Length of a body of a squirrel fluctuates from 16 to 27 cm. Slender body. Standing, quite large ears, being unbent forward, close eyes. Width of ears is equal in the middle 0.75 of their heights. On the rounded-off tips of ears the brushes of hair which are strongly expanding in the winter grow. Shorter and weak forepaws with four long, mobile fingers, are armed with the long, squeezed from sides, bent claws. The thumb is underdeveloped and presented by a small hillock with the flattened claw. Hind legs are longer, with five fingers. Claws of hinder legs are less bent well than lobbies. Soles in the summer partially naked, for the winter acquire dense fur. On stupnyakh forepaws there are five naked callosities, on back — four. The tail exceeds a half of length of a body, is densely covered with wool. Hair on each side of a tail reach considerable length, in 30 — 60 mm why the tail has the flattened form.
The lower cutters are strongly squeezed from sides; in the top jaw of adult small animals five molars (together with lozhnokorenny), but the first lozhnokorenny tooth is underdeveloped and has an appearance of a thin stick.
Coloring of squirrels is very changeable, and the seasonal dimorphism at them is strongly expressed. The prevailing coloring of summer fur at the small animals inhabiting the European part of the former USSR except the Carpathians, and Western Siberia, red, and at small animals from the Carpathians, Eastern Siberia and from the Far East — mainly brown or almost black. In the winter in coloring of the European and West Siberian squirrels prevail gray and silvery tone, with brown shades, and the ridge happens quite often red or as pushnik speak, "gorbolysy". At small animals from Eastern Siberia and from the Far East in winter coloring of top prevail dark-brown and dark gray tone. A body bottom from a chin and almost to the tail basis, and also internal surfaces of legs during the whole year remain white.
On variability of coloring of fur of a squirrel from the same area can be reduced to three the most often found types: 1) krasnokhvostka, 2) burokhvostka and 3) chernokhvostka. In steppe pine forests on the plain of Western Siberia the serokhvosty form of squirrels meets. Among squirrels the general pobeleniye of fur (full or partial albinism) is sometimes observed, but also — emergence of white spots that leads to skewbald coloring.
The squirrel fades two times a year, except for the tail fading only once in a year. The spring molt proceeds mainly in March and April, and autumn — in September and October. The first molt begins now after rutting, but its terms strongly hesitate and stretch depending on fodder and weather conditions of this year. In days of good harvests of forages begins and comes to an end earlier, and in bad strongly is late and stretches. At females passes quicker and comes to an end by the time of the birth of young people, at males begins a little earlier and drags on till July. The molt begins with the head, in eyes and a nape, and then extends to cheeks and a forehead. Goes down from a nape on a neck to the area of shovels and a back, extending along ridge. The inner side on linny places becomes lead-black or blue, with strong impurity of the red tones depending on yellow dye (pigment), skoplyayushchegosya in hair bags. Later covers sides and legs. On the head long remain not faded a nose and ears. The last the trunk site at a root of a tail and the tail from the basis to top fades. Tail hair begin to drop out very much early (at Moscow region squirrels long before the beginning of the general molt — at the end of December), and only to the middle of summer the molt of a tail comes to an end, and almost all underfur, considerable part of an awn instead of which a little new grows drops out; the tail becomes very rare. Soon after that growth of new fur begins.
After the termination of a spring molt begins autumn which proceeds in strictly return order — from a tail root to the head. Growth of a new winter hair begins with the middle of summer. Males begin to fade at the end of the last autumn techka. Females fade after autumn childbirth, and those from them which had no second dung, fade earlier. Young small animals fade in the fall, a little later old males, almost along with yalovy autumn females.
On snow of protein leaves prints of all four paws: ahead two smaller lobbies which are strongly pulled together imprint two big back, behind. The trace of back pads is pulled together by heels, and lobbies — fingers. Total length of a trace is about 11 cm, width — about 7 cm.
The squirrel jumps moves, and poles of its traces last on snowdrifts under trees and bushes and with hemp on penek. Where protein is a lot of, sometimes their traces merge in the real tracks. The squirrel often digs out snow, getting on the earth mushrooms, berries and cones and nuts which fell or dumped by crossbills and woodpeckers. Except a characteristic trace on snow, it is easy to notice presence of a squirrel at the wood on the cones and the sheared trailer escapes of coniferous trees which are eaten around by a small animal. In days of a crop failure of wood seeds of protein often digs the earth, digging out mushrooms — cervine truffles which are known at hunters under the name of "parg", sometimes stocks from mushrooms on branches of trees. She chews tips of fir-tree branches, eats away flower kidneys, and throws branches on the earth, covering with them the soil or snow under a tree. Husks ripe cones of coniferous trees entirely, tearing off scales and absolutely clearing a core whereas at cones, rasklevanny woodpeckers and crossbills, scales remain on a core and are only moved apart and broken.
The area of a red squirrel as inhabitants of the woods covers all northern forest spaces of Russia from wood border to steppe areas in the south in the north: she lives in all woods of the European part of the country, and also in all woods of Siberia, the Far East and Kamchatka
On huge space of the area the red squirrel forms a row of the geographical races or subspecies differing mainly in coloring of fur and insignificant deviations in sizes.
The squirrel is one of typical wood inhabitants, especially coniferous forest. The small animal carries out the most part of life on trees. In the north at the removements the squirrel quite often reaches the forest-tundra and tries to arrange nests for the winter among a light forest, but perishes from a beskormitsa, frosts and predators.
In the wood of the place of its dwelling are very different and change by years and seasons of one year, mainly depending on a harvest of forages. In the spring and in the summer the squirrel adheres to a long-boled, dense and many-tier, damp coniferous forest, with a good underbrush, in a remote taiga, on valleys of streams and small rivers where the soil is usually a little boggy. During other seasons of year, depending on a harvest of seeds of coniferous trees, mushrooms and partly berries, the small animal keeps that in cedar forests and fir groves, in deciduous young growths or plantings of a fir. At an identical harvest of seeds the squirrel prefers the cedar and listvennichny woods. In pineries it meets less often; there it is attracted not so much by cones how many a harvest of mushrooms. The exception is made by the teleduck and other southern squirrels living all the time in pineries or the deciduous woods.
All warmer part of year of protein it is very active and the whole days runs on branches or on the ground, collecting a forage. Only in the middle of winter the deep snow covering the earth and friable snow hung on branches complicate movements of a small animal, and in hard frosts squirrels get into nests and spend some time in a semi-drowsy state there. At the end of January or the beginning of February of snow on branches happens less, the sun warms stronger, and the squirrel starts active life over again. Small animals day by day depart from a nest further and further, at males testicles, and in February — March, depending on weather conditions and fatness of small animals strongly bulk up, the techka begins. During a techka about one female gathers five or six males; small animals quickly run one after another on trees and on the ground, lift fuss and fights. The marriage period borrows about two or three weeks, and pairing of certain squirrels happens usually within 1 — 2 days, at the end of a techka. Days for 20 before childbirth the female begins to build one, two or three nests are more often, choosing dense plantings of coniferous trees.
The squirrel suits a nest or in hollows of trees, training wood lichens, a grass, a mochala, dry leaves and other soft laying there, or, more often, builds it of dry branches, a moss, trailing lichens, a lime mochala, etc., in a fork of a tree or among dense boughs, usually from the South and southeast side of a trunk, at the height from 7 to 15 m. Such spherical nest is called "gayno". Males, as a rule, do not build new nests, and borrow and correct thrown by a female or complete nests of thrushes, forty, hawks-perepelyatnikov, crows.
For a conclusion of children the female builds gayno more accurately and the big sizes, spending for construction usually from 4 to 5 days. The squirrel begins to build it from the basis, stacking and weaving thicker branches; then builds sides and a roof, leaving one or two exits. Inside the small animal covers a nest a soft laying. In hard frosts gayno well holds heat as the squirrel stops up with soft lichens all exits. The sizes of the internal room of a gayn fluctuate from 12 to 16 cm, and width of entrances from 5 — 6 to 8 cm.
For the 35th day after pairing at a squirrel, depending on age and fatness, 3 — 10 naked blind baby squirrels will be born, about 8 g everyone is powerful. Baby squirrels quickly enough grow, being put on weight on average on 1,5 g a day. From the eighth day of life skin at them begins to become blue and gradually becomes covered by hair; weeks through three are cut cutters, and approximately for the 30th day eyes open. By the same time baby squirrels begin to climb. At the age of about two months young people pass to independent food with wood seeds, nuts and berries and then leave a female. On the fifth month of life at baby squirrels change of young teeth comes to an end, and small animals become almost adult individuals. Having brought up the first dung, the female is a little fattened and usually again copulates. Thus, the squirrel usually brings two dung a year, and sometimes even three. Sometimes the last dung of a squirrel strongly is late, and the baby squirrels who were born late fall or even in the winter freeze.
The food of a squirrel is very different, and her players are changed by years and seasons. The bulk of food of a small animal is made by seeds and nuts of coniferous trees: a cedar, a larch, a fir-tree, a fir and a pine which the squirrel eats all year. In the summer to this forage berries and mushrooms increase. In more southern areas where the oak woods with an underbrush from a filbert grow, the squirrel eats acorns and hazelnuts. Besides, she eats insects, bird's eggs and baby birds, getting them in nests. In days of a crop failure of coniferous seeds, berries, nuts and mushrooms of protein passes to food with young escapes and buds of trees, bark, a bass and spongy wood mushrooms. In bumper-crop years of protein stocks nuts and cones, training them in hollows or burying among roots, and also dries mushrooms, hanging out them here and there, on branches of trees and bushes. The warehouses the small animal, povidimy, quickly forgets and finds them in the winter incidentally, examining all suitable places.
In ancient Russian records there are instructions on big removements or migrations of squirrels. They are observed almost in all parts of the country where the squirrel lives. Sometimes summer migrations are caused by a drought and wildfires, especially in the central and Eastern Siberia, but is more often a crop failure of its main forages — seeds of coniferous trees and nuts. Removements of squirrels present or short transitions from planting of one breed to planting another, from one forest area in another, or long and distant resettlements on hundreds of kilometers; the last are, povidimy, only in the woods of plains, extensive and monotonous on structure. The wandering squirrel can pass long distances; absolutely exact data on transitions to 250 — 300 km are known, but probably it passes considerably big spaces. There are with a speed of a step of the person, 3 — 4 km/h, but as long can move so — it is unknown. During migrations often comes out of the wood on open spaces of the tundra, steppes, on the opened fields, goes through naked tops of mountains, through the cities and villages, tries to cross the wide rivers as Northern Dvina, Ob, Yenisei, Amur, floats through the Gulf of Finland, Mezensky gulf, Taz Bay, Lake Baikal, Strait of Tartary. At the same time small animals in hundreds and in thousands sink, perish for hunger and freeze in the winter on open spaces.
Migration begins usually with the movement of certain small animals and then carries away all squirrels living in this area.
There is a squirrel the wide front one by one, but in one direction, without forming considerable solid packs. It Skoplyatsya only about big obstacles: on coast of the big rivers, gulfs, before steppes. During migration loses almost any care and does not pay attention to presence of people, dogs and to unusual noise of plants and big cities. Submitting to old habits, small animals during the course gather mushrooms and hang up them on a branch to dry, hide nuts and cones in hollows and among roots. Removements continue sometimes during one — two months, the whole summer and fall, to deep snow and hard frosts are sometimes observed, and occasionally happen within several years in a row to breaks in the winter. From the area with adverse conditions (a crop failure of forages, a drought, extensive wildfires) of protein spreads extensively, but the movement on the North is more often noticed. In this direction usually there are squirrels who bred in a forest zone. Having reached the forest-tundra and the tundra, they perish; reverse motion from the forest-tundra was not observed.
Irrespective of migrations the quantity of squirrels in the same area does not remain to constants from year to year and is subject to fluctuations which are connected with a harvest of seeds of coniferous trees. In more southern and western regions of the country where harvests of these seeds repeat more often and more evenly, according to a thicket the number of a squirrel, sometimes very strongly increases. Increase in quantity of squirrels, or, on the contrary, sharp reduction cover them quite often huge spaces in hundreds of thousands of square kilometers whereas migrations give only some regrouping of herd of squirrels on rather small sites, on the area no more than several hundred kilometers. The crop failure of a squirrel depends on the suppressed, reduced reproduction and on development of general diseases, the epizooty connected with starvation of small animals owing to a crop failure of the main forages.
Epizooty usually arises at the end of fall and most develops in the spring, and the reduced reproduction and small number of squirrels are observed usually in a year after a crop failure of forages, i.e. during the next trade season, and quite often fall on a year rich with sterns.
As a rule, sharp rise in number of squirrels is also late for one year after a year, fruitful on forages. The cones which are brought down on the earth by wind and crossbills serve as a rich forage to proteins all winter, spring and even the summer following after bumper-crop year. Provided with a plentiful stock of forages, squirrels well and quickly breed, bringing many young people in each dung. Very often squirrel harvest is necessary for a year with a crop failure of forages again, and proteins perish masses again or otkochevyvat to areas with a forage harvest. What diseases ruin protein in the conditions of an autumn and winter beskormitsa, it is not found out yet.
Squirrels, just as chipmunks, gophers, water rats, muskrats and other rodents, are subject to diseases of a tulyaremiya. Cases of death of squirrels from an infectious disease — a hemorrhagic septitsemiya were observed, and her diseases of a piroplasmosis widespread among pets and small rodents are possible. Adult squirrels and especially baby squirrels in nests suffer from ticks and fleas.
The squirrel is a valuable fur animal, one of the main objects of fur trade in Russia. It is got generally in a taiga zone of the European part, the Urals and Siberia. The bulk of squirrels arrives from Siberia, Yakutia and from the Far East. At the time of the Soviet Union, by the number of preparations this small animal conceded only to a sable, but now reception of skins was practically reduced to zero. In 2009 at the main Russian fur auctions it was not put up for sale.