Rats, mice, and relatives III

Old World rats and mice (Murinae)

Class Mammalia

Order Rodentia

Suborder Sciurognathi

Family Muridae

Subfamily Murinae

Thumbnail description
Old World rats and mice can grow up to the size of rabbits and have long tails, either furry or scaly, sometimes longer than the body itself; aquatic species may use their tails as rudders and others use their tails and unique opposable digits on their front feet to climb; characteristics vary widely, but all Murinae have a row of tubercles on the inside of their upper molars

Size
1.9–14.7 in (5–36 cm); 0.2–52.9 oz (5–1,500 g)

Number of genera, species
122 genera; 529 species, with more identified annually

Habitat
Forests, fields, bushes, flatlands, steppes, etc.; some are aquatic, some live in burrows, tunnels, beneath logs or other forms of shelter, or in nests; also can live in trees, in sewers and cellars, and in various parts of houses

Conservation status
Critically Endangered: 18 species; Endangered: 33 species; Vulnerable: 56 species

Distribution
Worldwide

Evolution and systematics

The Muridae family contains 25% of all living mammals, and it appeared in the fossil record during the Upper Miocene (10–15 million years ago [mya]). Recent molecular evidence has supported the belief that the family radiated quickly and suddenly, which, as a result, has caused a lack of consensus in the scientific community about the evolution of the family and its subfamilies. One relationship to be addressed in murine systematics is the difference between rats and mice. In general, animals that have a body length of less than 5.1–5.9 in (13–15 cm) are called mice, and rats are those that are larger. Still, rats and mice diverged about 12 mya, and scientists believe that murines evolved from rodents in Eurasia.

Physical characteristics

The smallest murines, like the African native mice, only reach 1.9 in (5 cm), while the largest can grow significantly bigger. The greater bandicoot rats (Bandicota), for example, can have a body length of 14.7 in (36 cm) and can weigh up to 3.3 lb (1.5 kg). In some cases, their tails are semi-prehensile and assist in climbing, and can either be scaly or slightly

furred. They can have opposable thumb knobs, and their bodies are adapted for climbing (strong feet and semi-prehensile tails), jumping (long hind feet), or swimming (using their tails as rudders). They have, in general, 16 teeth (I1/0 C0/0 P03/1 M0/0-3), and their rooted molars are either laminate or cuspidate. Females have 4–24 nipples.

Distribution

The murine rodents are endemic to the Old World, including Eurasia, Africa, and Australiasia, but human intervention has spread many species throughout the Americas and across the world. Some murine rodents have even established populations in Antarctica.

Habitat

The animals can live in a variety of habitats, from arid deserts to the jungles of the Indo-Pacific. Many of the rodents have become commensal with humans and are known to be pests. Murines live in nests or burrows, either in trees, on the ground, or in and around houses. Certain murine rodents, like the brown rat, are known to live in burrows, which has led animal biologists to study them in mazes—which simulate their natural habitat—in order to understand how

they find their way and how they learn. Once put in a maze with food at the end, brown rats will search through the maze and make a series of errors, but eventually will run at high speed, without deviations, directly to the end. They also can find their way in lit and dark mazes, are not confused by inclined floors, and it is speculated that they use their whiskers to feel the walls, and even listen to the echoes of their noises off the walls of the maze to orient themselves. They perform better in mazes than humans, which has lead scientists to believe that the rats have memories and minds conditioned, from living in underground tunnels, to a sort of navigation.

Behavior

Old World rats and mice can be social creatures. They are known to travel in groups (hence the term "rat packs") and sleep together peacefully, but can be aggressive towards members of other rat colonies and are known to form colonial territories. Scientists have identified up to 20 pheromones that rats use to attract mates, as well as other scents that the animals use to mark territory or objects.

Rats are also vocal creatures and emit various sounds. Encounters between brown rats, for example, may begin with percussive chattering, while bush rats scream and whistle at each other.

Feeding ecology and diet

These animals can be nocturnal or diurnal and exhibit a wide range of foraging behavior and food preferences. Some species feed only on nuts and berries, while other species have been known to gnaw on just about anything. They often forage or

hunt in packs, and certain species are known to be able to catch birds. Aquatic species hunt fish.

Reproductive biology

These animals are some of the most successful rodents in the world, in part because they reproduce frequently. Murid rodent pups, the murines included, are usually born naked and blind. For the most part, their eyes open and they grow hair within a week or two, and they are weaned shortly thereafter. A common behavior among these rodents is that the mothers carry their young on their nipples, which allows them

to flee from danger without making multiple trips to carry the pups to safety. When conditions are optimal, they generally are able to mate year-round.

Conservation status

The murine rats are one of the most hardy mammalian species. They reproduce often and in great numbers and are highly adaptable to many environments. However, there are a

few species that are in need of conservation action if they are to survive. Generalist species such as the black rat and brown rat are not imperiled, but certain rats, especially those endemic to island ecosystems, have faced habitat destruction by man and animals. A total of 18 species are on the verge of extinction and are classified as Critically Endangered by the IUCN.

Significance to humans

Old World rats have a long history with humans. Some are seen as cuddly pets, like the spiny rats (genus Echimys), while others are considered pests that eat stored food and are indirectly responsible for killing millions of people by spreading the black plague, typhus, and other maladies. However, these pestilent creatures have become invaluable to humans: the common lab rats and mice are descendents of the murines. These animals have been, and will continue to be, essential research animals, and many of the major discoveries in medical psychological and research are a direct result of the murines and their healthy ability to reproduce.

Species accounts

List of Species

House mouse

Mus musculus

taxonomy

Mus musculus Linnaeus, 1758, Uppsala, Sweden.

other common names

English: Mouse; French: Souris domestique; German: Hausmaus; Spanish: Ratón común.

physical characteristics

Body length 5.1–9 in (13–20 cm); tail 2.3–3.9 in (6–10 cm); weight 0.6–0.8 oz (18–23 g). A typical, stereotypical mouse, with grayish brown hair on its top, relatively big ears, and a dusky, scaly, nearly hairless tail; the fur on its bottom is only slightly lighter than the fur on its top, and it has ungrooved incisors.

distribution

Mice spread to Europe from Asia and appeared in the sixteenth century in the New World on the ships of explorers. In the seventeenth century, they appeared in northern North America and have proliferated since due to high reproductive capacity. House mouse subspecies can be found across the world.

habitat

Underground burrows, which some subspecies equip with storage rooms. Each mouse will make its own nest, but will share burrows with other individuals in the colony. Many house mice are co-habitants with humans, living beneath large appliances or inside of walls in human homes. Some house mice live temporarily in grain fields, which they migrate into, breed, feed, and leave when the field is plowed; in 1926–1927, house mice nearly took over the fields of California's Central Valley, living in them in a density of 202,000 mice per 2.5 acres (1 ha). Sometimes, they eat animal and plant pests in the fields, but they inevitably wind up in barns and silos where they tend to contaminate food. In general, the house mouse does not stray far from cover, with the best habitat offering copious amounts of food, water, and places to hide. Their home ranges vary, from 120 ft (36.5 m) for some indoor mice to more than 2 mi (3.2 km) for certain ones outside.

behavior

A social species, it lives in groups with others of its kind, and aggressive males have hierarchical ranks and tend to dominate colonies. Each group lives in a territory bound by scent markers, and animals within the colony have their own nests. They will groom each other and display aggressive and submissive postures common in the species.

feeding ecology and diet

Eat up to 10% of their body weight daily, and feed up to 20 times each day. They consume grains, fruits, vegetables, meat, insects, and have been known to eat glue, paste, and even soap. If they eat moist food or a seed diet of 12% protein, they can live without water. The house mouse has been known to feed on caterpillars, flightless moths, and earthworms.

reproductive biology

Polygynous. They reproduce copiously, and a biological contraceptive keeps their populations in check: females' ovaries become inoperative and the animals become infertile. They breed throughout the year, with females giving birth to litters of 3–12 offspring about 5–10 times annually. Gestation is about three weeks. When the young arrive, they are hairless and their eyes are closed. Young are weaned by 21 days, they begin to reproduce in their second month of life, and they can live, depending on predation, to be six years old. Most wild mice live about a year, while those in captivity generally live about two years.

conservation status

Not threatened.

significance to humans

Over the centuries, they have spread disease and have been used by scientists to help cure disease. The albino lab mouse, the icon of scientific lab research, was bred from the house mouse and has been used in everything from cancer studies to stem cell research. At one point, cooked mouse was a folk remedy for flu-like symptoms, and house mice were considered a helper for conditions like baldness and constipation. They also carry a variety of germs and viruses that are dangerous to humans, including tularemia, bubonic plague, spotted fever, typhus, and Salmonella.

Black rat

Rattus rattus

taxonomy

Rattus rattus (Linnaeus, 1758), Uppsala, Sweden.

other common names

English: House rat, ship rat; French: Rat noir, rat commun; German: Hausratte; Spanish: Rata de los techos, rata común.

physical characteristics

Body length 6.3–8.6 in (16–22 cm); tail 6.7–9.8 in (17–25 cm); weight (70–300 g). Its tail is always longer than its relatively slender body, and it has very large ears. Several subspecies exist, with various colorings: one has black fur on the top and gray fur on the bottom of the animal; one is agouti above and white below; and one is agouti above and slate below. The animal occasionally has a white spot on its chest.

distribution

Has spread throughout the world, though it is likely native to peninsular India.

habitat

Found around the world because they tended to become stowaways on ships, it is believed that more than 90% of rats on ships were black rats. They have been found in fruit plantations, palm trees, or bushes, either in conical nests or burrows. Black rats in the modern era tend to inhabit the upper stories of wooden buildings, leading some to speculate that the observed decline in parts of Europe may have to do with the gradual disappearance of wooden buildings. But they are a hardy species, and now take refuge in sewers or cellars or even in trees in parts of Europe.

behavior

These mostly nocturnal rats have used their climbing skills to their advantage, by traveling along power lines and cables to spread from house to house. They are highly social creatures, which travel in packs, sleep in piles, and when they meet, they crawl beneath one another. They also can be territorial and display various postures similar to other animals in the genus, including the threat posture, a hunched, hair-bristled pose that aggressive individuals assume to display animosity.

feeding ecology and diet

Primarily vegetarians, feeding on fruit and seeds, but will eat insects and other invertebrates if necessary.

reproductive biology

Polygamous. Breed year-round in conducive habitats, producing up to five litters per year. The females, which have 12 nipples, give birth to litters consisting of between 6–12 young, with the average litter size being eight. Young open their eyes at 15 days of age.

conservation status

Not threatened.

significance to humans

Have been closely tied with humans for thousands of years, and are vermin-infested creatures responsible for spreading various diseases to humans, including the bubonic plague that swept Europe in the fourteenth century and various other eras. The rats harbor fleas, which, after biting the rat, can transfer the bacteria responsible for the plague to humans. Black rats, especially those in tropical climates, still spread the bubonic plague. The animals are known to strip the bark off of trees and they tend to infiltrate food caches and eat anything people have tried to store, including grains, seeds, cereals, and fruits. The main predator of the black rat is the house cat.

Tree rat

Thallomys paedulcus

taxonomy

Mus paedulcus (Sundevall, 1846), interior of Kaffirland, South Africa.

other common names

English: Acacia rat.

physical characteristics

Body length 4.7–6.4 in (12–16.3 cm); tail 5.1–8.2 in (13–21 cm); weight 2.2–3.5 oz (63–100 g). Has long fur that ranges from soft to coarse. Its coloring ranges from yellowish gray to gray to fawn on its upper parts, it has a brown tail, grayish or white feet and hands, red-tinted, nearly hairless ears, and a white belly. As a rule, tree rats have tails roughly 140% the length of their bodies. They have hind feet with strong claws and a well-developed fifth digit, which enables it to climb trees well.

distribution

Found in Africa, between western Somalia, southern Ethiopia, Angola, and South Africa.

habitat

Also known as the acacia rat, it makes its home in the acacia tree. It sometimes builds messy nests from twigs and grass in forks or in branches, and the nests are very obvious during winter, when the trees lose their leaves. On occasion, however, it will live in holes, beneath loose bark, and inside of hollow trunks. It uses the plant's thorns as protection from predators and can sometimes be found up to 13 ft (4 m) aboveground.

behavior

Shy animals, and will rarely leave their shelters. They are known to weather major storms in their nests, even during floods. Sometimes, however, they will be forced to make their

way back up the tree to home. Navigation is aided by scent markings, which they lay on branches. They are expert climbers and live in communities, usually in some sort of family arrangement, with a pair of adults and their offspring and other descendents.

feeding ecology and diet

Forage in their acacia trees, and are nocturnal. They eat acacia seeds and leaflets, but if necessary will eat insects and meat. They are able to survive without water.

reproductive biology

Does not breed during the African winter, from April–July, which coincides with the lack of water during that time. When the rainy season hits, the females will produce litters of 2–5 young, however, and can breed about every 3.5 months. Observed climbing trees with their young attached to their nipples.

conservation status

Not threatened.

significance to humans

An unsuitable lab rat because it does not breed well, and it is capable of spreading plague and other diseases. It is often infested with the stick tight flea (Echidnophaga gallinacea) as well as Xemonpsylla brasiliensis. It also harbors ticks and mites.

Brown rat

Rattus norvegicus

taxonomy

Rattus norvegicus (Berkenhout, 1769), Great Britain.

other common names

French: Rat d'égout, surmulot; German: Wanderratte; Spanish: Rata noruega.

physical characteristics

Body length 8.6–10.2 in (22–26 cm); tail 7–8.6 in (18–22cm); weigh 7–14 oz (200–400 g); can reach 1.1 lb (0.5 kg) on rare occasions. Different than the black rat, in that the brown rat grows larger, has a thicker build, shorter ears and tail, and coarser fur. It is reddish brown to grayish brown on the back and often has darker sides. Fur on its belly is a light slate.

distribution

Believed to have originated in the northern regions of Asia, perhaps in China or Mongolia, and spread westward. It reached Western Europe in 1716 via a ship docking in Copenhagen; hit France in 1735, and then the shores of America in 1755, it spread to England by 1750. Ships and ocean vessels have spread the rodents to nearly all of the world's seaports.

habitat

Lives just about anywhere, but it does not fare well in hotter climates. It is well adapted for the colder climes, and the species has actually inhabited a whaling station in Antarctica. It lives in close proximity to humans, often found anywhere from burrows and cavities to sewers and cellars. In homes, brown rats, which are poor climbers, are at ground level. Although the species is not aquatic, it can swim well and has been spotted in rivers or ocean waters.

behavior

Social animals that live and hunt in groups with close familial relationships, although they do allow non-related animals in on occasion. They can form groups as large as 200 animals usually with a dominant male overseeing the social order. Dominance hierarchies are determined by size and weight rather than age.

feeding ecology and diet

Eats a variety of things, although it prefers meat. It can swim, dive, and catch fish. In the 1940s, a pack of 15,000 brown rats decimated the bird population of a sanctuary on the island of Nooderoog, eating eggs and catching seagulls, ducks, passerines, and other species. They have also been known to eat mice, chickens, ducks, and geese, and will gnaw on lambs and piglets. Rat packs have ganged up to kill cats and dogs that have been deployed to keep their populations in check. They have been known to feed on elephants, invalids, and newborn babies. They have also been described as cannibalistic. It will take its catch back to its den for feasting, and can live without water as long as it consumes sufficiently moist food.

reproductive biology

They will breed throughout the year, although they peak in the spring and fall. When females go into heat, which lasts for six hours, a collection of males will mate with her. Each female will produce between 2–12 litters each year, with each litter consisting of 6–12—and as many as 22—young. The pups are born blind and pink, they open their eyes after about two weeks, and they leave the nest after three weeks. In a pack, the females give birth to their pups in the same room and assist each other in raising their young. The young are able to breed after 90 days. In optimal conditions, the animals are capable of producing up to 800 offspring per year, but this number is considerably lower in the wild.

conservation status

Not threatened.

significance to humans

Best known as carriers of the bubonic plague, and for centuries have eaten and contaminated human food. A descendent, the white albino lab rat, has proven invaluable to scientific research and discoveries in human health research.

Harvest mouse

Micromys minutus

taxonomy

Micromys minutus (Pallas, 1771), Ulyanovsk, Russia.

other common names

English: Old World harvest mouse; French: Souris des moissons; German: Eurasiatische zwergmaus; Spanish: Ratón espiguero.

physical characteristics

One of the smallest rodents: length 2.1–2.9 in (5.5–7.5 cm); tail 1.9–2.7 in (5–7 cm); weight 0.17–0.24 oz (5–7 g). Brownish color with lighter tint on top, its fur grows longer in the winter, and it has small ears, broad feet, and no hair on the top of the end of its tail, which is semi-prehensile. Its feet are adapted to a climbing lifestyle.

distribution

Generally found where there is high grass, specifically in northern Eurasia. It is also distributed throughout Siberia, Korea, China, Great Britain, Japan, and Taiwan.

habitat

Lives in high grass, in areas such as pastures, grain fields, and rice fields. It can also be found in bamboo thickets. The animal builds nests, suspended between grass stems, about 3.2 ft (1 m) aboveground. The nests, which can take two days to build, are made from woven leaves, with the inner layer being finely shredded to provide a soft spot for young. The animals also nest in holes or, in some circumstances, on the ground during winter. They may also move into human structures like barns to avoid the cold.

behavior

Nocturnal. The animals live in crowded conditions, but are not as social as black or brown rats. Captive males have been known to fight each other, and males and females only come together to build nests and to mate. Females chatter to attract mates and squeal during aggressive outbursts.

feeding ecology and diet

Forages in the grass fields primarily before dawn and just after dusk. It feeds on seeds and vegetables, but does on occasion take insects and eggs of small birds. Their unique climbing adaptations, like their semi-prehensile tail and their feet, allow them to climb through grass fields and counterbalance themselves as they move about.

reproductive biology

Polygamous. Females reproduce during the warmer months, from May–September, and they are capable of giving birth several times in succession. Gestation time is about 2.5 weeks. Each litter ranges from one to 13 pups, with an average of five. They are blind and naked at birth, but within 10 days can see and have fur. They are weaned at two weeks and start to reproduce at one month of age. They are capable of living to nearly five years in captivity, but rarely live longer than six months in the wild.

conservation status

Not threatened, but certain populations near farm machinery are in decline due to habitat loss.

significance to humans

No major significance.

Creek rat

Pelomys fallax

taxonomy

Pelomys fallax (Peters, 1852), Zambezi River, Mozambique.

other common names

English: Swamp rat, groove-toothed swamp rat.

physical characteristics

Body length 3.9–8.2 in (10–21 cm); tail 3.9–7 in (10–18 cm); weight 3.9–7 oz (100–170 g). The animal has rusty brown fur on top and a dirty white on bottom; the fur is rough, but not spiny. There is also a variable dorsal line that runs to the tail that is especially prominent in young animals. The tail is haired, with white below and black on top, and its length varies with populations. It has grooved upper incisors, which is unusual in the murines.

distribution

Distributed throughout southern Africa, in northern Mozambique, northwestern Zimbabwe, northern Botswana, Zambia, the Congo, Malawi, Tanzania, southwestern Uganda, and southern Kenya.

habitat

Inhabit streams, rivers, riverbanks, and swamps, or anywhere there is substantial amounts of water and vegetation. They can also live in grasslands, provided these areas border swamps or rivers.

behavior

Generally diurnal and aquatic, it is an excellent swimmer and is said to be difficult to trap. It is often found sunbathing on matted reeds and grasses.

feeding ecology and diet

Vegetarian, and it eats reeds, grasses, seeds, and other plants and plant material.

reproductive biology

Little is known, other than no predictable breeding season exists. The animals tend to reproduce in the warmer months, from August–April, and litter sizes ranger from 2–4 young. It is not determined if they live above or below ground: some believe they make shallow burrows, since their bodies have turned up in tilled fields, while others have surveyed habitat areas and have found no holes that could be burrows.

conservation status

Not threatened.

significance to humans

Not considered a pest and is eaten by tribes in Angola.

Egyptian spiny mouse

Acomys cahirinus

taxonomy

Mus cahirinus (Desmarest, 1819), Cairo, Egypt.

other common names

English: Spiny mouse; French: Rats épineux; German: Stachelmäuse; Spanish: Ratón espinoso.

physical characteristics

Body length 2.7–6.7 in (7–17 cm); tail 1.9–4.7 in (5–12 cm); weight 1–2.4 oz (30–70 g). The defining feature is the gray-brown to sandy spiny hairs covering its back. The large-eared animal has a gray to white belly and a scaly, hairless tail.

distribution

Distributed through Africa and the Middle East. The Egyptian spiny mouse is widely distributed, but it was first discovered in Egypt.

habitat

Live in arid and semi-arid environments like deserts and savannahs. They live in and around rocks and can be found in burrows, which they presumably do not dig themselves, and have been found in trees even though they are terrestrial. They tend to avoid altitudes above 4,920 ft (1,500 m), and in some places, particularly in Egypt, the animals live with and off of humans.

behavior

Different spiny mice species (there are eight) feed at different times and thus avoid competing with each other over the amount of insects they eat. Still, they are also known to be relatively social, and live in small groups with a dominant male who, when challenged, will fight. The animals are excellent jumpers and fairly active. Humans do keep them as pets.

feeding ecology and diet

Takes arthropods; certain species forage at different times in order to reduce interspecies competition. However, the animals also feed on snails as well as plant materials, including grains and grasses. Some species have begun to live in close proximity to humans, and are known to feed on grains and other foods that have been stored away.

reproductive biology

Build a rudimentary nest in which to give birth. The gestation period is 5–6 weeks, or about two weeks longer than the mouse norm, and small litters of 1–5 young are born. They are capable of breeding again almost immediately after birth, and they have been known to string together over 12 litters in succession. What sets the spiny mouse apart from other mice is that the young are well developed at birth. They are born with hair that, although thin, is enough to allow the pups to thermoregulate, which means the mother does not need to give them much body warmth. Further, their eyes are either open at birth or within a day or two of birth. By day three, the young are exploring. Due to the social nature of the creatures, females help each other during the birthing process. In function, all the females in a group help raise the young.

conservation status

Not threatened, although Acomys cilicicus is listed as Critically Endangered, while Acomys minous is Vulnerable.

significance to humans

Although the animals are known to spread typhus, they have recently received significant attention as a worthwhile pet. Apparently, people enjoy keeping the animals because their urine is relatively devoid of odor, and they are docile. The spiny mouse pet trade appeared in the mid 1980s.

Greater stick-nest rat

Leporillus conditor

taxonomy

Leporillus conditor (Stuart, 1848), New South Wales, Australia.

other common names

English: Stick nest rat, Australian stick nest rat, house-building rat, Franklin Island stick-nest rat, Franklin Island house-building rat; French: Léporilles; German: Zweignestratten.

physical characteristics

Body length 6.7–10.2 in (17–26 cm); tail 5.7–7 in (14.5–18 cm); weight (180–450 g). It has large eyes and large ears, which are round and dark. Its tail has hair, with longer bristles at the end. Covered in soft fur that is light gray or white below and yellowish brown or gray on top.

distribution

Originally distributed throughout southern Australia, from the Shark Bay vicinity to western New South Wales. It was also found in Franklin Island and northwestern Victoria. Currently, due to declining numbers, it is found naturally occurring only on the East and West Franklin Islands. Captive-bred individuals have been successfully reintroduced on other islands, as well as only a few fenced-in areas in the original distribution range.

habitat

Inhabit arid regions with little or no fresh water. They use regional twigs and shrubs to build enormous nests that can reach over a 3.2 ft (1 m) high.

behavior

The nocturnal rodents are sometimes known to build giant, towering nests called "wurlies" from sticks, twigs, and plant

stalks. They usually use a preexisting shrub, and sometimes, large rocks, to scaffold the nest; they proceed to weave sticks around the framing shrub. They occasionally incorporate stones into the nest, which serve to anchor it against winds, and they line the center with grasses. Up to 20 rats can live in the largest nests, which are filled with tunnels leading from the nest center to its outside. Younger generations inherit the nests and the task of tending to them. In fact, the nests have been shared with bandicoots, snakes, penguins, and shearwaters. Further, they are known to be docile and do not bite humans when handled. However, the social animals live in groups and display aggression towards unknown greater stick-nest rats.

feeding ecology and diet

Completely vegetarian, feeding on leaves and fruits and succulents for hydration.

reproductive biology

When conditions are optimal, the animals can breed anytime of the year. Gestation lasts for about six weeks, litters consist of only several young weaned after a few months, and they re-produce only two or three times annually, making their reproductive rates far less than more successful murine rodents like black rats.

conservation status

Recently upgraded from Endangered to Vulnerable due to recovery efforts; its relative, the lesser stick-nest rat, is assumed to be Extinct.

significance to humans

None, but theirs numbers have disappeared in part because of humans. Introduced animals like sheep have overgrazed and subsequently destroyed much of their preferred shrubland habitat. Scientists have been trying to repopulate various offshore Australian islands with the rats after having eradicated feral cats and other pests that could prey on the animals. Over the past few years, a successful breeding program in captivity has produced a large number of rats used to repopulate Australia, and the total greater stick-nest rat population has increased fivefold to over 5,000 individuals.

Australian jumping mouse

Notomys alexis

taxonomy

Notomys alexis (Thomas, 1922), Northern Territory, Australia.

other common names

English: Australian hopping mouse, jerboa mouse; French: Souris sauteuses d'Australie; German: Australische Hüpfmäuse; Spanish: Ratón saltador.

physical characteristics

Body length 3.9–5.9 in (10–15 cm); tail 3.5–8.2 in (9–21 cm); weight 0.7–1.7 oz (20–50 g). Their upper coloring is light sandy brown to gray. Their bellies are white to light gray. They have long tails and large ears, but their distinguishing feature is the narrow, large hind feet that enable them to effortlessly jump higher than 3.2 ft (1 m), and relatively small forefeet. Their tails are long and finely coated and, like the rest of the genus, have sebaceous glands, which are utilized for territorial marking.

distribution

Endemic to and spread throughout central Australia's deserts arid landscapes.

habitat

Live in dunes and grasslands and dig burrows that can vary in complexity.

behavior

Nocturnal social creatures, they involve themselves in grooming, huddling, walking over each other, crawling under each other, and sleeping together. When they fight, they not only rush at each other and punch each other with their fore legs, but they also leap at each other. The hopping mice generally walk on all fours, but in cases of haste and aggression will leap with their hind legs. They also live in groups with a high maximum density.

feeding ecology and diet

Eat berries and other vegetation, but they can live without water provided they receive sufficient hydration from their regular diet. They have extremely concentrated urine and avoid dehydration by staying underground during periods of intense heat.

reproductive biology

A month-long gestation period leads to a litter of about three pups. They are born naked and blind, but open their eyes by week three and are weaned after five weeks and are ready to reproduce at three months. Females carry their young by their nipples. Their reproductive rates vary widely, depending on ecological conditions.

conservation status

The dusky hopping mouse, N. fuscus, is listed as Vulnerable.

significance to humans

There is no major significance to humans, but they have become popular pets.

Resources

Books

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

Barnett, S. Anthony. The Story of Rats. Crows Nest, Australia: Allen & Unwin, 2001.

Corbett, G. B., and F. Hill. A World List of Mammalian Species. New York: Facts on File, 1986.

De Graff, G. "Creek Rats." In Rodents of Southern Africa. Woburn, MA: Durban, 1981.

——. "Tree Rats." In Rodents of Southern Africa. Woburn, MA: Durban, 1981.

Hanzak, J. Encyclopedia of Animals. New York: St. Martin's Press, 1965.

Nowak, R. M. Walker's Mammals of the World. 6th ed. Baltimore and London: Johns Hopkins University Press, 1999.

Periodicals

Flaming, P. A., and S. W. Nicolson. "Opportunistic Breeding in the Cape Spiny Mouse Acomys subspinosus." African Zoology 37, no. 1 (2002): 101–105.

Le Roux, V., J. L. Chapuis, Y. Frenot, and P. Veron. "Diet of the House Mouse (Mus musculus) on Guillou Island, Kerguelen Archipelago, Subantarctic." Polar Biology 25 (2002): 49–57.

Kronfeld-Schor, N., and T. Dayan. "The Dietary Basis for Temporal Partitioning: Food Habits of Coexisting Acomys Species." Oecologia 121, no. 1 (1999): 123–128.

Organizations

American Zoo and Aquarium Association Behavioral Advisory Group's ethograms.org. Web site: <http://www.ethograms.org>

The Department for Environment and Heritage of Southern Australia. GPO Box 1047, Adelaide, South Australia 5001 Australia. Phone: (8) 8204-9000. Web site: <http://www.environment.sa.gov.au/>

The Department of Conservation and Land Management for Western Australia. Hackett Drive, Crawley, Western Australia 6009 Australia. Phone: (8) 9442-0300. Fax: (8) 9386-1578. Web site: <http://www.calm.wa.gov.au/>

IUCN—The World Conservation Union. Rue Mauverney 28, Gland, 1196 Switzerland. Phone: +41 (22) 999 0000. Fax: +41 (22) 999 0002. E-mail: mail@hq.iucn.org Web site: <http://www.iucn.org>

The National Wildlife Federation. 1045 Sansome St., Suite 304, San Francisco, CA 94111 USA. Phone: (415) 732-7000. Fax: (415) 732-7007. Web site: <http://www.nwf.org/> and <http://www.enature.com>

Other

Rodentmania, The Rodent Dictionary. [June 2003] <http://members.tripod.com/Nager/index.htm>.

Animal Info: Rare, Threatened and Endangered Mammals. [June 2003] <http://www.animalinfo.org/>.

The Animal Diversity Web. [June 2003] <http://animaldiversity.ummz.umich.edu/>.

Smithsonian Institute, Murine Species List. [June 2003] <gopher://nmnhgoph.si.edu:70/0R144788-165041-/.docs/mammals_data/list>.

The House Mouse. [June 2003] <http://www.death-valley.us/article41.html>.

Molecular Systematics (for Rodents). [June 2003] <http://cgb.utmem.edu/faculty/Adkins/>.

Nathan S. Welton