Mice

views updated May 11 2018

Mice

New World mice

Deer mice

Old World mice

House mice

Wood mice

Spiny mice

Mice and humans

Resources

Mice are small fury mammals, usually living on the ground, with bright beady eyes, rounded ears, and long tails. Mice live all around the world, in almost every habitat, and are a very important part of nature. They are typically vegetarians, often eating seeds and grain, but some species have developed much more comprehensive diets. Known for their high rates of reproduction, females are normally pregnant for three or four weeks and give birth to multiple young. In most species, the young are naked, blind, and helpless at birth. Mice are an important source of food for numerous animals and are preyed upon by a wide variety of predators, ranging from owls to weasels. Mice also impact humans in a variety of ways.

Belonging to the order Rodentia, mice, along with other types of rodents, are further classified in the suborder Myomoxpha. This is a huge suborder. In fact, more than one quarter of all mammal species on Earth belong to the suborder Myomorpha, which includes five families: rats and mice (Muridae), dormice (Gliridae and Seleviniidae), jerboas (Dipodidae), and jumping mice and birch mice (Zapodidae). The family Muridae is the largest family, containing 1,082 species of mice, rats, voles, lemmings, hamsters and gerbils. While there are 14 subfamilies within this family, the vast majority of these species belong to four subfamilies: the New World rats and mice (Hesperomyinae), the Old World rats and mice (Murinae), gerbils (Gerbillinae), and voles and lemmings (Microtinae).

New World mice

Containing about 350 species, the subfamily of New World mice is the largest mammalian group. Members live in a wide range of habitats thriving in deserts, on mountains, in humid forests, and even on ice-bound plains. Geographically, they live as far north as the southern reaches of the North Pole and as far south as Patagonia, which is the southern tip of South America. Most New World mice live on the ground, however some burrow into it, some live in semi-aquatic conditions, and some even live in trees. The climbing mouse (Rhipidomys venezuelae ), for instance, builds its nests in burrows beneath the roots of trees in the forests of South America but spends a lot of its life in the treetops.

Like most mice, New World mice are usually vegetarians, although some have adapted to eating small animals. For example, the northern grasshopper mouse, living in North America, is largely carnivorous.

Dieting primarily on grasshoppers and scorpions, on occasion this mouse may even eat other mice.

Deer mice

A species of white-footed mouse, the deer mouse (Peromyscus maniculatus ) is the most common kind of New World mouse, and includes around 65 subspecies. Their bodies range in size from 4.75-8.5 in (12-22 cm), and their tails measure between 3.25-7 in (8-18 cm). Deer mice are probably the most abundant mammal in the western United States. These mice eat both plants and insects and are most active at night.

They are noted for their practice of gathering large quantities of food and hiding it in numerous locations to see them through times of bad weather. Since they do not hibernate, this practice is essential to their survival. Deer mice are quite fertile; they are able to bear young at seven weeks old and have litters of up to nine young after a pregnancy lasting three or four weeks.

Old World mice

Containing almost 400 different species, the subfamily of Old World mice includes mice and rats that are highly adaptable and tolerant of adverse natural environments. Oftentimes pests, these mice eat grains and crops, and can carry diseases. Three very interesting groups of Old World mice are the house mice, the wood mice, and spiny mice.

House mice

The most common Old World mouse is the house mouse (Mus spp.). A genus originating in southern Asia, the house mouse includes about 44 separate species; only one species is found in the United States. The body of the house mouse measures about 2.5-3.75 in (6-10 cm) long and is covered by brownish gray fur. Its tail, naked and scaly, typically measures about the same length as its body. Its ears and legs are fairly large.

One of the oldest known domestic rodent pests, house mice have adapted their lives to human habitats. Often living in buildings and making nests behind paneling and beneath floorboards, house mice thrive in large cities and on farms. These mice are able to breed at three months old and have life spans of about four years. Typically, in a given year, a female house mouse can bear from four to six litters of four to eight young, although it is not unheard of for a litter to contain as many as 13 young. Like many other species of mice, the gestation period lasts three weeks and the young are born bald with their eyes shut. At about 13 days old, their eyes open, and fine hair covers their bodies. While the young initially start to feed on their own at around 17 days old, they nurse from their mothers until they are four weeks old. Interestingly, when a population of house mice grows too large for a given area, a form of natural birth control takes effect. Reproductive rates fall dramatically because adolescent females become infertile as their reproductive organs fail to mature or become inactive.

House mice live in family groups. The mice commonly groom each other, particularly on the backs of their necks where they are unable to groom themselves. Mutual grooming occurs daily in most mouse families. Within these family groups, the males have clearly defined ranks. These rankings are not indisputable, however. House mice fight and display threatening and submissive postures.

These social standings are directed at protecting the mices territory, which the mice outline with their urine. Within the territory, the animals are able to live alone and build their nests, but they do not delineate their own smaller territories within the larger one. The house mouse territory provides the inhabitants with common escape holes and areas for urinating and defecating. The territory can be quite small as long as it provides the mice adequate food and shelter. In fact, the activities of the house mouse can be restricted to an area of only a few square yards. Every night, each mouse within the group typically investigates the entire territory to discover changes that have occurred during the day.

These mice are more active during the night, although they sometimes alternate between periods of rest and activity up to 20 times each day. Furthermore, they are able to move about in many different ways. Preferring not to go into the water, house mice are still able to swim, as well as to run, jump, and climb. Their sense of hearing is very good. They hear very high tones well, a useful ability when listening to other mice squeak, but are much less attuned to lower notes. Their sense of smell is also keen, enabling them to find food and know their territorial boundaries.

Because the many different subspecies have developed slightly different behaviors, they have been able to adapt to any place that man lives. Often, house mice live in hiding places near human food, even inside bags of grain. Because they live near mans own stores, these mice do not typically store their food. They gnaw their way into food storage containers, eating as much as they can stomach and spoiling even more. Although they prefer to eat grains and grain products, house mice can eat practically anything.

The most important European subspecies are the western house mouse (Mus musculus domesticus ), found in northwestern Europe, and the northern house mouse (Mus musculus musculus ), found in eastern, northeastern, and southeastern Europe. While these subspecies of house mice originated in Europe, they quickly spread as Europeans moved to other parts of the globe. The western house mouse lives almost exclusively in houses or other manmade structures, while the northern house mouse spends part of the year outside. Both subspecies are descended from wild subspecies.

Wood mice

Unlike the house mouse, some species of Old World mice live in fields and woods and rarely bother humans, for example, the wood mouse (Apodemus spp.). Wood mice are found as far south as Morocco reaching as far north as Iceland and are common throughout Europe and Scandinavia as well as Asia. Of the eleven species that have been identified, five live in Europe. Wood mice are similar in appearance to house mice but have bigger ears, longer hind legs, and their eyes protrude more noticeably. Their bodies range in size from 3-5 in (8-13 cm), and their tails are usually the same lengths as their bodies. Their soft hair comes in a variety of colors.

Nocturnal animals, wood mice live anywhere there is sufficient ground cover in which to hide from predators and to get foodparticularly, on the edge of forests. Making their nests under tree roots, these mice leave their nests in the evenings and, in pairs, forage for seeds, berries, grubs, and other insects. If the weather is mild, these mice can breed rapidly, sometimes having four litters each year with an average of five young.

Spiny mice

Another interesting genus of Old World mice in the spiny mouse (Acomys spp.). As the name implies, their backs are covered with spiny, bristle like hairs. These mice live throughout the dry environments of northern India and Africa; specifically, they live in deserts, prairies, and savannas. One species lives on the island of Crete in the Mediterranean Sea. They normally eat dried plants, small insects and spiders, and have even been discovered eating the dried remains of Egyptian mummies.

Like their fur, their tails are spiny. Notably, like lizards, their tails can be broken from their bodies rather easily. When a predator catches this mouse, it is often very surprised when it is left with only the animals tail. Unlike lizards, however, the spiny mice can never grow tails to replace the ones they lose.

The breeding behavior of spiny mice and their maturity level at birth are significantly different from other species of mice. Spiny mice are pregnant for five or six weeks, rather than the three to four week period experienced by other mice. During the birth, other female spiny mice in the group help with the delivery process by chewing through the umbilical cord and by licking the placentas from the newborns. Often, these midwives try to claim the young as their own. A few days later, however, the young are treated as the common children of the community, nursed by every mother and accepted everywhere. Incredibly, the new mother is fertile again by the evening of the same day she delivers and is usually re-impregnated at this time. Unlike other mice, spiny mice are not naked, blind, and helpless at birth. Instead, they appear strong, covered with sparse hair, and their eyes are usually open. At three days old, they start to investigate their surroundings.

Mice and humans

House mice, as well as other species, have been linked to man for thousands of years. Their destruction of human food supplies and crops has been recorded in very early records. Importantly, these mice are also responsible for spreading a number of diseases, such as typhus, spotted fever, and Salmonella food poisoning.

While many of their activities definitely have had a negative impact on humans, mice have also been provided a useful service. Ever since their importation to Europe from Japan in the mid-1900s, house mice, and some other species, have been used as laboratory animals for research in medicine and biology. In particular, mice are used to study human genetics, to test the effects of various drugs, and to follow the development of certain viruses. Furthermore, mice are used in human pregnancy tests, and they help doctors better understand the way that cancer effects humans. Probably, the most commonly used species is the white mouse, an albino form of the house mouse.

Resources

BOOKS

Alderton, David. Rodents of the World. New York: Facts on File, 1996.

Nowak, R.M. ed. Walkers Mammals of the World. 6th ed. Baltimore: John Hopkins University Press, 1999.

Wilson, D.E. and D. Reeder, comp. Mammal Species of the World. 3rd ed. Washington, DC: Smithsonian Institution Press, 2005.

Kathryn Snavely

Mice

views updated May 11 2018

Mice

Mice are small fury mammals , usually living on the ground, with bright beady eyes, rounded ears, and long tails. Mice live all around the world, in almost every habitat , and are a very important part of nature. They are typically vegetarians, often eating seeds and grain, but some species have developed much more comprehensive diets. Known for their high rates of reproduction, females are normally pregnant for three or four weeks and give birth to multiple young. In most species, the young are naked, blind, and helpless at birth. Mice are an important source of food for numerous animals and are preyed upon by a wide variety of predators, ranging from owls to weasels . Mice also impact humans in a variety of ways.

Belonging to the order Rodentia, mice, along with other types of rodents , are further classified in the suborder Myomoxpha. This is a huge suborder. In fact, more than one quarter of all mammal species on Earth belong to the suborder Myomorpha, which includes five families: rats and mice (Muridae), dormice (Gliridae and Seleviniidae), jerboas (Dipodidae), and jumping mice and birch mice (Zapodidae). The family Muridae is the largest family, containing 1,082 species of mice, rats, voles , lemmings , hamsters and gerbils . While there are 14 subfamilies within this family, the vast majority of these species belong to four subfamilies: the New World rats and mice (Hesperomyinae), the Old World rats and mice (Murinae), gerbils (Gerbillinae), and voles and lemmings (Microtinae).


New World mice (Hesperomyinae)

Containing about 350 species, the subfamily of New World mice is the largest mammalian group. Members live in a wide range of habitats thriving in deserts, on mountains , in humid forests , and even on ice-bound plains. Geographically, they live as far north as the southern reaches of the North Pole and as far south as Patagonia, which is the southern tip of South America . Most New World mice live on the ground, however some burrow into it, some live in semi-aquatic conditions, and some even live in trees. The Climbing mouse (Rhipidomys venezuelae), for instance, builds its nests in burrows beneath the roots of trees in the forests of South America but spends a lot of its life in the treetops.

Like most mice, New World mice are usually vegetarians, although some have adapted to eating small animals. For example, the northern grasshopper mouse, living in North America , is largely carnivorous. Dieting primarily on grasshoppers and scorpions, on occasion this mouse may even eat other mice.


Deer mice

A species of white-footed mice, the deer mouse (Peromyscus maniculatus) is the most common kind of New World mice, including around 65 subspecies. Their bodies range in size from 4.75-8.5 in (12-22 cm), and their tails measure between 3.25-7 in (8-18 cm). Deer mice are probably the most abundant mammal in the western United States. These mice eat both plants and insects and are most active at night.

They are noted for their practice of gathering large quantities of food and hiding it in numerous locations to see them through times of bad weather . Since they do not hibernate, this practice is essential to their survival. Deer mice are quite fertile; they are able to bear young at seven weeks old and have litters of up to nine young after a pregnancy lasting three or four weeks.

Old World mice (Murinae)

Containing almost 400 different species, the subfamily of Old World mice includes mice and rats that are highly adaptable and tolerant of adverse natural environments. Oftentimes pests , these mice eat grains and crops , and can carry diseases. Three very interesting groups of Old World mice are the house mice, the wood mice, and spiny mice.


House mice

The most common species of Old World mice is the house mouse (Mus). A genus originating in southern Asia , the house mouse includes about 44 separate species; only one species is found in the United States. The body of the house mouse measures about 2.5-3.75 in (6-10 cm) long and is covered by brownish gray fur. Its tail, naked and scaly, typically measures about the same length as its body. Its ears and legs are fairly large.

One of the oldest known forms of domestic rodent pests, house mice have adapted their lives to human habitats. Often living in buildings and making nests behind paneling and beneath floorboards, house mice thrive in large cities and on farms. These mice are able to breed at three months old and have life spans of about four years. Typically, in a given year, a female house mouse can bear from four to six litters of four to eight young, although it is not unheard of for a litter to contain as many as 13 young. Like many other species of mice, the gestation period lasts three weeks and the young are born bald with their eyes shut. At about 13 days old, their eyes open, and fine hair covers their bodies. While the young initially start to feed on their own at around 17 days old, they nurse from their mothers until they are four weeks old. Interestingly, when a population of house mice grows too large for a given area, a form of natural birth control takes effect. Reproductive rates fall dramatically because adolescent females become infertile as their reproductive organs fail to mature or become inactive.

House mice live in family groups. The mice commonly groom each other, particularly on the backs of their necks where they are unable to groom themselves. Mutual grooming occurs daily in most mouse families. Within these family groups, the males have clearly defined ranks. These rankings are not indisputable, however. House mice fight and display threatening and submissive postures.

These social standings are directed at protecting the mice's territory, which the mice outline with their urine. Within the territory, the animals are able to live alone and build their nests, but they do not delineate their own smaller territories within the larger one. The house mouse territory provides the inhabitants with common escape holes and areas for urinating and defecating. The territory can be quite small as long as it provides the mice adequate food and shelter. In fact, the activities of the house mouse can be restricted to an area of only a few square yards. Every night, each mouse within the group typically investigates the entire territory to discover changes that have occurred during the day.

These mice are more active during the night, although they sometimes alternate between periods of rest and activity up to 20 times each day. Furthermore, they are able to move about in many different ways. Preferring not to go into the water , house mice are still able to swim, as well as to run, jump, and climb. Their sense of hearing is very good. They hear very high tones well, a useful ability when listening to other mice squeak, but are much less attuned to lower notes. Their sense of smell is also keen, enabling them to find food and know their territorial boundaries.

Because the many different subspecies have developed slightly different behaviors, they have been able to adapt to any place that man lives. Often, house mice live in hiding places near human food, even inside bags of grain. Because they live near man's own stores, these mice do not typically store their food. They gnaw their way into food storage containers, eating as much as they can stomach and spoiling even more. Although they prefer to eat grains and grain products, house mice can eat practically anything.

The most important European subspecies are the western house mouse (Mus musculus domesticus), found in northwestern Europe , and the northern house mouse (Mus musculus musculus), found in eastern, northeastern, and southeastern Europe. While these subspecies of house mice originated in Europe, they quickly spread as Europeans moved to other parts of the globe. The western house mouse lives almost exclusively in houses or other manmade structures, while the northern house mouse spends part of the year outside. Both subspecies are descended from wild subspecies.


Wood mice

Unlike the house mouse, some species of Old World mice live in fields and woods and rarely bother humans. One such species is the wood mouse (Apodemus). Wood mice are found as far south as Morocco reaching as far north as Iceland and are common throughout Europe and Scandinavia as well as Asia. Of the eleven species that have been identified, five live in Europe. Wood mice are similar in appearance to house mice but have bigger ears, longer hind legs, and their eyes protrude more noticeably. Their bodies range in size from 3-5 in (8-13 cm), and their tails are usually the same lengths as their bodies. Their soft hair comes in a variety of colors.

Nocturnal animals, wood mice live anywhere there is sufficient ground cover in which to hide from predators and to get food—particularly, on the edge of forests. Making their nests under tree roots, these mice leave their nests in the evenings and, in pairs, forage for seeds, berries, grubs, and other insects. If the weather is mild, these mice can breed rapidly, sometimes having four litters each year with an average of five young.


Spiny mice

Another interesting species of Old World mice in the spiny mouse (Acomys). As the name implies, their backs are covered with spiny, bristle-like hairs. These mice live throughout the dry environments of northern India and Africa ; specifically, they live in deserts, prairies, and savannas. One species lives on the island of Crete in the Mediterranean Sea. They normally eat dried plants, small insects and spiders, and have even been discovered eating the dried remains of Egyptian mummies.

Like their fur, their tails are spiny. Notably, like lizards, their tails can be broken from their bodies rather easily. When a predator catches this mouse, it is often very surprised when it is left with only the animal's tail. Unlike lizards, however, the spiny mice can never grow tails to replace the ones they lose.

The breeding behavior of spiny mice and their maturity level at birth are significantly different from other species of mice. Spiny mice are pregnant for five or six weeks, rather than the three to four week period experienced by other mice During the birth of offspring, other female spiny mice in the group help with the delivery process by chewing through the umbilical cord and by licking the placentas from the newborns. Often, these "midwives" try to claim the young as their own. A few days later, however, the young are treated as the common children of the community, nursed by every mother and accepted everywhere. Incredibly, the new mother is fertile again by the evening of the same day she delivers and is usually re-impregnated at this time. Unlike other mice, spiny mice are not naked, blind, and helpless at birth. Instead, they appear strong, covered with sparse hair, and their eyes are usually open. At three days old, they start to investigate their surroundings.


Mice and humans

House mice, as well as other species, have been linked to man for thousands of years. Their destruction of human food supplies and crops has been recorded in very early records. Importantly, these mice are also responsible for spreading a number of diseases, such as typhus , spotted fever, Salmonella food poisoning , and bubonic plague .

While many of their activities definitely have had a negative impact on humans, mice have also been provided a useful service. Ever since their importation to Europe from Japan in the mid-1900s, house mice, and some other species, have been used as laboratory animals for research in medicine and biology . In particular, mice are used to study human genetics , to test the effects of various drugs, and to follow the development of certain viruses. Furthermore, mice are used in human pregnancy tests, and they help doctors better understand the way that cancer effects humans. Probably, the most commonly used species is the white mouse, an albino form of the house mouse.

Kathryn Snavely

mice

views updated May 29 2018

mice / mīs/ • plural form of mouse.

MICE

views updated Jun 27 2018

MICE Member of the Institution of Civil Engineers