An animal that does not shed seasonally. Spring and autumn molt of wild animals

Wool is an indicator of a dog's well-being. Thick and shiny - indicates excellent health, dull and thinning - signals a malfunction in the pet's body.

"Planned" molting

All dog breeders are ready for it, observing the seasonal change of undercoat and coat in spring / autumn. This is a natural process that takes 1-2 weeks in short-haired dogs (with regular combing) and a little more in animals with a thick undercoat and long hair.

It is interesting! The first molt begins at different times, but, as a rule, it is associated with the time of year and appears no earlier than the quadruped is 6 months old.

Seasonal molting is a predictable event, the consequences of which are easy to deal with: you need to comb your dog more often, if necessary, visit the dog hairdresser and clean up the apartment every day.

"Unscheduled" molting

If the wool began to fall out in frightening quantities, and it’s not spring or autumn outside, head to the veterinarian. He will make a qualified diagnosis and determine the treatment algorithm.

The most common causes of out-of-season molting are:

Look for insects and signs of their presence, which can be redness, swelling, bite marks (dots), black grains and scratches. A dark coating in the auricles may suggest that an ear mite has settled there. Clean your ears and apply mites.

Important! Also check the dog mat, and if you suspect something is wrong, change it to a new one.

Skin diseases

You can run into eczema by washing your furry dog ​​around and around. A dense, wet undercoat that does not have time to recover will easily provoke this serious disease, which will give impetus to an out-of-season molt.

The cause of dermatitis and similar ailments leading to severe hair loss can be low-quality dog ​​cosmetics (shampoo and conditioners).

A good owner is obliged to be alert when he feels an unusual smell from the pet, which will tell about violations in the activity of the skin glands.

Allergy

It is usually supplemented by concomitant symptoms: anxiety, redness of the eyes, itching, discharge from the nose and eyes, rarely salivation.

Do quite healthy dog maybe suddenly as if on unfamiliar food, and on any provoking factor, including plant pollen, poplar fluff and dirty air.

If you recently gave your dog some new item (bowl, clothes, rug), replace them with others and look at the reaction of the animal.

Stress

Unexplained hair loss is often associated with psychological discomfort. A dog's feelings can be caused by anything - your anger, a street dog fight, a move, pregnancy, participation in an exhibition, an injury, an operation, or another stressful event.

Shedding on nerves does not differ in intensity and passes in three days.

Malnutrition

It is it that is quite capable of acting as a catalyst for unexpected hair loss. Elite factory feeds are beyond suspicion, but economy-class dry foods are the main enemies of healthy dog ​​fur.

In cheap drying, there is a lot of salt and no vitamins, which are necessarily added to high-quality products. And if the pet is prone to allergies, look for packages with the inscription or “holistic”.

Skin and coat need vitamin nourishment from the inside.

Important! If your dog eats only natural foods, mix vitamin and mineral supplements into his meals from time to time.

Hair care

You can’t do without it both with seasonal and with a sudden molt. Get something that will help you maintain a healthy coat:

• protein shampoo;
• dry conditioners (improving the structure of the hairs and nourishing them);
• Nickel-plated combs to remove tangles;
• slicker brushes for delicate hair removal;
• a brush-glove that easily collects hairs;
• a furminator that can replace the entire arsenal of dog combs.

If you make it a rule to comb out the hair that falls out every day, it will not fly all over the apartment, clinging to the owner's clothes and settling on furniture.

The combing procedure will become less laborious if the preparatory stage is observed: before proceeding with it, cover the floor with newspaper or polyethylene.

Menu when shedding

It should be special, preferably with an emphasis on natural food with a large dose of proteins.. It is protein that is responsible for a healthy and beautiful dog coat.

• meat, with the exception of pork;
• chicken liver and hearts;
• sea ​​fish (without bones);
• boiled and raw vegetables;
• porridge.

Important! And by all means, put some fish oil in your dog's food, as well as supplements with vitamin B, copper and zinc, which stimulate hair growth.

Hair loss fight

It is carried out if the molt is not burdened by side symptoms - poor appetite, nervous behavior, high body temperature and others.

Put your pet on a diet or change food without ignoring vitamin and mineral complexes.

Measure the humidity and air temperature in the house: at + 25 ° and above, molting can be considered a natural phenomenon. Negative factors include low humidity (less than 40%). The way out is to regulate the temperature with the help of thermostats, systematically ventilate the apartment, install an air humidifier.

Walk more often, taking your pet into the yard 2-3 times a day, regardless of the weather. Moderate cooling can stop the molt. But do not overdo it so that the dog does not catch a cold.

And ... save your dog's nerves. As you know, all diseases occur on a nervous basis, and untimely molting is no exception.

Moult

The change of coat and skin changes closely related to it are a very delicate biological process that initially ensures the preservation of the integrity of the body integument, as the main protective formation of mammals. Guard, guiding, and partly downy hairs, elastic hair brushes on the soles of the feet, and other relatively delicate formations that often come into contact with the substrate and surrounding objects wear out quickly. Premature severe wear of the fur occurs in the corsac fox ( Vulpes corsac), hiding for the day in dense reed beds, in sable ( Martes zibellina), often hiding in narrow passages between stones, at a mole digging the ground ( Talpa europaea), etc. In the process of molting, these defects are eliminated.

While in amphibians and reptiles - animals with a variable body temperature, the change of covers simultaneously covers all its parts, in warm-blooded animals - birds and mammals, during molting, as a rule, the covers of individual parts of the body are successively replaced. This feature is associated with the complication of the structure and functions of the covers.

The development of a new fur begins with the laying of guard hairs, from the bags of which, it is believed, the rudiments of downy buds are already budding. The process of hair replacement in different groups of mammals proceeds differently. In predatory animals, the germ of a new hair is laid from the cells of the bottom of the old bulb. As you grow new hair pushes out the old one separated from the bulb, but for quite a long time kept in the hair bag. In rodents, the laying of the rudiments of new hair occurs completely independently of the old hair bags that fall out. Therefore, in contrast to the predatory ones, the groupings of the hairs of the new fur do not correspond to those of the old one.

Drawing of a molt on the mezdra of a steppe mouse ( Sicista subtilis). Due to the different intensity of pigmentation of the new hair follicles, the location and width of the dark and light stripes on the back of the animal are accurately reflected. (According to Barabash-Nikiforov and Formozov, 1963.) Pigment grains are concentrated in the rudiments of new hair. Translucent through the subcutaneous tissue, they give a bluish color to the mezdra (the lower surface of the skin). Since molting in different parts usually does not occur simultaneously, but in a certain sequence, a characteristic pattern is formed on the mezdra - a molting pattern, consisting of the so-called. moult spots. By their location and shape, one can judge the onset of one or another stage of molting. With the growth of hair, which removes the pigment from the skin, the mezdra becomes lighter, proceeding in the same sequence as its darkening. The core completely cleared of spots is a sign of the end of the molting process. Naturally, with the development of white (non-pigmented) hair, molting spots on the core are not formed.

Successive stages of color change of the mezra during the autumn molt common squirrel (Sciurus vulgaris) (according to Barabash-Nikiforov and Formozov, 1963). Molting is often associated with a change in the structure of the fur and its color, sometimes expressed very sharply. Other structures are also subject to change. So, during the molt, the dermis is loosened by the developing rudiments of new hair and, accordingly, thickens; in the interline periods, it is compacted. The fat layer, strongly developed in winter, thins out or completely disappears by summer. During the molting period, the need for mineral nutrition and vitamins also increases, protein metabolism increases, excitability increases. Thus, the entire body of the animal is involved in the physiological process associated with molting.

It has been established that the mechanism of molting is based on the hormonal effects of the pituitary and thyroid glands. The pituitary gland acts on thyroid gland, and its hormone thyroidin causes molting of integuments of a protective and thermally insulating type. But these processes are not autonomous; they are controlled and influenced by the external environment.

The main factor influencing seasonal molting is temperature. However, the start of this process is stimulated by a change in the duration and intensity of illumination, which acts through visual perception on the pituitary gland. At the white hare ( Lepus timidus), for example, molting is primarily dependent on photoperiodism, and temperature serves as a factor accelerating or delaying hair change. Under experimental conditions, by reducing or lengthening the duration of illumination, it is possible to change the timing of molting, greatly accelerate the maturation of the fur, which has a significant effect on fur species. economic importance. So, shortening the duration daylight hours in summer, i.e., during the period of the longest natural daylight hours, it is possible to accelerate the maturation of mink winter fur by more than a month ( Mustela lutreola) and foxes ( Vulpes vulpes ).
In mammals living in conditions of a pronounced change of warm and cold seasons, there is a periodic more or less complete change of coat. This is necessary mainly because the same type of cover with a certain thermal insulation capacity cannot be suitable throughout the year. For example, in a number of arctic animals with well-developed physical thermoregulation in winter, maintaining a constant temperature level in the most severe frosts is ensured by the high thermal insulation properties of the fur. In summer, the constancy of their body temperature is achieved to a large extent due to an increase in the thermal conductivity of the cover by 3-4 times compared to winter, and also due to the well-developed mechanism of thermal shortness of breath and heat transfer through the limbs.

Most of the animals inhabiting the northern and temperate zone (hare ( Lepus timidus), foxes ( Vulpes vulpes), arctic fox ( Vulpes lagopus), etc.) during the year there are two molts - spring, in which thick high winter fur is replaced by rare and low summer fur, and autumn, when the reverse process occurs. Before the start of the spring molt, the fur fades, the hair loses its elasticity, the awn breaks, downy hair often becomes felted. Next, the development of new and loss of old hair begins. The spring molt may be more or less incomplete. At the mole ( Talpa europaea), for example, patches of winter fur often remain after the spring molt. Mink ( Mustela lutreola) in the spring molt loses downy hair, while the outer hair falls out only during the autumn. The autumn molt differs from the spring molt by a large stretch of time and a complete change of hair. The spring molt usually starts from the head and back, spreading from here backwards to the sides and abdomen; autumn molting proceeds in the reverse order. Particularly rapidly, in a certain short time, seasonal molting occurs in the inhabitants of areas with a sharply continental climate.

Often, changing from one seasonal outfit to another completely transforms the appearance of the animal. Summer sable fur ( Martes zibellina) dark, short, tight to the body. In this outfit, the animal looks lean, skinny, big-eared and rather long-legged. After the autumn molt, the ears are almost completely hidden in high shiny and thick fur, the tail dressed with long hair becomes magnificent, and the legs seem shorter and thicker. In winter, the sable is a stocky, strongly built animal. The appearance of foxes dressed in summer and winter fur changes even more strikingly ( Vulpes lagopus), white hare ( Lepus timidus), some subspecies of the squirrel ( Sciurus vulgaris), saiga ( Saiga tatarica), bison ( bison bison). At the Bactrian camel ( camelus bactrianus) grows a long wavy coat for the winter, and in the summer it is almost naked. In spring, the shedding winter coat hangs from its body in tufts.

Moulting reindeer (Rangifer tarandus). It has been suggested that the white hare ( Lepus timidus), ermine ( Mustela erminea) and fox ( Vulpes lagopus) summer fur does not fall out during the autumn molt, but remains for the whole winter, growing and depigmenting. However, it turned out that the winter attire consists entirely of newly developed hair, which has a different size and shape than the summer ones. The density of hair and the ratio of their categories in summer and winter fur are also not the same. So, for a squirrel ( Sciurus vulgaris) per 1 sq. cm of a rump in summer there are an average of 4200 hairs, in winter - 8100, the same for a white hare ( Lepus timidus) - 8000 and 14700. The length of the hair in millimeters on the rump is as follows: for a squirrel in summer: fluff - 9.4, awn - 17.4, in winter: 16.8 and 25.9; the same for the white hare: in summer: down - 12.3, awn - 26.4, in winter: 21.0 and 33.4. At the hare-hare ( Lepus europaeus) per 1 sq. cm in summer, the average number of guard hairs is 382, ​​intermediate - 504, down - 8156 with an average length of the last 18.5 mm. In winter, the same series of numbers looks like this: 968, 1250 and 18012, the average length of the underfur hair is 22.2 mm. Only 1 sq. cm in summer there are 9042 hairs, and in winter 20240. Thus, the density of the coat more than doubles, which occurs mainly due to a sharp increase in the number of downy hairs.

No less sharp are the seasonal changes in the fur of the Central Asian earthen squirrel living in the deserts ( Spermophilopsis leptodactylus). This animal does not hibernate for the winter and is thus active both in summer, when the sand heats up to 60-80 ° C, and in winter, when there is enough severe frosts. His summer hair is more like short, flat needles that fit snugly against his body. On the back, the number of guard and guide hairs per 0.25 sq. cm - 217, intermediate and downy - 258, total - 475 with a length of 1 to 7.5-8.5 mm. The same in winter: outer, guide, intermediate - 132, down - 1109, total - 1241. The length of winter hair reaches from 9.2 mm to 18.1-20.9 mm; they are soft and silky. The delicate winter fur of the ground squirrel is very different from the hard and coarse summer fur. Such a pronounced seasonal fur dimorphism in this species is consistent with the large annual temperature range of the sandy desert.
Terms of molting of small insectivores and rodents of Karelia (according to Ivanter et al., 1985):

a - spring, b - juvenile, c - autumn, d - compensatory, e - summer. In mammals hibernating (most ground squirrels ( Spermophilus), marmots ( Marmota), etc.), and seals also molt once a year, in spring and summer. On the other hand, in excavations of the temperate zone, the hairline of which, due to constant friction in the narrow passages of burrows, wears out especially quickly in some places, in addition to the two usual molts, a third one is observed - restorative, or compensatory. Unlike ordinary molting, it affects only areas of the fur that are subject to intense wear. Such a restorative molt can be traced in moles (T alpa), mole rats ( Spalax) and mole voles ( Ellobius). Basically, it is confined to the summer period, but partially (in moles) is also observed in winter. Earthmovers living in warm regions, cost only compensatory molting.

In mammals that do not experience a sharp change in seasonal conditions (inhabitants of tropical countries, semi-aquatic forms), there are no seasonal differences in the hairline or they are insignificant, molting proceeds imperceptibly, often in the form of a loss of old hair and the appearance of new hair extended throughout the year.

The duration of the only molt in the year and the wearing of a changed outfit in adult harp seals ( Pagophilus groenlandicus) of the White Sea herd (according to Barabash-Nikiforov and Formozov, 1963). Yes, muskrat Ondatra zibethicus) is characterized by a very frequent and long stay in the water when searching for food, building huts, settling, and pursuing competitors. Since the water temperature in all seasons is much lower than the body temperature of the animal, the weakening of the protective role of the hairline could cause adverse consequences for it. As a result, the ratio of the number of hairs different categories(guides, outer, intermediate and down), per unit area of ​​muskrat skin, is almost the same throughout the year and does not depend on seasons. The molt of adults lasts almost all year round. Only during a short period of time (in April or May in muskrats of the northern half of the European part of Russia and neighboring countries) at the end of winter, the skins do not have traces of molting. But already in May, the mezdra begins to thicken, and then a blue appears on it - accumulations of pigment in the bulbs that form a new hair shine through. The stretched, slow molting course determines the good condition of the muskrat fur in all months of the year. Only on the dorsal side of the body, which less often comes into contact with water, the density of the fur changes somewhat with the seasons: in July it is about half as much as at the end of winter. Since August, the density of fur increases again. Young muskrats of early broods during the autumn-summer period have two age molts, and animals from late broods have one, which, moreover, passes more quickly. A slow, extended molt is also characteristic of the muskrat ( Desmana moschata), sea otter ( Enhydra lutris), otters ( lutra lutra ) and, to a lesser extent, mink ( Mustela lutreola).

Seasonal color changes, which often occur when the coat changes, have a masking function. This is especially pronounced in species that turn completely white for the winter. The average duration of wearing winter white fur, which harmonizes well with the background of the snow-covered ground, corresponds quite accurately to the average duration of permanent snow cover in a given area.

Ermine ( Mustela erminea) in the northern strip of the European part of Russia for about 8 months a year wears white winter fur of the month and only about 4 months - reddish-brown (matching the color of the soil) summer; in the southern zone - only 5.5 months in winter and about 6.5 months - in summer. The change of fur cover in the latter case is as follows. In March or April, first on the back, and then on the sides of the ermine, dark hairs appear; this continues until all top part the skin will not become reddish-brown. The belly remains white. In October, with the shortening of the day, a new molt begins: dark hairs are replaced by white ones, first on the sides, and then on the back, which makes the animal appear spotty. By November, he is already completely winter-white, with the exception of the black tip of the tail. Moulting and those animals that live in a warm climate. In autumn they grow new wool, but not white, but the same brown as in summer.

Seasonal changes in hair color in ermine ( Mustela erminea) (after Carrington, 1974). Weasel living in the north of Eurasia ( Mustela nivalis) for the winter also turns white. In areas with a short or little snowy winter as warm (the south of Western Europe, the south of Ukraine, Transcaucasia, many areas Central Asia), and frosty (Mongolia) winter weasel fur becomes thicker than summer, but, with rare exceptions, retains its brown or reddish-gray color. Under the conditions of Central Europe, summer coloration, as a rule, remains, but if it does change, it does not change much, and large or small white spots appear.

On the Kola Peninsula, near the Arctic Circle, the white hare ( Lepus timidus) can be seen in white fur from about October 20 to May 20; stable snow cover in the forest lies on average from October 31 to May 21 (from October 4 to October 31 there are frequent snowfalls, but the cover is unstable - it disappears at times, reappears, etc.). In Russia, the timing of the spring molt of the hare roughly coincides with the period of intense snowmelt and snowmelt, and the autumn - with "pre-winter" - the time of cold rains, followed by more and more frequent snowfalls. Greenland hare ( Lepus arcticus groenlandicus) most of the year wears winter white fur, and his summer is not brown, but almost white, only slightly smoky on his back. On the other hand, the geographic races of the whites that penetrated into North America along the mountain ranges to the south, to the snowless regions of the USA, they do not turn white for the winter. From European forms, Scottish hare ( Lepus timidus scoticus) is brownish-gray in summer, pure white in winter, but with low and not lush fur, and Irish hare ( Lepus timidus hibernicus) becomes noticeably grayer in autumn; only a few individuals become white.

white hare ( Lepus timidus) in summer attire. Chamois darken by winter ( Rupicapra rupicapra) and individual deer. So, Manchu ( Cervus nippon mantchuricus) and Japanese ( Cervus nippon nippon) spotted deer in summer they are equally covered with white spots. In winter, spots remain only on the Manchurian form, while the Japanese form, which lives in deciduous forests, acquires a monotonous brown color.

Although the course of molting is closely related to external conditions, yet such a complex process cannot always and very accurately follow all the vagaries of the weather. Indeed, there are years when the snow cover is established later than usual and the white winter attire of weasel, ermine, hare is very noticeable against the dark background of the earth covered with dead grass and fallen leaves. Belyaks at such a time are looking for more reliable shelters for daytime rest: they lie down under the protection of the lower branches of fir trees, under the tops of trees that have fallen to the ground, or in a swamp on hummocks overgrown with thick sedge. Weasel spends most of the time in the burrows of voles, moles and appears on the surface of the earth relatively rarely and for a short time.

At early spring and accelerated snowmelt, the listed animals are sometimes “late” to change their winter outfit for summer and for two weeks, and sometimes more, they live with the absence of a camouflaging fur color unfavorable for them. The white hare, being more conspicuous and having many enemies, reacts more strongly than weasels and ermines to such a combination of circumstances. It comes out to feed only in the dark, during the day it often hides on the last drifts of snow, where it is very difficult to notice it. Of course, in such years, animal populations for some time suffer greater than usual losses from predator attacks. However, on average over a large number of years, the significance of the advantages in the struggle for existence, which the seasonal change of protective colors gives to the species possessing them, is beyond doubt.

white hare ( Lepus timidus) in winter attire. The influence of the external environment on the timing of molting and on the nature of the seasonal dimorphism of the hairline is proved by the practice of acclimatization of mammals. For example, in species exported from countries northern hemisphere and released in Australia, New Zealand and South America, the timing of molting, as well as hibernation and reproduction, gradually shifted. Animals released into regions with relatively harsher conditions than in their homeland acquired more lush winter fur (for example, a raccoon dog ( Nyctereutes procyonoides) in a number of areas former USSR). On the contrary, acclimatized species that have fallen into the conditions of a relatively warm climate (teleut squirrel ( Sciurus vulgaris exalbidus) in the Crimea and the Altai squirrel ( Sciurus vulgaris altaicus) in the Caucasus), have lost their characteristic delicate and high fur: it has become coarser and shorter. It is interesting that white hares, caught in Norway and released in the middle of the 19th century in the Faroe Islands, still wore a white winter outfit in the first period of acclimatization, and now they wear reddish-brown fur similar to summer in the cold half of the year. In conditions of snowless winters, a white outfit is unprofitable because it is too noticeable; the island population lost this useless and, perhaps, even harmful feature of the seasonal outfit in about a century.

In addition to strengthening the heat-insulating and maintaining the relevance of masking properties, the hairline in many species during the autumn molt acquires a number of features that are necessary and beneficial precisely in winter conditions. For example, the structure of the cuticle of the outer and guide hairs of winter wolverine fur ( gulo gulo) is such that even in the most severe frosts frost does not sit on them. This is also characteristic of the guard hairs of the tail of the fox ( Vulpes vulpes) and fox ( Vulpes lagopus). Both of the latter species, when resting in the snow, curl up and cover their heads with their tails (the muzzle is covered with relatively very short fur and, naturally, should suffer more from the cold). If frost, formed from breathing, settled on the tail hairs, these animals would inevitably freeze head to tail and, upon awakening, would damage the coat.

Stages of molting red deer (Cervus elaphus) (according to Geran, 1985):
A - in autumn; B - in the spring. Lynx foot soles ( lynx lynx), wolverines ( gulo gulo), arctic fox ( Vulpes lagopus), northern races of foxes ( Vulpes), martens ( Martes), protein ( Sciurus) and some other species by the end of autumn are densely overgrown with rather long elastic hair, almost completely hiding the areas bare in summer. The resulting thick hair brushes not only insulate, but also protect the fingers and feet from possible damage when digging out the old snow, dense crust, etc. At the same time, these brushes increase the supporting surface of the paws, creating a semblance of skis or snowshoes, which makes it easier for animals movement on loose deep snow. The significance of such dense pubescence of paws in the life of the wolverine is especially significant ( gulo gulo), sable ( Martes zibellina), pine marten ( martes martes), whose diurnal transitions in winter, during the period of snow, are very large. Brush hair is shed during heavy snowmelt in the spring, as soon as it becomes unnecessary. It is significant that the subspecies of foxes inhabiting the steppes and deserts with a frosty but little snowy winter lack these brushes; little pubescent for the winter and the feet of the paws of the southern subspecies of the European hare ( Lepus europaeus), as well as a tolai hare ( Lepus tolai). On the contrary, among the Russians, occupying northern part range, the feet for the winter are overgrown with a brush, almost as thick and long as that of the white hare, better than other Palearctic hares adapted to life in snowy areas.

At the squirrel ( Sciurus vulgaris) when changing from summer to winter fur, quite long and thick hair tassels grow, covering the distal, most chilling edge of the ear. They reach full growth by the end of the autumn molt, and hunters in the first days of fishing often determine by the length of the tassels whether it is worth shooting this or that squirrel hiding on the top of a tree. The hair of the tassels falls out rather quickly in the spring, but some survivors disappear only in June - July. In summer attire, the ears of an adult squirrel are covered with very short hair. Tail hairs change very slowly. It performs a number of functions in a squirrel and, in particular, during large jumps from tree to tree, it supports the animal in the air, facilitating planning. He plays this role throughout the year, regardless of the season. The stormy spring molt of the squirrel's fur, starting from the head, reaching the base of the tail in early May, slows down sharply. In an adult animal that has received a summer outfit, worn and burnt winter tail hairs completely fall out and are replaced by new ones, also winter ones, only by September. Due to the gradual shedding in all months of the year, the tail, dressed in long hair, can be used as a parachute; he molts once a year, while the head, body, legs - twice. The functions of the hairline of different parts of the body are not equivalent, in connection with this, molting does not follow one pattern, but several.

Successive molting stages of the common squirrel ( Sciurus vulgaris) (according to Barabash-Nikiforov and Formozov, 1963):
A - spring; B - autumn. In addition to seasonal changes in hairline, there is also an age molt, in which the juvenile attire (attire) is replaced by the definitive adult. In some species, the latter appears after several age molts (for example, in a rabbit ( Oryctolagus cuniculus) there are up to 4 of them). Age molting in a number of true seals (Phocidae) is associated with a change in the uterine attire of a white seal (white high fur with outer and thick downy hair, unsuitable for diving, lasts for about 20 days in pups) for a serka outfit of coarse short hair (the serka is already catching food in sea). With subsequent annual molts, which are both seasonal and age-related, the color of the animal in 2-3 years approaches that characteristic of mature individuals.

In rodents that bring several broods per year, young at the first juvenile molt receive different outfits depending on the season. For example, young squirrels ( Sciurus vulgaris), born in the summer, receive a summer adult outfit, and those who appeared at the end of winter, not yet reaching full growth, receive lush winter fur and thick tassels on their ears. Young ungulate lemmings ( Dicrostonyx torquatus), born in snowy nests, at the first molt get a thick white outfit, similar to winter adult lemmings. Since the timing of molting varies depending on sex and age, as well as the physiological state of animals, feed and weather conditions, it is quite difficult to accurately determine the state of the fur cover of a particular population of mammals. Moles ( Talpa europaea), for example, males molt much later than females, in dwarf bats ( Pipistrellus pipistrellus), on the contrary, males begin to molt. Well-fed animals of various species molt earlier than emaciated ones. In pregnant females and sick individuals, molting is delayed for a long time at any stage; A strong infection with helminths also has a noticeable effect on the course of molting.

In addition to hair, molting is characteristic of almost all horny formations of mammals: periodically there is a change of claws, desquamation of keratinized cells of the surface layer of the epidermis, annual shedding of antlers in most deer (Cervidae), etc. patches is characteristic of northern seals - lysuna ( Pagophilus groenlandicus), ringed seal ( Pusa hispida), sea hare ( Erignathus barbatus). These pinnipeds lie on the ice or shore during the molting period and do not feed for a long time. From land mammals the same intense molting is observed in the Trans-Baikal tarbagan marmot ( Marmota sibirica) and selevinia ( Selevinia betpakdalaensis). On the other hand, derivatives of the skin, which have pronounced defensive functions, are replaced slowly and gradually. For example, the quills of porcupines (Hystricidae) and urchins (Erinaceidae) fall out in just a few pieces per day. At the eared hedgehog ( Hemiechinus auritus) 5-20 needles fall out per day, thanks to which the animal keeps its prickly shell suitable for defense all the time. One at a time, tactile hairs (vibrissae), hard bristles on the rims on the paws of semi-aquatic animals fall out and are replaced.

Forepaw of the ungulate lemming ( Dicrostonyx torquatus). The claws of the III and IV fingers are large and forked in winter, as not only the claw itself grows, but also the keratinizing pad of the fingers. In spring, most of the forked claw falls off - it acquires its usual size and a sharp end. (According to Barabash-Nikiforov and Formozov, 1963.)

Winter has passed, and with it the snow and cold. The long-awaited spring has come, the sun is baking - the best time to go to the zoo. But some visitors are unhappy and complain: why are snow goats so shaggy, and their hair sticks out in tatters, why does the fox's fur lose its winter shine and look somehow dull? Even usually neat wolves look somehow unkempt.
In fact, everything is very simple: our animals molt. In the spring, they no longer need a long, thick and lush hairline, without which they could not survive. harsh winter. It's time to replace it with another, lighter, summer one, which is half as long and less frequent. For example, a squirrel per 1 square. cm of the surface of the body, instead of 8100 winter hairs, only 4200 summer hairs grow, and in a hare, instead of 14 thousand hairs, only 7 thousand.
Animal molting has long been of interest to zoologists. Research recent years It has been established that, in addition to temperature, it is affected by light acting on the animal's body through the endocrine gland - the pituitary gland. For molting a hare, the length of daylight hours is a determining factor, while temperature only accelerates or delays this process.
The timing of molting in wild animals depends on the geographical latitude of the area. In some mammals and birds, along with molting, the color also changes: light is replaced by a darker one. The white winter color of the white hare turns gray in summer, and the squirrel turns from gray in spring to red. A similar transformation occurs with the stoat, ptarmigan, and other species. Here, too, everything is clear, in winter the animals become invisible against the background of snow, in summer it is more difficult to notice them against the background of earth and grass. This is called protective coloration.
The molting of animals takes place in strict sequence and in each species in its own way. For example, in a squirrel, spring molting begins with the head. First of all, bright red summer hair breaks through at the front end of her muzzle, around her eyes, then on her front and hind legs, and lastly on her sides and back. The whole process of "dressing up" lasts 50-60 days. In the fox, signs of spring molting appear in March. Her coat loses its luster and begins to thin out gradually. The first signs of molting can be seen on the shoulders, then on the sides, and the back of the fox's body remains covered with winter fur until July.
Almost all animals shed. But the inhabitants continental climate, characterized by sharp seasonal changes in temperature, change cold winter and hot summers, they shed quickly, but the inhabitants of the tropics and semi-aquatic animals (giraffe, muskrat, nutria, sea otter) - gradually. Most mammals living in temperate latitudes molt twice a year - in spring and autumn, but some animals (seals, marmots, ground squirrels, jerboas) - once.
Shedding is a natural process in which old and dead cells and tissues are replaced by newer ones. So, the fact that our animals shed is an indicator of their health. But if the shedding becomes irregular and is accompanied by various painful phenomena (as it sometimes happens in domestic cats and dogs), this can really be a cause for concern.
Now comes the turn of the second question: why do we not comb out our molting animals? Well, firstly, this is not entirely true: we still help pets to get rid of winter wool. For example, a yak living in the Children's Zoo is regularly combed out. But only with predators it will not work out - after all, the zoo is not a circus, here not all animals are allowed to touch themselves. But they, too, are not "left to the mercy of fate." Take a closer look: in some enclosures (for example, in musk oxen) you will notice old Christmas trees or special structures made of different materials- the so-called "chesalki". Animals itch about them regularly and with obvious pleasure. And their winter wool does not go to waste - its employees then collect and give it to birds and small animals, which use it to build nests. Such nests can be seen in the "Night World".
Well, in conclusion, let's see who actively molts in the zoo in spring, who should be turned to Special attention who are interesting to watch. Molting is easy to spot in guancos, domestic llamas and vicuñas, foxes and hares, gray and red wolves, raccoons and raccoon dogs, musk oxen, snow goats and camels. Maybe you yourself will add someone to this long list?
M.Tarkhanova

Molting, i.e., the seasonal change of fur and associated changes in the skin of mammals, is the most important biological process designed to ensure the integrity of the body integument as the main protective and heat-insulating formation.

For small insectivores and rodents that spend a lot of time in the litter and burrows and are constantly in contact with a solid substrate, regular molting is of particular importance, since their hairline wears out quickly and requires timely replacement. The need for a periodic change of fur is also dictated by seasonal climate changes, being a means of increasing heat transfer in summer and decreasing it in winter. As our studies have shown, the timing and intensity of molting vary depending on sex and age, as well as on the physiological state of the animals, food and weather conditions. Therefore, specific features of the course and rate of molting in animals of different age and sex groups can serve as a kind of indicator of the state of the entire population and signal serious violations of important ecological, physiological and population processes.

Most authors, discussing the course of spring molting in shrews, describe waves of long and short hair following each other in a special order on different parts of the body of the animal, but do not report anything about the darkening of the core. Meanwhile, when considering the autumn molt, they specifically emphasize this phenomenon. All of them are unanimous in the opinion that the autumn molt begins in the sacral region and continues towards the head, gradually moving to the ventral side. Spring molt, on the contrary, begins with the head and spreads to the sides to the tail and belly. Nevertheless, other authors argue that the spring molt of the common shrew takes place in reverse order: starts on the ventral side of the body and ends on the dorsal side.

The fact that no characteristic changes in the skin (pigmentation of the mezra) were noticed in spring led to the birth of the hypothesis that shrews do not have a normal spring molt (new hair growth), but the so-called “reduction” occurs - breaking off the last segments of winter hair along constrictions and the transition of part of the guard hairs to downy ones. This hypothesis was criticized by later researchers, who had specimens in their collections in the stage of normal spring molting with dark spots on the mezra and the growth of a new hair. Cases when the animal had both a short and long hair on the different parts skins (for example, long on the abdomen and short on the back) with a sharp border between them, but without pigmentation on the inside, they considered as a break in molting. Later, abandoning the “reduction” hypothesis, Borovsky also came to this. According to his new ideas, waves of short and long hair pass through the animal's body twice: once from the ventral side to the dorsal side and shortly after that in the opposite direction - from the back to the abdomen. In the light of these data, it is not difficult to reconcile the statements mentioned above regarding the direction of the spring molt. V. A. Popov and Scaren observed the first phase of the spring molt, and Denel, Crowcroft and other authors observed the second phase.

In the detailed work of Borovsky, which was then confirmed in the studies of a number of zoologists, it was shown that shrews in the spring have two successive molts, different in nature, timing and direction in which they proceed. Spring molt I (VL-I) consists in the change of a six-segment winter hair to a five-segment spring one and passes from the ventral side to the back. During spring molt II (VL-II), this five-segment spring hair is replaced by a four-segment summer hair. It starts on the back and ends on the abdomen. The molt can capture most or all of the animal's skin ("full" molt, in Borovsky's terminology) or pass within a narrow (1-5 mm wide), gradually moving strip on the skin ("wave" molt). In addition, intervals (breaks) in molting are often observed, and then the shrew can simultaneously have long hair on one part of the body and short hair on the other without skin pigmentation. Such an "interrupted" molt is observed during VL-I in 40% of individuals, VL-II - in 22%.

Regarding the autumn molting of shrews, the opinions of various researchers are generally quite close. All of them agree that it passes in narrower terms than in spring, begins on the back, near the base of the tail, spreads forward to the head, and then passes to the abdomen. They are less unanimous on the issue of the so-called "intermediate" molt. For example, Stein believes that a small part of the shrew population, in addition to the normal spring and autumn molts, goes through three more: one - in their first summer, the other - in the second and last (third intermediate) - shortly before death, in the fall ("senile molting" ). With regard to wintering individuals, the existence of senile molting, which lasts from May to November, was confirmed by Borovsky's studies. At the same time, Crowcroft believes that the "intermediate" summer molt is a delayed spring or early autumn. Scaren agrees with this.

According to Borovsky’s many years of research, representatives of the genera Sorex and Neomys have four molts during their life: autumn, two spring and senile, and the juvenile molt is also observed in the water shrew. At different types shrews, these molts proceed synchronously in time and direction: autumn - from the head to the abdomen, spring - first from the abdomen to the back, and then from the back of the back to the abdomen, senile - diffusely, juvenile - from the ventral side to the back. It differs in timing only VL-II; in the water shrew it passes later than in shrews.

Based on our data presented in the relevant sections of the first chapter, we can conclude that there are no significant species differences in the timing, intensity, and course of seasonal molts. Meanwhile, the connection with sex, age and the state of the reproductive system appears quite clearly. It has been established, for example, that the spring molt in breeding females begins somewhat earlier than in males and females not participating in reproduction. The autumn molting of the newly arrived animals in all species of Soricidae occurs in close terms (September-October) and consists in the change of short summer hair to longer and thicker ones. The appearance of a new fur is preceded by morpho-forming processes in the skin (loosening, thickening, pigmentation). They usually begin on the back at the rump, then spread forward to the head, then move to the sides and end on the abdomen.

In spring, in April-May, adult (overwintered) individuals molt. The hair change begins on the ventral side of the body with a gradual coverage of the sides, and ends on the back or head. The two-stage nature of the spring molt with the opposite direction of fur change (in some animals it goes from belly to back, and in others - from back to belly) we, unlike Borovsky, explain not by the existence of two spring molts, but by the non-simultaneous entry into molting of representatives of different age generations. The individuals of last year's spring litters, i.e., older in age, begin to molt first. They form imaginary VL-I with a characteristic ventrodorsal direction of the process. As for the second stage of the spring molt (according to Borovsky, this is VL-II), it corresponds to the mass molt of animals of late (summer) generations and has a dorsoventral order of fur change. The real autumn molt in these animals, apparently, is generally absent. Instead, they have an senile molt, which, as a rule, affects only certain areas and does not have a clear pattern. The conclusion suggests itself that any seasonal molt - whether it be spring or autumn - if it is the first in the life of an animal, begins on the dorsal side of the body, and if the second - on the ventral. Finnish researchers also come to the denial of two spring molts. Thus, under the conditions of the North, shrews undergo two normal seasonal molts (spring and autumn), as well as senile. The shrew, in addition, has a juvenile molt, and the mole has a compensatory one.

The molting of rodents, especially commercial and semi-commercial, is the subject of a comparatively large literature. There are works on mouse-like rodents - representatives of the genera Clethrionomys, Microtus, Lemmus, Arvicola, Micromys, Apodemus. However, the most detailed studies on seasonal changes in the fur of small rodents were carried out by Lehmann, AI Kryltsov, and Ling.

Based on the study of mass species of rodents in Kazakhstan, A.I. Kryltsov comes to the conclusion about the exceptional stability and uniformity in the sequence of hair change in all voles of the Old World, which almost does not depend on the way of life of animals. In the inhabitants of swampy meadows and forests - field voles and root voles, in typical semi-desert forms - social voles, in semi-aquatic forms - water rats and muskrats, even in such specialized underground rodents as mole voles, one and the same course characteristic of most of the studied species is observed. fur change. It occurs according to the sublateral (dorsal) type, in which new hair appears first on the lower parts of the sides and head, then the process spreads to the abdomen and back, and lastly the top of the head and back of the back are shed. In general terms, the sublateral type of hair growth is preserved in all types of age and seasonal molts, only the sequence and speed of shedding of the head, middle and back of the back varies. Only in some representatives of the genus Clethrionomys, as well as in the Norwegian lemming, all or part of the individuals of the species during one of the seasonal molts change their fur according to the cephalo-sacral type. The order of hair change in this case is reverse to that described: it begins with two oval spots on the back of the back, then goes to the head and ends on the sides and abdomen. Old animals in all species have a diffuse type of molting, in which no regular sequence is observed in its topography.

Our studies generally confirm the conclusions of the authors cited above. The molting of the studied rodents proceeds according to a single plan and approximately at the same time. For voles, the existence of three molts has been established: juvenile, which, depending on the time of birth of the animal, can take place in spring, summer and autumn and ends with the change of children's fur by adults (summer or winter), and two seasonal ones - spring and autumn, accompanied by a complete change of hair, respectively, to summer and winter. The forest mouse, like probably other hibernating mammals, molts throughout the summer period from May to October, while molting, apparently, proceeds diffusely, in any case, a regular order in the change of fur cannot be established. The autumn molt in all rodents is usually more intense than the spring molt, the terms of which are extremely extended due to the heterogeneity of the population in terms of age. The timing and speed of molts also depend on the sex and physiological state of the animals. Thus, the molting of lactating females is late compared to females without signs of reproduction, but begins 2-3 weeks earlier than in males. The juvenile molt of young late broods usually passes faster than early broods, and nevertheless can pass into autumn without interruption. Adjustments to the general course, pace and order of seasonal molting are made climatic conditions years and the state of the population (level of abundance and phase of the population cycle).

Moult- the process of regular change of external covers in animals, which can have a different character. So, in birds and mammals, a change of skin occurs (wool, fur, feathers, etc.), in reptiles, a change in the epidermis (skin), and in insects, during the molting period, entire parts of the body (exoskeleton, wings, etc.) d.).

Moulting in mammals

During the molting period, most mammals undergo a complete or partial change of coat, and the skin noticeably thickens and becomes looser. In addition, molting in mammals is often accompanied by a change in the upper layer of the epidermis.

There are three types of molting in mammals:

• Seasonal. Such molting is associated with the adaptation of animals to seasonal changes in the environment. As a rule, winter fur is always longer and thicker, which allows it to reliably protect animals from hypothermia, and summer fur, which has a high thermal conductivity, is always much shorter and thinner. Seasonal molting always occurs in autumn and spring, however, hibernating representatives of the animal world do not have seasonal molting at all.
• Age. AT this case there is a change of primary and soft teenage fur to more awned and coarse adult fur.
• Compensatory. It is the result of damage to various parts of the body by chemical influences. Most often, such a molt occurs in livestock.

Moulting in reptiles

Reptiles, like mammals, also shed regularly - they also need to change their skin from time to time to get rid of the old one. The rate of skin aging in reptiles is influenced by many factors: food, environment, and temperature with humidity. At the very beginning of the molting process, a new three-layer epidermis begins to form under the old skin, and as soon as it is fully formed, the old skin begins to slowly peel off. In different reptiles, molting occurs differently: for example, in some species of lizards and snakes, molting often covers the entire body (snakes try to get rid of old skin by rubbing against various objects - stones, etc.), while in other reptiles, molting is similar to peeling and takes a very long time (if snakes are released from the old skin with a "stocking", then many lizards get rid of the old skin in fragments).

Moulting in birds

In birds, molting is accompanied by a renewal of the feather cover - old feathers are gradually rejected by the skin epidermis, and new feathers begin to grow in their place. Moulting also helps birds get rid of worn or broken feathers, which, after some time, are also replaced with new ones. In most species of birds, molting occurs once a year, however, occasionally birds can molt twice a year.

The process of molting in birds looks like this: first, old feathers are shed in one part of the body, and the rudiments of new feathers begin to grow in their place, and as soon as these rudiments turn into full-fledged feathers, the same process is repeated in another part of the body. In a word, this is a cyclical process, accompanied by the symmetrical shedding of old feathers and the growth of new ones. Moulting in birds is a rather exhausting process, since feathers make up from four to twelve percent of the total weight of birds. That is why molting most often begins at the end of the breeding season (when it is still not cold and there is a lot of food). And in some species of birds, males also molt during the mating season - their plumage becomes brighter and more attractive.