Mice are small rodents, belonging to the genus Mus. The best known mouse species is the common house mouse, but the term itself is also applied to species outside of this genus, in reference to any other small rodents. Larger rodents are generally referred to using the term “rat”. Although some people often confuse them, mice are completely different from rats. The distinction can be easily seen in the fact that rats are larger, have a cylindrical shape, and can sometimes be bald.
There are thirty known species of mice, and the most common one is the house mouse (Mus musculus). This does not mean, however, that this is the only mouse that can live indoors; the American white-footed mouse (Peromyscus leucopus), the deer mouse (Peromyscus maniculatus), as well as so-called domestic mice (the ones that people hold as pets) are only some of the species of mice that can also be found indoors. Other common species of mice include the field mouse (Apodemus flavicollis), the wood mouse (Apodemus sylvaticus), the dormouse (Muscardinus avellanarius), the spiny mouse, and the zebra mouse.
Description and distribution of mice
Mice have a small, pointed snout, small rounded ears, and a long, scaly tail. Their ears allow them to have excellent hearing, which, in turn, is a helpful asset when being extremely quiet. Although this is not applicable to all the species, most mice also have relatively good eyesight. Even those that do, however, still mostly rely on their whiskers to sense out the environment around them, detecting smooth and rough edges, temperature change, as well as wind.
Typical colors are white, grey, and brown, however, color and size are characteristics that vary according to each specie. Mice typically grow from 1 to 7 inches (2.54 to 18 centimeters) in length and weigh between 0.5 and 1 ounce (230 g to 280 g). The smallest species of mice on the planet is the African pygmy, measuring only 3 – 7,8cm and weighing less than 10g. It should be noted, however, that a mouse’s size does not usually include its tail, which can, in some instances, be as long as the body itself. The house mouse is light grey or brown in color, can grow up to 20cm (nose to tail) and can weigh between 12g-30g. The deer mouse, the second most common species of mice that can be found indoors, is brown-red in color, with a white underbelly and it can grow up to 7-10cm (nose to tail) and can be identified by its large ears and black, beady eyes.
Mice are remarkably resilient, able to adapt to almost any environment on Earth, so it should come as no surprise that they are considered to be one of the most successful mammalian genera in existence. They can be found in nearly every country and can easily survive in nearly every habitat, living in forests, grasslands, manmade structures, etc. These rodents are primarily nocturnal, and enjoy sleeping during the day, being able to do so for up to 12 hours. This is why pet mice or house mice can be heard playing or foraging during the night. Although most species are unable to see extremely well, they do compensate through a very well developed sense of hearing and of smell, both of which are used to locate food, as well as sense potential enemies.
Mice are intelligent creatures. They communicate in complex ways, through both vocal (often ultrasonic, beyond the auditory range of humans) and odorous means (through pheromones). Interestingly, they are considered to be among the most talkative creatures, as they also have facial expressions, which communicate moods. Although most wild rats are timid towards humans, as well as other animals, they are usually quite friendly amongst themselves. It is because of this social nature that domestic mice are happier if they have at least one other mouse in close vicinity. A group of wild mice are, perhaps aptly, referred to as a “mischief”.
Despite their sociable behavior, mice are very territorial, with each member of the group being assigned a relatively small living area. Because of this, mice will generally not travel further than 8m, even in search of food. They mark their territory with urine and, every night, examine it to see if anything has changed. It is this prudent nature that prevents most mice from walking into a trap right away.
In the wild, mice build intricate burrows, typically with long, tight entrances and various escape routes. Interestingly, in at least one species, researchers have found that the architectural design of a burrow is transmitted genetically. Within these homes, mice have been found to be very clean and organized, having specific areas dedicated to storing food, going to the toilet, as well as sheltering in case of danger. As mentioned above, mice generally remain close to home, only venturing up to 3-8m away in search of food. Young mice, however, are very curious, keen on exploration. Consequently, they will often be found squeezing through the smallest of gaps and biting through the toughest of obstacles.
They are also small, but resilient creatures. Mice have great balance, being able to walk along very thin pieces of rope or wire, as well as scale vertical surfaces. What’s more, they can jump down 3-4 m without even injuring themselves. Interestingly, some mice feed on scorpions, and are able to withstand multiple scorpion bites. When it comes to actual defense strategies, most mice will play dead until they feel that whatever possible predator scared them has left. Otherwise, different species may have different tactics, depending on the predators they are dealing with and the environment they live in. A wood mouse, for example, can shed its tail if it is caught by a predator, in this way managing to escape.
Breeding and dietary information of mice
Mice have a very high breeding rate. They are polyestrous, coming in heat very often. Ovulation is spontaneous, and, as a result, mice are able to breed all year round. The average gestation period lasts around 20 days, and the average number of younglings (called pups) ranges from 10-12. These are completely defenseless at birth, being hairless, blind, and deaf, and weighing barely 0.5g. They grow quickly and are weaned at around 3 weeks of age, when they generally weigh around 10-12g. The female is able to reproduce again in 2-5 days, and can, in this way, have up to 5-10 litters each year. Both males and females then become able to reproduce at around 50 days old. Common terms used to refer to different ages/sizes of mice when sold for pet food are “pinkies”, “fuzzies”, “crawlers”, “hoppers”, and “adults”. Pinkies are newborn mice that have not yet grown fur; fuzzies have some fur but are not very mobile; hoppers have a full coat of hair and are fully mobile but are smaller than adult mice.
In the wild, mice are largely herbivores, feeding on any sort of fruit, vegetable, plant, or grain. However, famous as they are for their adaptability, urban mice can feed on all sorts of food scraps, including meat. In captivity, mice are commonly fed commercial pelleted mouse diet. These diets are nutritionally complete, but they still need a large variety of vegetables. If food is very scarce, wild mice will even eat each other. Contrary to what is shown in cartoons, mice do not generally eat cheese. A second misconception concerns the chewed up wires, insulation, books, and papers that people whose house is infested with mice find; mice do not eat these items, but chew them into pieces so that they can then use them to build nests.
Healthy food intake is generally 15g per 100g of body weight per day, while healthy water intake is generally 15ml per 100g of body weight per day. Because of this voracious appetite, mice need to eat around 15-20 times a day, which is the reason why they tend, as much as possible, to build homes close to food sources.
Mice are also part of the diet of many small carnivores. In various countries mice are used as food for pets such as snakes, lizards, frogs, tarantulas and birds of prey, and many pet stores carry mice for this purpose. Mice without fur are easier for the animal to consume; however, mice with fur may be more convincing as animal feed. Mice are also preyed on by a variety of animals, including: some arthropods, certain birds of prey, cats, foxes, snakes, wild dogs. Wild mice can usually only live for around 1-2,5 years. Domestic mice, on the other hand, have a lifespan of up to 6 years.
Mice as pests
Mice are known to invade homes in search of food and shelter, especially when the cold season approaches. Being rodents, they can cause structural damage, as well as spread diseases through parasites, urine, and faeces. Mice are known to carry as many as 200 pathogens. In North America, breathing in dust that has come in contact with mouse excrements has been correlated with the hantavirus, which can lead to hantavirus pulmonary syndrome (HPS).
They can also they can also cause serious property damage by chewing on materials. In fact, they have been known to spark electrical fires by gnawing on wires inside homes and behind walls. House mice can also eat and contaminate stored food, and are a vector of Salmonella, tapeworms, and the plague (via fleas), among other dangerous organisms. These parasites bite the infected mouse and then spread the disease by biting humans. Even the smallest amount of mouse urine can trigger allergies, particularly in children because their immune systems are still developing. Mice spread disease through bite wounds and by contaminating food and water with their waste products.
Mice are well recognised for invading households, poultry runs and buildings where they consume and foul food sources damage infrastructure. They can also cause damage crop paddocks immediately after sowing by digging into loose soil to find larger seeds such as maize, sunflower, wheat, oats, barley, pulses, pumpkin and marrow. They also eat the newly sprouted seedlings before and after they emerge from the soil. The impact of mice is not as great on plants beyond the seedling stage, at least not until seeds or grains begin to mature. Plants such as wheat are then damaged by mice gnawing at the nodes on the stems causing developing seed heads to fall. In maturing crops of wheat, oats, barley, pulses, sorghum and maize, losses of up to 30 per cent have been reported. Heavy losses can also occur in vineyards and vegetable crops from eating and fouling of the produce.
However, mice can also be considered useful to humans. A well-known fact, is that mice are used in laboratory research in fields such as biology and psychology. In fact, they are the most commonly used mammalian model organism, even more common than even rats. This is because they are mammals, and thus present many biological similarities with humans, with every mouse gene having a human homolog. Furthermore, they are inexpensive, relatively easy to feed and care for, and have high breeding rates; if raised from birth or given sufficient human contact, mice are also very docile, as they are often kept as pets as well. These so-called domestic mice are often different from the common house mouse in appearance and behavior, most notably, in breeding. All rats can become used to being handled by humans, but domestic rats are inherently friendly, playful, and even loving, making good pets for older children and adults.
The house mouse is the most commonly encountered rodent in the U.S. It can adapt quickly to changing conditions and breeds rapidly. Should you be dealing with a mouse infestation, whether it is inside you house or affecting your crops, you need to know how to get rid of mice infestation, but also you need to know how to prevent such an infestation and how to keep mice away from your house, yard or crops.