down.

It is known that even the cost of furs (for example, foxes and skunks) is affected by the area from which they are mined: the skin is more expensive the further north it is mined.

Only in the tropical zone in a warm climate are animals covered with sparse hair or completely hairless: hippos, rhinos, elephants, and some types of buffaloes.

Bergman's law. The coat of mammals, especially thick and lush in high latitudes, and the plumage and warm down of birds protect the animal's body from hypothermia. However, the problem of thermoregulation is not completely solved only with the help of various adaptations of integumentary tissues.

In 1847, a study by the German zoologist Carl Bergman “On the connection between the economy of heat in animals and their size” was published in Göttingen. Karl Bergman drew attention to the fact that animals - inhabitants of cold climates - are usually larger in size than individuals of the same species living in warmer climates. This is not an accident, but the result of a vital adaptation of animals, based on a simple mathematical pattern. After all, heat loss occurs through the surface of the body, and the larger this surface relative to the volume of the body, the greater the heat loss. And larger organisms have a relatively smaller surface area per unit of weight (mass).

If, for example, we take a cube with a side of 1 centimeter, made of a substance with a specific gravity of 1 g cube. cm, then the total surface area of ​​all six faces will be 6 square centimeters, and the volume will be 1 cubic centimeter, that is, a mass of 1 gram. When calculating the surface of a cube per unit mass, we get 6 square centimeters / gram.

If you then take a cube with a side of 2 centimeters, that is, twice as large, then the surface of six faces will be 24 square centimeters, and the volume will be 8 cubic centimeters and, accordingly, the mass will be 8 grams. When calculating the surface area per unit volume or mass, 3 square centimeters / gram is obtained. So, for a cube that is twice as large in volume, the relative surface turned out to be half as large.

In the language of a biologist, this pattern means that an animal with twice the size gives off half as much heat per unit body mass (naturally, other things being equal). Therefore, a larger animal, giving off relatively less heat per unit weight, can consume relatively less food than a small animal. This means that with a limited food supply, a larger animal survives more easily than a small one.

This pattern is the essence of Bergman's zoogeographical law. Examples confirming it are numerous in all parts of the world. So, for example, wild boars from Southern Spain have an average skull length of 32 centimeters, in Poland - about 41 centimeters, in Belarus - 46, and in Siberia there are huge boars with a skull length of 56 centimeters. Changing the size of animals in accordance with Bergman's law can be observed in hare, roe deer, foxes, wolves, bears and other mammalian species. In the expanses of Europe, these animals become smaller towards the southwest and, on the contrary, increase towards the north and east in those areas where winters are more severe.

Geographic size changes in birds also follow the principles of Bergmann's law. For example, horned larks (Eremophylla alpestris), living in North America clearly demonstrate this pattern, as can be judged by changes in wing length: larks from the shores of Hudson Bay have a wing length of 111 centimeters, birds from Nevada have 102 centimeters, and on Santa Barbara Island, off the coast of California , - only 97 centimeters. Subspecies of animals from cold regions usually outnumber those from lower latitudes with warmer climates. For example, the European blue kingfisher (Alcedo atthis ispida), a beautiful bird widely distributed along small rivers, but not numerous everywhere, turns out to be the largest bird in comparison with other subspecies of this kingfisher: Alcedo atthis pallida- pale blue kingfisher inhabiting Syria and Palestine, and Bengal Alcedo atthis bengalensis- the smallest of the blue kingfishers living in India and Indonesia. Likewise, the European Oriole subspecies (Oriolus oriolus oriolus) noticeably larger than the oriental oriole (Oriolus oriolus kundoo) from Afghanistan and the central regions of India.

In the southern hemisphere of the Earth, on the contrary, the increase in the size of animals occurs towards the South Pole, that is, also in accordance with the principle of Bergmann's law: the size of animals in a colder climate increases. And here is an example from the southern hemisphere. On the Galapagos Islands, in the tropical zone, lives a small penguin - spheniscus mendiculus 49 centimeters tall, to the south, from the islands of Tristan da Cunha to Tierra del Fuego, that is, in a temperate oceanic climate, a larger penguin lives - Eudyptes cristatus, whose body length reaches 65 centimeters. Further south, up to 60 ° south latitude, the penguin is common. pygoscelis raria, reaching 75-80 centimeters. On the coast of mainland Antarctica lives a huge emperor penguin - Aptenodytes forsteri height 120 centimeters and above.

If two relatively closely located territories have similar faunas, but differ in average temperatures, that is, one of them is colder, then it is on it that the average size of both mammals and birds will be larger. And here are examples of such pairs of faunas. On the south coast of Australia, the average annual temperature is 16 ° C, and on the coast of Tasmania 11 ° C. And this is already enough for all Tasmanian platypuses, echidnas and kangaroos to be larger than Australian ones. A similar pattern can be seen in New Zealand. The North Island of New Zealand is warmer than the South Island. The average annual temperature in the North is 16.6 °C, and in the south 10.4 °C. And accordingly, parrots and kiwis are larger in the South Island, and not in the North.

From the rule discovered by Bergman, there are exceptions that can be understood and explained in each specific case. On the one hand, these are migratory birds, which, even if they nest in the north, in the northern hemisphere, are still not affected by the Arctic cold, as they quickly complete the breeding season and move to warmer climes. Migrating, they are always in more or less favorable conditions.

Another example is represented by small mammals: voles, mice, shrews, which spend most of their time in the specific microclimate of their burrows, which is more or less stable and often milder than the climate of the surrounding area. Active in winter under a layer of snow, they are in conditions significantly different from those that prevail over a snow-covered plain, since snow has a great thermal insulation effect. And in the center of Alaska, the distribution of temperature at different heights and under snow was studied. The snow cover was relatively thin - 60 centimeters. There were severe frosts. The thermometer showed -50 °C, and under a layer of snow on the soil surface, frost did not reach even -7 °C. And under these conditions, gray voles (genus mucrotus) led an active life and moved freely in their snowy passages, although their fur coat is thin, and their feet on their paws are not covered with wool at all. At the same time, the caribou were having a hard time surviving these severe colds. Thus, it can be said that these two species of mammals, being in the same geographical point, existed in completely different climatic conditions, as if their habitats were separated from each other by tens or hundreds of miles.

Laboratory experiments also confirm the pattern noted by K. Bergman. White mice, kept from an early age at a low temperature of only +6 ° C, grew much larger than those that were in the same period of time under conditions of an average normal environmental temperature of +26 ° C. The same experiment was carried out with no less success on chickens. And since then, the method of "cold education" of chickens has been widely used in poultry farming to increase the industrial yield of meat products.

Allen's law. For animals - inhabitants of the cold regions of the Earth, it is advisable to reduce the surface of the body relative to its mass. This is achieved in two ways: by increasing the overall size of the body and reducing the size of all prominent organs and parts of the body: ears, muzzle, legs, tail. Polar animals have shorter ears, tails, muzzles than animals inhabiting areas with a temperate and especially hot climate. Even the paws and necks are shorter and thinner in polar animals. This phenomenon is called Allen's law.

The most common example of Allen's law is the comparison of the arctic fox (Alopex lagopus) with short ears and muzzle, undersized, with a small tail and our red fox (Vulpes vulpes) taller and more graceful. Likewise for the white hare (Lepus timidus), living in the north, the ears are shorter than those of a brown hare (Lepus europaeus), widespread to the south. It is worth comparing the reindeer with the red deer to make sure that the former has shorter ears and shorter legs.

Allen's rule is also confirmed in the laboratory, where mice kept in cold conditions have shorter ears and feet, while those grown at elevated temperatures are longer than normal. The length of the legs in chickens in the experiment also turned out to be dependent on the temperature of the environment.

From Allen's law, the conclusion logically follows that an animal with a particularly large relative body surface should live only in low latitudes, in the tropics and subtropics. Long-eared fennec foxes live in hot climates. The African savannas are home to the long-legged giraffe, no less famous for its exorbitantly long neck, and the small, graceful gerenuk antelope. (Lithocranium walleri).

The same pattern is clearly seen in the example of bats. Flying dogs, or flying foxes, belonging to the suborder of large fruit-eating bats (Megachiroptera), have a huge wing surface, and they are common only in the tropical zone. Suborder of smaller fruit-eating bats, microchiroptera, consists of 16 families. Representatives of 13 families live in tropical and subtropical zones, and only bats from the remaining three families were able to settle down to temperate latitudes. Horseshoe bats are the most common in Central Europe. (Rhinolophidae) and leather jackets (Vespertilionidae).

Minimum rule. In the fifties of the last century, the German chemist Justus Liebig became interested in plant life, fertilizers and laid the foundations of the science of agricultural chemistry. At the same time, he formulated the rule according to which the factor limiting the development of a plant is an element that is at a minimum, that is, one that the plant may lack. For example, if a plant is given the necessary for its life and even more nitrogen, phosphorus, iron and all other necessary elements, but at the same time one element, potassium, is given less than the required norm, then the plant will grow stunted and undersized. Its growth will be limited by a lack of potassium.

Liebig's minimum rule applies equally to plants and animals. If an animal or a person is given food without vitamin C, they will get scurvy, even if the food is plentiful, refined and tasty. The state of the body in this case also determines the factor that is at a minimum or is completely absent, like vitamin C mentioned in our example, and not the factors that are in excess. If a rat is kept on a protein-free diet, then it will grow poorly, remain small and frail, and soon die altogether, despite the fact that it will be given plenty of carbohydrates, and fats, and vitamins, and trace elements.

The minimum rule is subject not only to plant and animal organisms, but also to groups of animals, populations, species and biocenoses. Any of the environmental factors can limit the development of a population or any biocenotic relationships, if it is present at a minimum.

Knowing this rule allows you to effectively apply it in hunting and forestry.

The number of gray partridges is limited primarily by the lack of food in winter and the impact of predators on them. Therefore, in order to increase the number of partridges in the hunting economy, it is necessary not so much to limit their shooting and import dozens of individuals caught in other places, but to organize bird feeding in winter and make plantations that include dense clumps of shrubs in which partridges could hide from predators.

As for small insectivorous birds, they are mainly provided with food in natural conditions. The factor limiting their numbers is often the lack of places suitable for building a nest. Therefore, with the help of artificial nesting sites (hollows and birdhouses) and planting artificial plantations, you can quickly increase the number of useful songbirds.

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