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Rodents Temporal range: Early Paleocene – Present, 61.7–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Clockwise from top left: capybara (Hystricomorpha), springhare (Anomaluromorpha), Cape ground squirrel (Sciuromorpha), North American beaver (Castorimorpha) and wood mouse (Myomorpha)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Mirorder:	Simplicidentata
Order:	Rodentia Bowdich, 1821
Suborders
Anomaluromorpha Castorimorpha Hystricomorpha inc. Caviomorpha Myomorpha Sciuromorpha
Combined range of all rodent species

Rodents are mammals of the order Rodentia, characterised by a single pair of continuously growing incisors in each of the upper and lower jaws that must be kept short by gnawing.

About 40% of mammal species are rodents, and they are found in vast numbers on all continents other than Antarctica. Common rodents include mice, rats, squirrels, porcupines, beavers, guinea pigs, and hamsters. Rodents use their sharp incisors to gnaw food, excavate burrows and defend themselves. Most rodents eat seeds or plants, though some have more varied diets.

Rodents first appeared in the fossil record on the supercontinent of Laurasia in the Paleocene. They diversified in the Eocene, and different groups migrated repeatedly from continent to continent, sometimes by crossing oceans. Unlike most other placental mammals, one family of rodents, the Murinae (rats and mice), reached and colonized Australia. Some fossil species, such as the giant beavers, Castoroides, and a giant dormouse, Leithia, attained great size. The largest known rodent was Josephoartigasia monesi, a giant pacarana.

Rodents interact with humans in a variety of ways, and have been put to many human uses including as pets and as laboratory animals. Some species are serious pests, eating food stored by humans and spreading disease. Accidentally introduced rodents threaten the survival of many other species such as island birds previously isolated from rodents.

Characteristics

Rodents are generally small animals, most species weighing less than 100 g (3.5 oz). The largest species, the capybara, can weigh as much as 66 kg (146 lb). Rodents typically have squat bodies and short limbs. The fore-limbs usually have five digits, including a sometimes vestigial thumb, while the hind-limbs may have three to five digits. The elbow gives the fore-arms great flexibility. The majority of species are plantigrade, walking on both the palms and soles of their feet, and have claw-like nails. In general, rodents are not well adapted for running but a few species, like the agouti are fleet-footed, being digitigrade and having hoof-like nails. Kangaroo mice and jerboas can hop at 48 km/h (30 mph). Semi-aquatic species like the beaver have webbed feet. Squirrels have well-developed dexterity in their front paws. The majority of species have tails, which can be of many shapes and sizes. Some tails are even prehensile, as in the Eurasian harvest mouse. The pelage of the tails can vary from bushy to completely bald. Some species have vestigial tails or no tails at all. In some species, the tail is capable of regeneration if part is broken off.

Rodents generally have well developed senses of smell, hearing and vision. Nocturnal species often have enlarged eyes and some are sensitive to ultraviolet light. Many species have long, sensitive vibrissae for touch or the behavior of "whisking". Some rodents have cheek pouches some of which are lined with fur and the animal can turn them inside out for cleaning. In many species, the tongue cannot reach past the incisors. Rodents have very efficient digestive systems, absorbing nearly 80% of ingested energy. When eating cellulose, the food is softened in the stomach and passed to the fairly large cecum where bacteria reduce it to its digestive carbohydrate elements. The rodent then re-ingests the food from its anus so that the nutrients can be absorbed in the gut. The final result is a hard and dry fecal pellet. In males, the penis contains a bone (baculum) and the testes can be located either abdominally or at the groin.

Dentition and jaw musculature

The feature that most distinguishes rodents is their teeth, particularly their razor sharp incisors which have thick layers of enamel on the front and little enamel on the back. Because the incisors do not stop growing, the animal must continue to wear them down so that they don't grow far enough to reach or even pierce the skull. As the incisors grind against each other, the softer dentine on the rear of the teeth wears away, leaving the sharp enamel edge like the blade of a chisel. Most species have no more than 22 teeth (an exception being the silvery mole rat which has 28 teeth) with no canines or anterior premolars. There is a gap, or diastemata, between the incisors and the molars. This lets rodents suck in their cheeks or lips to shield their mouths and throats from wood shavings or other inedible material removed from whatever they are gnawing. The molars are relatively large, intricately structured and covered with convoluted ridges of enamel which are arranged transversely. They are well equipped to grind food into small particles.

The jaw musculature is strong. The lower jaw is thrust forward while gnawing but is pulled backwards during chewing. Rodents are capable of gnawing though even the toughest husks, pods and seed shells.

Rodents are divided into three groups according to the arrangement of the jaw muscles and associated skull structures. The Sciuromorpha (squirrel-like rodents) have a very simple jaw muscle that extends onto the snout in front of the eye. The Myomorpha (mouse-like or rat-like rodents) have jaw muscles that anchor on the side of the nose - these are the most efficient amongst the rodents. The Caviomorpha (cavy-like rodents) have very large cheekbones and muscles that anchor to the side of the face.

Distribution and habitat

Rodents are one of the most widespread group of mammals. They can be found on every continent expect Antarctica and, along with bats, are the only terrestrial placental mammals that have colonised Australia and New Guinea without human intervention. Humans have also allowed the animals to spread further into some oceanic islands. Rodents have adapted to almost every terrestrial habitat, from cold tundra (where they live under snow) to hot deserts. Some species are arboreal, while others live underground where they built complex burrow systems and others dwell on the surface. Beavers and muskrats are known for being semi-aquatic. Rodents have also thrived in human-created environments such as agricultural and urban areas.

Though some species are common pests for humans, rodents also play important ecological roles. Borruwing rodents may eat the fruiting bodies of fungi and dispose spores through their digestive tracts, allowing the fungi to form symbiotic relationships with the roots of plants (which usually can't survive without them). As such, these rodents may play a role in maintaining healthy forests.

Some rodents are considered keystone species and ecosystem engineers in their respective habitats. In the Great Plains of North America, the burrowing activities of prairie dogs play important roles in soil aeration, nutrient redistribution, organic matter levels and water infiltration. They maintain these grassland habitats and some large herbivores like bison and pronghorn prefer to graze near prairie dog colonies due to the increased nutritional quality of forage. Conversely, prairie dogs can also lead to regional and local biodiversity loss, increased seed depredation and the establishment and spread of invasive shrubs. When building their dams and lounges, beavers alter the paths of streams and rivers and allow for the creation of extensive wetland habitats. One study found that engineering by beavers leads to a 33 percent increase in the number of herbaceous plant species in riparian areas. Another study found that beavers increase wild salmon populations.

Behavior

Feeding

Most rodents feed exclusively on plant material, including seeds, stems, leaves, flowers and roots, but some are omnivorous and others are carnivores. The field vole is a fairly typical herbivorous rodent and feeds on grasses, herbs, root tubers, moss and other vegetation, and gnaws on bark during the winter. It occasionally eats invertebrates such as insect larvae. The plains pocket gopher eats plant material that it finds during its tunnel excavations underground, and also collects grasses, roots and tubers in its cheek pouches and caches them in underground larder chambers. The Texas pocket gopher avoids emerging onto the surface by seizing the roots of plants with its jaws and pulling them downwards into its burrow. It also practices coprophagy, eating its own fecal pellets. The African pouched rat hurries around on the surface, gathering anything that might be edible in its capacious cheek pouches till its face bulges out sideways. It then returns to its burrow to sort through its finds and eats the nutritious items at leisure.

The agouti is one of very few animals that can break open the large capsules of the Brazil nut fruit. There are too many seeds inside to be consumed at one time so the agouti carries some off and buries them for later use. This serves in the dispersal of the seeds as any that the animal fails to retrieve are far away from the shade of the parent tree when they germinate. Other nut-bearing trees tend to bear a glut of fruits in the autumn. These are too numerous to all be eaten and squirrels gather and store the surplus in crevices and hollow trees. In desert regions, seeds are often only available for short periods. The kangaroo rat collects all it can find and stores them in larder chambers in its burrow.

A strategy for dealing with seasonal plenty is to eat as much as possible and store the surplus nutrients as fat. Marmots do this, and may be 50% heavier in the fall than they were in the spring. They rely on their fat reserves during their long winter hibernation in the snow-clad mountains where they live. Their bodily activities slow down and they huddle together, maintaining their body temperatures at about 5 °C (41 °F). Beavers feed on the leaves, buds and inner bark of growing trees, as well as various aquatic plants. They store food for winter use by felling small trees and leafy branches in the fall and immersing them in their pond, sticking the end into the mud to anchor them. Here they can access their food supply underwater even when their pond is frozen over.

One of the few carnivorous rodents is the grasshopper mouse of dry regions of North America which feeds on insects, scorpions, other small mice and a small proportion of plant material. It has a chunky body with short legs and tail, but is agile and easily able to overpower prey as large as itself. Another is the Australian water rat which feeds on crustaceans, insects, small fish, frogs and mollusks. Some plant matter is also eaten, especially in the winter.

Social behavior

Rodents exhibit a wide range of types of social behavior ranging from the only known mammalian caste systems of some mole rats, the extensive "town" of the colonial prairie dog, through family groups to the independent, solitary life of the edible dormouse.

In the case of the dormouse, males and females live independently, only coming together briefly in the breeding season to mate. Their feeding ranges may overlap but they live in individual nests and feed separately. The female raises the young without any assistance from the male. The pocket gopher is also a solitary animal outside the breeding season, each individual digging a complex tunnel system and maintaining a territory.

Larger rodents tend to live in family units where parents and their offspring live together until such time as the youngsters disperse. Beavers live in extended family units typically with a pair of adults, this year's kits, the previous year's offspring and sometimes older young.

Brown rats usually live in small colonies with up to six females sharing a burrow and one male defending a territory around the burrow. At high population densities, this system breaks down and males show a hierarchial system of dominance with overlapping ranges. Female offspring remain in the colony while male young disperse.

The prairie vole is monogamous and forms a life-long pair bond. Outside the breeding season, prairie voles live in close proximity with others in small colonies. A male is not aggressive towards other males until he has mated, after which time he defends a territory, a female and a nest against other males. The pair huddle together, groom one another, and share nesting and pup-raising responsibilities.

Among the most social of rodents are the ground squirrels, which typically form colonies based on female kinship, males dispersing after weaning and becoming nomadic as adults. Co-operation in ground squirrels varies between species and typically includes making alarm calls, defending territories, sharing food, protecting nesting areas and preventing infanticide. The black-tailed prairie dog forms large towns that may cover many hectares. The burrows do not interconnect but are excavated and occupied by territorial family groups known as coteries. A coterie often consists of an adult male, three or four adult females, several non-breeding yearlings and this year's offspring. Individuals within coteries are friendly with each other, but hostile towards outsiders.

Perhaps the most extreme examples of colonial behavior in rodents are the eusocial naked mole rat(Heterocephalus glaber) and Damaraland mole rat (Fukomys damarensis). These are considered to be the only two eusocial mammals. The naked mole rat lives completely underground and can form colonies of up to eighty individuals. Only one female and up to three males in the colony reproduce, while the rest of the members are smaller, sterile and function as workers. Some individuals are of intermediate size, help with the rearing of the young and can take the place of a reproductive if one of these dies. The Damaraland mole rat is characterized by having a single reproductively active male and female in a colony where the remaining animals are not truly sterile, but only become fertile if they establish a colony of their own.

Communication

Many rodent species, particularly those that are diurnal and social, have a wide range of alarm calls that are emitted when they perceive threats. There are both direct and indirect benefits of doing this. A potential predator may desist when it knows it has been detected, or, an alarm call can allow conspecifics or relaed individuals to take evasive action. Several species, for example prairie dogs, have complex anti-predator alarm call systems. These species may have different calls for different predators (e.g. aerial predators or ground-based predators) and each call contains information about the nature of the precise threat. The urgency of the threat is also conveyed by the acoustic properties of the call.

Social rodents living underground have a wider range of vocalizations than do solitary species. Fifteen different call-types have been recognised in adult Kataba mole rats and four in juveniles. Similarly, Degus, another social, burrowing rodent, exhibit a wide array of communication modalities and have an elaborate vocal repertoire comprising fifteen different categories of sound. Ultrasonic calls play a part in social communication between dormice and are used when the individuals are out of sight of each other.

Rats emit short, high frequency, ultrasonic, vocalizations during purportedly pleasurable experiences such as rough-and-tumble play, before receiving morphine, during mating, and when tickled. The vocalization, described as a distinct "chirping", has been likened to laughter, and is interpreted as an expectation of something rewarding. In clinical studies, the chirping is associated with positive emotional feelings, and social bonding occurs with the tickler, resulting in the rats becoming conditioned to seek the tickling. However, as the rats age, the tendency to chirp declines. Like most rat vocalizations, the chirping is at frequencies that are too high for humans to hear without special equipment. Bat detectors are often used by pet owners for this purpose.

Using olfaction, rodents are able to recognise close relatives. This allows them to express nepotism (preferential behavior toward their kin) and also avoid inbreeding. This kin recognition is by olfactory cues from urine, faeces and glandular secretions. The main assessment may involve the major histocompatibility complex (MHC), where the degree of relatedness of two individuals is correlated to the MHC genes they have in common. In non-kin communication where more permanent odor markers are required, as at territorial borders, then non-volatile major urinary proteins (MUPs), which function as pheromone transporters, may be additionally used. MUPs may also signal individual identity, with each male house mouse excreting urine containing about a dozen genetically encoded MUPs.

Vibrations can provide cues to conspecifics about specific behaviors being performed, predator warning and avoidance, herd or group maintenance, and courtship. The Middle East blind mole rat (Spalax ehrenbergi) was the first mammal for which vibrational communication was documented. These fossorial rodents bang their head against the walls of their tunnels, which was initially interpreted as part of their tunnel building behavior, however, it was eventually realised they generate temporally patterned vibrational signals for long-distance communication with neighbouring mole rats. Footdrumming is used widely as a predator warning or defensive action. It is used primarily by fossorial or semi-fossorial rodents. The banner-tailed kangaroo rat (Dipodomys spectabilis) produces several complex footdrumming patterns in a number of different contexts, one of which is when it encounters a snake. The footdrumming may alert nearby offspring but most likely conveys that the rat is too alert for a successful attack, thus preventing the snake's predatory pursuit. Several studies have indicated intentional use of ground vibrations as a means of intra-specific communication during courtship among the Cape mole rat (Georychus capensis). Footdrumming has been reported to be involved in male-male competition where the dominant male indicates its resource holding potential by drumming, thus minimising physical contact with potential rivals.

Classification and evolution

Evolutionary history

The fossil record of rodent-like mammals begins shortly after the extinction of the non-avian dinosaurs 66 million years ago, in Laurasia, the supercontinent composed of today's North America, Europe, and Asia, during the Paleocene. Some molecular clock data, however, suggest modern rodents (members of the order Rodentia) had appeared in the late Cretaceous, although other molecular divergence estimations are in agreement with the fossil record.

The history of the colonization of the world's continents by rodents is complex. The movements of the large Muroidea superfamily (including hamsters, gerbils, true mice and rats) may have involved up to seven colonizations of Africa, five colonizations of North America, four of Southeast Asia, two of South America and up to ten re-colonizations of Eurasia.

During the Eocene, rodents began to diversify; for example beavers appear in North America in the late Eocene before spreading to Eurasia. By 20 million years ago (in the Miocene) fossils recognizably belonging to the current families such as Muridae appear. Late in the Eocene, hystricognaths colonized Africa, most probably having originated in Asia, at least 39.5 million years ago. From Africa, fossil evidence shows that some hystricognaths (caviomorphs) migrated to South America, which had been an isolated continent during the Oligocene and Miocene epochs, possibly making use of ocean currents and the Ceara and Sierra Leone Rises in the Atlantic. Caviomorphs had arrived in South America by 41 million years ago (implying a date at least as early as this for hystricognaths in Africa). By the Miocene, when Africa had collided with Asia, rodents such as porcupines began to spread into Eurasia.

During the Pliocene, rodent fossils appeared in Australia. Although marsupials are the most prominent mammals in Australia, many rodents, all belonging to the Murinae, are among the continent's mammal species, with about 50 'old endemics' and ten true rats (Rattus) of which eight are 'new endemics' and two were introduced by Europeans. Meanwhile, the Americas became joined by the Isthmus of Panama, and some rodents participated in the resulting Great American Interchange; sigmodontines surged southward and a small number of species such as New World porcupines (Erethizontidae) headed north.

Standard classification

The phylogeny of the rodents places them in the clades Glires, Euarchontoglires and Boreoeutheria:

The order Rodentia may be divided into suborders, infraorders, superfamilies and families.

Classification scheme:

Order Rodentia (from Latin, rodere, to gnaw)

• Suborder Anomaluromorpha

  • Family Anomaluridae: scaly-tailed squirrels
  • Family Pedetidae: springhares

• Suborder Castorimorpha

  • Superfamily Castoroidea
    • Family Castoridae: beavers
  • Superfamily Geomyoidea
    • Family Geomyidae: pocket gophers (true gophers)
    • Family Heteromyidae: kangaroo rats and kangaroo mice

• Suborder Hystricomorpha

  • Family incertae sedis Diatomyidae: Laotian rock rat

  • Infraorder Ctenodactylomorphi

    • Family Ctenodactylidae: gundis

  • Infraorder Hystricognathi

    • Family Bathyergidae: African mole rats
    • Family Hystricidae: Old World porcupines
    • Family Petromuridae: dassie rat
    • Family Thryonomyidae: cane rats

    • Parvorder Caviomorpha
      • Family †Heptaxodontidae: giant hutias
      • Family Abrocomidae: chinchilla rats
      • Family Capromyidae: hutias
      • Family Caviidae: cavies, including Guinea pigs and the capybara
      • Family Chinchillidae: chinchillas and viscachas
      • Family Ctenomyidae: tuco-tucos
      • Family Dasyproctidae: agoutis
      • Family Cuniculidae: pacas
      • Family Dinomyidae: pacaranas
      • Family Echimyidae: spiny rats
      • Family Erethizontidae: New World porcupines
      • Family Myocastoridae: nutria, coypu
      • Family Octodontidae: octodonts
• Suborder Myomorpha

  • Superfamily Dipodoidea
    • Family Dipodidae: jerboas and jumping mice
  • Superfamily Muroidea
    • Family Calomyscidae: mouse-like hamsters
    • Family Cricetidae: hamsters, New World rats and mice, muskrats, voles
    • Family Muridae: true mice and rats, gerbils, spiny mice, crested rat
    • Family Nesomyidae: climbing mice, rock mice, white-tailed rat, Malagasy rats and mice
    • Family Platacanthomyidae: spiny dormice
    • Family Spalacidae: mole rats, bamboo rats, and zokors

• Suborder Sciuromorpha

  • Family Aplodontiidae: mountain beaver
  • Family Gliridae (also Myoxidae, Muscardinidae): dormice
  • Family Sciuridae: squirrels, including chipmunks, prairie dogs, and marmots

Alternative classifications

The above taxonomy uses the shape of the lower jaw (sciurognath or hystricognath) as the primary character. This is the most commonly used approach for dividing the order into suborders. Many older references emphasize the zygomasseteric system (suborders Protrogomorpha, Sciuromorpha, Hystricomorpha, and Myomorpha).

Several molecular phylogenetic studies have used gene sequences to determine the relationships among rodents, but these studies have yet to produce a single, consistent and well-supported taxonomy. Some clades have been consistently produced, such as:

• Ctenohystrica contains:
  • Ctenodactylidae (gundis)
  • Hystricognathi containing:
    • Hystricidae
    • An unnamed clade containing:
      • Phiomorpha
      • Caviomorpha

• An unnamed clade containing:
  • Gliridae
  • Sciuroidea containing:
    • Aplodontiidae
    • Sciuridae

• Myodonta includes:
  • Dipodoidea
  • Muroidea

The positions of the Castoridae, Geomyoidea, Anomaluridae, and Pedetidae are still being debated.

Monophyly versus polyphyly

In 1991, a paper published by Nature proposed that caviomorphs should be reclassified as a separate order (similar to Lagomorpha), based on an analysis of the amino acid sequences of Guinea pig proteins. This hypothesis was refined in a 1992 paper, which asserted the possibility that caviomorphs may have diverged from myomorphs prior to later divergences of Myomorpha; this would mean caviomorphs, or possibly hystricomorphs, would be moved out of the rodent classification into a separate order. A minority scientific opinion argued that guinea pigs, degus, and other caviomorphs are not rodents, while several papers were put forward in support of rodent monophyly. Subsequent studies published since 2002, using wider taxon and gene samples, have restored a majority opinion among mammalian biologists that the order Rodentia is monophyletic, although there is not a complete consensus.

Interaction with humans

Conservation

While rodents are not the most seriously threatened order of mammals, there are 168 species in 126 genera which "deserve conservation attention" in the face of limited appreciation by the public. Since 76 percent of rodent genera contain only one species, much phylogenetic diversity could be lost with a comparatively small number of extinctions. In the absence of more detailed knowledge of species at risk and accurate taxonomy, conservation must be based mainly on higher taxa (such as families rather than species) and geographical hot spots. For example, in Colombia, the brown hairy dwarf porcupine, Sphiggurus vestitus was recorded from only two mountain localities in the 1920s, while the red crested soft-furred spiny rat, Santamartamys rufodorsalis, is known only from its type locality on the Caribbean coast, so these species are considered vulnerable. The IUCN Species Survival Commission writes "We can safely conclude that many South American rodents are seriously threatened, mainly by environmental disturbance and intensive hunting".

The "three now cosmopolitan commensal rodent pest species" (the brown rat, the black rat and the house mouse) have been dispersed in association with humans, partly on sailing ships in the Age of Exploration, and with a fourth species in the Pacific, Rattus exulans, have severely damaged island biotas around the world. For example, when the black rat reached Lord Howe Island in 1918, over 40 percent of the terrestrial bird species of the island became extinct within ten years. Similar destruction has been seen on Midway Island (1943) and Big South Cape Island (1962). Conservation projects can with careful planning completely eradicate these pest rodents from islands using an anticoagulant rodenticide such as brodifacoum. This approach has been successful on the island of Lundy in the United Kingdom where the eradication of an estimated 40,000 rats is giving populations of Manx shearwater and Atlantic puffin a chance to recover from near extinction.

Uses

As clothing

Humans use rodents as a source of fur, for example, the beaver.

As food

At least 89 species of rodent, mostly Hystricomorpha such as guinea pigs, agoutis and capybaras, are eaten by humans; guinea pigs were first raised for food around 2500 B.C. and by 1500 B.C. had become the main source of meat for the Inca Empire. Guinea pigs are used in the cuisine of Cuzco, Peru in dishes such as cuy al horno, baked guinea pig. In addition, the traditional Andean stove, known as a qoncha or a fogón, is made from mud and clay reinforced with straw and hair from animals such as guinea pigs.

As pets

Rodents kept as pets include guinea pigs, mice, rats, gerbils, chinchillas, degus and chipmunks.

As research models

Rodents are used widely as model organisms in animal testing. The naked mole rat, Heterocephalus glaber, is the only known mammal that is poikilothermic and also does not produce the neurotransmitter substance P; it is used in studies on thermoregulation and pain. The house mouse, Mus musculus, is the animal most commonly used in genetic engineering.

As olfactory detectors

Rodents have a sensitive olfactory sense which has been utilsed by humans to detect odours or chemicals of interest. The Gambian pouched rat is able to detect tuberculosis bacilli with a sensitivity of up to 86.6 %, and specificity (detecting the absence of the bacilli) of over 93 %; the same species has been trained to detect land mines.

As pests and disease vectors

Some rodent species are agricultural pests, eating large quantities of food stored by humans. For example, in 2003, the amount of rice lost to mice and rats in Asia was estimated to be enough to feed 200 million people.

Rodents are also vectors of disease. The black rat, Rattus rattus, with the fleas that it carries, plays a primary role in spreading the bacterium Yersinia pestis responsible for bubonic plague, and also carries the organisms responsible for typhus, Weil's disease, toxoplasmosis and trichinosis.

Because rodents are both a nuisance and endanger public health, human societies often attempt to control them. Traditionally this involved poisoning and trapping, methods which were not always safe and not always effective. More recently, integrated pest management attempts to improve control with a combination of surveys to determine the size and distribution of the pest population, the establishment of tolerance limits (levels of pest activity at which to intervene), interventions, and evaluation of effectiveness based on repeated surveys. Interventions may include education, making and applying laws and regulations, modifying the habitat, changing farming practices, biological control using pathogens or predators, as well as poisoning and trapping. The use of pathogens such as Salmonella has the drawback that they can infect man and domestic animals, while rodents often become resistant. The use of predators including ferrets, mongooses and monitor lizards has been found unsatisfactory. Domestic and feral cats are able to control rodents effectively provided the rodent population is not too large.

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Further reading

• Carleton, M. D.; Musser, G. G. "Order Rodentia", pages 745–752 in Wilson & Reeder (2005).
• McKenna, Malcolm C.; Bell, Susan K. (1997). Classification of Mammals Above the Species Level. Columbia University Press. ISBN 0-231-11013-8.{{cite book}}: CS1 maint: multiple names: authors list (link)
• Nowak, R. M. (1999). Walker's Mammals of the World, Volume 2. Johns Hopkins University Press. ISBN 978-0-80183-970-2.
• Wilson, D. E.; Reeder, D. M., ed. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference. Johns Hopkins University Press. ISBN 978-0-80188-221-0.{{cite book}}: CS1 maint: multiple names: editors list (link)

External links

Zoology, osteology, comparative anatomy

• UCMP Berkeley: Introduction to the Rodentia
• ArchéoZooThèque : Rodent osteology (photos)
• ArchéoZooThèque : Rodent skeleton drawings

Various

• African rodentia
• Rodent photos
• Rodent Pests chapter in EPA and University of Florida/IFAS manual

Template:Link FA Template:Link FA

• Rodents
• Animal orders