Few people have been able to see baby mice, except perhaps those who breed these animals. But breeders claim that success in this fascinating activity is impossible without certain knowledge about the reproduction of rodents. Therefore, we will find out how many times a year a mouse can give birth without harm to health, how many cubs there are in one litter, and what kind of care they need.
What affects the reproduction of mice?
Both in the wild and in the home, several factors influence how mice reproduce. Among them:
- living conditions (temperature, humidity, presence of a permanent nest);
- access to food and adequate nutrition (a hungry female will find it difficult to bear and give birth to healthy offspring);
- health of the female and male.
- Om-Nom-nom
In addition, the weight of the parents also matters. In an emaciated mouse, the pregnancy will most likely end in premature birth or the birth of sick or dead mice. But an obese mouse can also have serious problems conceiving and bearing offspring.
What is the reason for such a large offspring?
One of the reasons why animals in the wild have large litters is due to the environment. Exposure to weather conditions and other factors can lead to high mortality among newborn pups.
Due to the lack of reliable and safe shelter or food, only the strongest survive. Under certain circumstances, females can eat their offspring. According to University of Oklahoma professor Douglas W. Mock, author of books and various publications, mothers can absorb baby mice for two reasons.
- Firstly, the female can leave the strongest ones, since she is not able to feed everyone. This avoids competition for food among those with greater potential.
- The calories gained from eating baby mice allow the mother to provide adequate nutrition for the remaining babies so that they too can produce offspring in the future.
For mice, as for many animals, one of the main instincts is the preservation of the species, and not the survival of a particular individual. And males try to make sure that it is their genes that are passed on to their offspring. If a rodent senses that the pups were born from another male, he can kill them. In this case, females can terminate pregnancy if a new male appears on their territory. In the wild, the lifespan of one individual is about one year, but inside the walls or foundation of your home they can live twice as long. Also worth noting: In the wild, mice's breeding seasons are spring and fall, but indoors they mate all year round! Thus, a pair of rodents has enormous potential for reproduction. One female can give birth to up to sixty mice per year. Remember also that with each litter the number of sama increases, and they are ready to reproduce after just six weeks. Unless you are intentionally breeding mice, this number of pests should come as a shock. Act quickly and get ahead of them.
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>Features of reproduction and birth of mice
Puberty
Puberty in mice occurs quite early. The female's first estrus can begin as early as 5 weeks of age. A female can reproduce fully only after 2-3 months; before this time, the body is still developing and is not ready for the stresses that arise during pregnancy. Therefore, difficulties may arise both with bearing offspring and during childbirth.
The male is ready to mate after his testes descend into the scrotum. This usually occurs between 5 and 7 weeks of age. Under normal conditions and in the presence of sufficient food, the male retains the ability to reproduce almost until the end of his life.
Instinct prevented me from feeding
In the apartment, the mice were transplanted into a small transparent terrarium lined with cotton wool, covered with thick cloth and placed under a table lamp with an ordinary incandescent light bulb, which warmed them gently. In addition, I changed the mouse diet: I bought the “Malyutka” formula from birth and bred it. She continued to feed with a cotton swab.
Very quickly I realized that I couldn’t give them food every two hours, as expected, even if I wanted to: no one had yet canceled work and sleep. Therefore, I set the intervals between feedings at 4-5 hours: nine in the morning, one in the afternoon, five in the evening, nine in the evening, midnight and five in the morning.
Feeding, especially at five in the morning, when I got up on the alarm clock, was fun. It was necessary to dilute a teaspoon of the mixture in warm water, remove the mouse from the terrarium, fix it in your hand, dip a cotton swab in the mixture and let it lick. Instantly, the little mice had an instinct that made it incredibly difficult to feed them. Each one opened his mouth wide, threw back his head and began to shake it from side to side, while simultaneously making a “bicycle” with his tenacious front paws. Most likely, this was how they looked for their mother’s nipple, and with their paws they stimulated her milk production. I had to work really hard to get the cotton wool with the mixture into their mouths. It took 15 minutes to feed each mouse...
Sexual cycle
The sexual cycle in mice lasts on average 5–7 days. This period includes 4 phases:
- precursor (proestrus) - this stage lasts approximately 48–60 hours, during which division of vaginal epithelial cells and keratinization of the upper layer occurs;
- estrus (estrus) – the period lasts 12–18 hours, at this time the upper layer of the epithelium is already keratinized, the female is completely ready for fertilization;
- post-estrus (metaestrus) – the duration of this phase is 24–30 hours;
- Interestrus (diestrus) – lasts about 5 days.
After mating, the female develops an inguinal plug - an additional layer of tissue that protects the mouse from re-fertilization by another male.
There is no estrus during lactation. It resumes 25–30 days after birth, 2–3 days after the female stops feeding the pups.
Attention! When a mouse is ready to breed, it becomes restless and may even show aggression.
She takes a characteristic pose, slightly arching her back and raising her butt.
Cotton swab instead of a spoon
This decision was not easy. The mother already had a bad experience of feeding newborn mice. And I wasn’t at all attracted by the prospect of feeding them from a pipette every two hours... But there was nothing to do: three little lives depended on us.
In a warm house, the mice recovered and became more active. Unfortunately, we lost one of them almost immediately: either hypothermia affected him, or he was hit by a cultivator blade, but he died a few hours later. We fed the other two with a few drops of warm milk on a cotton swab (a pipette and a syringe without a needle are not suitable for this: they release the liquid in a stream that is too strong and the mouse can choke), and put them on a warm stove overnight.
Most of all, I was afraid that they would not survive until the morning: the metabolism of mice, especially small ones, is incredibly fast and in a few hours of “hunger” they could die from exhaustion. At 5 am, as soon as I woke up, I rushed to feed them. The little mice, smelling the milk, perked up and crawled around. The feeding was successful: each of them sucked 2-3 cotton wool dipped in milk. I didn’t know whether this diet was enough for them, but there was nothing else at hand.
So our mice lived for more than a day on the stove, from where I took them out to feed them.
When my husband and I were getting ready to go home, the mouse question came up sharply. On the one hand, I didn’t want to take them to the city (we both work, and it was not clear how to accommodate our schedule with their frequent feedings). But, on the other hand, my mother, who remained in the village, did not have any special formulas for feeding, and they were supposed to be needed in a couple of days. And I made up my mind: we took the mice home.
Pregnancy
During the first 7–10 days, it is impossible to determine pregnancy by visually examining the mouse; it looks the same as usual. The most obvious evidence of a female's pregnancy is the cessation of estrus. The behavior of rodents also changes - some females become calmer, while others, on the contrary, show irritability and aggressiveness. Gradually, the mouse’s appetite increases, it becomes less active, and begins to move more smoothly and carefully.
By the middle of the term, the mouse becomes rounder, its belly becomes larger, its nipples swell and become bright pink. The female begins to actively organize the nest - dragging sticks, hay, fluff, scraps of paper, small garbage.
Family
A fairly common problem in pregnant mice is toxicosis. It is manifested by loss of appetite, lethargy, increased salivation, and sometimes convulsions. The cause of this condition can be stress, poor nutrition, lack of fluids, and poor living conditions.
Pregnancy in wild and domestic mice proceeds almost identically. But most often, mice born at home are larger than their wild counterparts. This is due to the fact that pregnant mice in the wild eat worse and are also exposed to various stresses, while decorative mice spend their entire pregnancy in comfortable conditions, receiving a sufficient amount of nutritious, balanced food.
Varieties
There are different breeds of decorative mice. These include:
Micromys minutus (translated as “little mouse”) is the smallest mammal in Europe. The size of this rodent reaches 13 centimeters, and the tail and body are approximately the same length. The color of the back - from red to brown - is clearly distinguished from the color of the abdomen - white or light gray. They have a very mobile and grasping tail. The muzzle of these rodents, unlike their relatives, is shortened.
Gerbils. The second most popular breed, after baby mice. They are very similar to chipmunks because they have a body large enough for mice and a short drooping tail.
Spiny rodents. These mice look a little like hedgehogs. This is all because of their fur - it is shaped like needles. This breed is difficult to confuse with others, mainly because of the coat, but not only because of it. These mice also have very unusual ears and large black shiny eyes that look like beads.
Childbirth
Most often, mice give birth at night. Mice are born between midnight and 4 am. In rare cases, childbirth occurs in the evening between 16:00 and 20:00. Shortly before the start of labor, the female climbs into a pre-arranged nest. She does not need help, all actions are performed instinctively. The mouse takes the most comfortable position - most often it lies on its side, but it can also sit on the sacrum.
When labor begins and the first mouse appears, the female grabs it with her teeth and pulls it out. Then she gnaws through the membrane of the amniotic sac and gnaws the umbilical cord. After all the mice have appeared, the mouse carefully licks them and then eats the afterbirth.
Typically, if everything goes well, tiny mice are born every 5 minutes. If the delay is more than 15 minutes, then most likely the mouse is stuck, for example, due to its too large size. At home, a person helps a rodent in this situation; in nature, a mouse can die.
Kids
All mice give birth to one mouse at a time, but it is very difficult to say in advance how many there will be. How many pups a mouse gives birth to depends on the species and age of the female, and the number of births. Most often, a litter contains from 5 to 9 babies, but in general their number can vary from 1 to 15.
Newborn mice are naked, blind and deaf, their weight is about 1.5 g, and their size does not exceed 2 cm. Their skin is so thin that their insides can be seen through it.
Offspring
Immediately after hatching, the mice are blind, helpless and completely naked. The weight of each of them does not exceed one and a half grams. Babies need warmth and care. It is important not to disturb the female in the first days, not to touch the baby, so that the mother, under the influence of postpartum hormones and a protective reflex, does not eat her own cubs.
Already on the fourth day, the first fluff appears on the body of newborns, the pups begin to hear, as evidenced by the opening of the auricle. At the beginning of the second week of birth, the first teeth appear - usually the incisors of the lower jaw. And by the age of 14 days, the mouse becomes a fully formed teenager, no different from an adult. After a month, the grown offspring can be safely taken from the mother and transplanted into a new home.
How often do mice breed?
Living in comfortable conditions and eating normally, mice can give birth 12–14 times during the year. In mice living in the wild, mating occurs uncontrollably, but cold weather makes its own adjustments and reproduction is temporarily suspended.
In the case of decorative mice, the process of reproduction and the number of matings is regulated by the owner of the rodents. To avoid health problems, females are mated no more than 3-4 times a year.
But mice that illegally live in a house or a warm basement mate constantly, and newborn mice appear all year round.
On a note! In a year, a female can give birth to from 70 to 150 cubs.
Selection, preparation, rules of use for future parents
Successful reproduction largely depends on the correct selection of a pair. All candidates are carefully assessed, analyzing:
- constitution and physique;
- fatness;
- quality of the fur coat;
- fertility if mice have already been bred.
Both the female and the male must be strong, outwardly healthy, well-fed, but not obese.
If the female has already given birth, then the best is considered the one that:
- was a wonderful mother;
- brought an average number of mice;
- had a high lactation rate.
Animals that have a history of eating their offspring or animals that suffer from excessive aggression should not be allowed into breeding.
The female can be used no more than twice during the year.
Frequent childbirth significantly undermines health, and an unrestored body is unlikely to be able to provide future offspring with everything necessary for full development. Thus, it was noticed that the cubs of females who had exhausted their strength were born weak, developed poorly and died prematurely.
Males are also used wisely: frequent mating depletes reproductive function and the mouse may simply remain unfertilized.
Before mating, animals are provided with complete feeding with a sufficient amount of vitamins (especially E) and microelements.
Obese rodents, which most often turn out to be temporarily infertile, are forced to move as much as possible, and foods rich in carbohydrates are excluded from their diet.
There should be no more than ten females per male. They can be kept all together, but it is better to place each animal in its own cage, placing the females with the male as needed at the time of estrus.
Development of little mice
Despite the fact that newborn mice are very tiny and can navigate only by smell, they have an excellent appetite. They immediately find the mother's nipple and begin to eat. Baby mice grow very quickly. Moreover, usually, regardless of the number of pups in the litter, they develop at the same pace, since weak individuals that have no chance of survival are eaten by the mother soon after birth. Approximate development schedule for newborn mice:
- on the 3-4th day the first fluff appears on the body;
- on days 4-5, the ears open and rise;
- on days 6-7, almost the entire body is covered with fur and the first teeth begin to cut;
- On days 12-13, the eyes open.
In the third week of life, the mice finally develop all motor functions, they can run and eat solid food. After only 3-4 weeks, the pups become independent and can do without their mother.
Description of the rodent
Animals of this species are very tiny compared to rats. The body of an adult mouse reaches only 6.5-9.5 cm in length. The tail of a rodent is almost half as long as the body. It is covered with scales and small sparse hairs.
The average weight of an adult is only 12 to 30 grams. The ears are small and rounded. The color is predominantly dark, brownish-gray. On the belly, the fur is lighter and colored ash-gray or white.
Are you afraid of mice?
Very Not a drop
Habitat
The most ancient remains of a mouse were found in Western Asia, North Africa and the northern regions of India.
Traveling with people on ships, mice quickly spread throughout the world and received the status of “cosmopolitan animal.”
Interesting and educational facts about the life of rats
In India there is a Karni Mata temple where rats are revered, cared for and protected. If the rules for caring for a sacred animal and killing it are violated, this person is obliged to bring a golden figurine in the form of a rat to the temple.
In some American states, it is illegal to hit a rat with a baseball bat and can result in a $1,000 fine.
In Asian and African countries, rats are considered a worthy delicacy for a festive dinner. Rat meat is considered a delicacy.
A gray rat eats up to 12 kg of various cereal products per year. Experts have calculated that every year about 6 kg of one farmer’s harvest is spent on feeding one rat.
Sources
- https://notklop.ru/krysy/o-krysah/malenkie-krysyata/
- https://litbro.ru/gryzuny/mysh/mysh-malyutka
- https://litbro.ru/gryzuny/mysh/o-detenyshah-myshey
- https://1klop.com/chem-pohozha-i-otlichaetsya-myish-ot-kryisyi
- https://zelenyjmir.ru/krysa/
- https://litbro.ru/gryzuny/mysh/kak-otlichit-mysh-ot-krysy
- https://notklop.ru/krysy/o-krysah/krysy-i-myshi/
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Differences in behavior
If the pests were not caught red-handed, their presence can be determined by evidence. What is the difference between a mouse and a rat - the most important points.
Traces of a break-in
It is necessary to inspect the sites of sabotage. Rats are carnivores by nature. They prefer meat, lard, smoked meats, and carry bread, sausage, and cookies. They chew hard objects, preferring wood. They easily gnaw electrical wires and cords. They live near food waste and garbage cans.
Mice prefer grains, flour, sugar, cereals, and occasionally eat meat products. They leave behind damaged bags, plastic bags, newspapers, books, and leather goods. You can distinguish by these signs.
Footprints
They can freely talk about a pest that secretly hunts in the dark. The mouse leaves behind a chain of small steps located in close proximity to each other. The animal climbs well on shelves, window sills, cabinets, and rarely jumps. Mouse tracks in the snow are very clearly visible.
The rat moves with confident, long steps. If necessary, it can jump up to 1.5 m in height and up to 2 m in length. By this sign you can recognize the pest.
The footprints in the snow of a rat and a mouse are different: the former have round paw prints, while the rats have long ones.
On a note!
Rats rarely crawl into the house; they prefer outbuildings, cellars, warehouses, barns, sheds, and poultry houses. Don't mind eating chicken or gnawing on a pig's ears. Every farmer dreams of getting rid of rats in a chicken coop or barn. It can drag away a small puppy or kitten. If it enters a house, it usually hides under the floor. Mice love to live in human homes. They live in walls with insulation, under the floor, in the attic. At night you can often hear rustling sounds and the movement of small paws.
