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Rattus rattus

(Black Rat)

Overview

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Mammal. A native of the Indian sub-continent, this rat has now spread throughout the world. It will feed on and damage almost any edible thing. Ship rats are widespread in forest and woodlands as well as being able to live in and around buildings. A very agile rat, it often frequents the tree tops searching for food and nesting there in bunches of leaves and twigs .

Common Names

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Click on the language to view common names.

Common Names in English:

Black Rat, House Rat, Roof Rat

Common Names in French:

Rat Noir

Description

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Physical Description

Species Rattus rattus

A slender rat with large hairless ears, it may be grey-brown on the back with either a similarly coloured or creamish-white belly, or it may be black all over. The uniformly-coloured tail is always longer than the head and body length combined. Its body weight is usually between 120 and 160 g but it can exceed 200 g.The work of Yosida (1980) and his co-workers has shown that there are two forms of R. rattus that differ in chromosome number. The more widespread Oceanic form has 38 chromosomes and is the ship rat of Europe, the Mediterranean region, America, Australia and New Zealand. Present indications are that it is the Oceanic form that has reached islands in the South Pacific, but studies are needed to confirm this. The Asian form has probably reached some islands north of the equator, e.g. the Caroline Islands. On the basis of colour variation in rats on Ponape and Koror Islands, described by Johnson (1962) as Rattus rattus mansorius, we suspect that these rats may be the Asian form of R. rattus (Source: SPREP).

Habitat

Ship rats can be widespread, utilising most habitat types , but they show a preference for drier habitats. They generally avoid swimming.

Typically found at an altitude of 0 to 5,469 meters (0 to 17,943 feet).[1]

Biome: agricultural areas, coastland, disturbed areas, natural forest , planted forests, range/grasslands, riparian zones, scrub/shrublands, urban areas

Ecology: Rattus rattus has directly caused or contributed to the extinction of many species of wildlife including birds, small mammals, reptiles , invertebrates , and plants , especially on islands. Ship rats are omnivorous and capable of eating a wide range of plant and animal foods. These include native snails, beetles, spiders, moths, stick insects and cicadas and the fruit of many different plants (Innes 1990). They also prey on the eggs and young of forest birds (Innes et al. 1999). In the recovery programme for the endangered Rarotonga flycatcher or kakerori (Pomarea dimidiata), Robertson et al. (1994) identified ship rats as the most important predator affecting the breeding success of this bird. Several cases are known where predation on seabirds can be reliably attributed to ship rats. These include sooty terns in the Seychelles Islands (Feare 1979), Bonin petrels in Hawaii (Grant et al. 1981), Galapagos dark-rumped petrels in the Galapagos Islands (Harris 1970), and white-tailed tropicbirds in Bermuda (Gross 1912). The ship rat is the rat most frequently identified with catastrophic declines of birds on islands. The best documented examples in the Pacific region are Midway Island in the Leeward Islands of Hawaii (Johnson 1945, Fisher and Baldwin 1946), Lord Howe Island (Hindwood 1940, Recher and Clark 1974) and Big South Cape Island, New Zealand (Atkinson and Bell 1973). Atkinson (1977) brought together circumstantial evidence suggesting that ship rats, rather than disease, were responsible for the decline of many species of Hawaiian native birds during the 19th century. There are few indications of rat-induced declines in native birds on islands nearer the equator (latitude 15°N to 20°S). This zone coincides with the distribution of native land crabs, animals that also prey on birds and their eggs. The long co-existence between land crabs and some island birds may have resulted in the development of behaviours among the birds that gives them a degree of protection against rats. Atkinson (1985) suggested that this might be the reason why rat-induced catastrophes are less apparent within the equatorial zone, but this hypothesis has never been tested. (Source: SPREP)

Biology

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Reproduction

A placental mammal with dependent young.Litter size 3-10 (average 5-8), with frequency of litters dependent on season and food supply. The interval between litters may be as little as 27 days.

Gestation 20-22 days. Weaning 21-28 days. Sexual maturity 3-4 months. Total life may not exceed two years.

Taxonomy

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Notes

Name Status: Accepted Name . Latest taxonomic scrutiny: 05-Feb-2001

Similar Species

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Members of the genus Rattus

There are approximately 158 species in this genus. Here are just 100 of them:

R. adustus (Sunburned Rat) · R. alexandrinus · R. annandalei (Annandale's Rat) · R. argentiventer (Rice-Field Rat) · R. argentiventer argentiventer (Rice-Field Rat) · R. baluensis (Summit Rat) · R. blanfordi · R. bontanus (Bonthain Rat) · R. bowersi · R. burrus (Nonsense Rat) · R. canus · R. colletti (Dusky Rat) · R. coucha · R. coucha silaceus · R. coxinga · R. cutchicus rajput · R. doboensis · R. edwardsi · R. eha · R. elaphinus (Sula Rat) · R. enganus (Enggano Rat) · R. everetti (Philippine Forest Rat) · R. exulans (Polynesian Rat) · R. exulans aitape · R. exulans concolor · R. exulans hawaiiensis · R. feliceus (Spiny Ceram Rat) · R. flavipectus · R. foramineus (Hole Rat) · R. fulvescens · R. fuscipes (Bush Rat) · R. fuscipes assimilis · R. fuscipes coracius · R. fuscipes fuscipes (Bush Rat) · R. fuscipes greyi · R. fuscipes greyii · R. giluwensis (Giluwe Rat) · R. hainaldi (Hainald's Rat) · R. hawaiiensis · R. hoffmanni (Hoffmann's Sulawesi Rat) · R. hoogerwerfi (Hoogerwerf's Rat) · R. hoxaensis · R. jobiensis (Japen Rat) · R. koopmani (Koopman's Rat) · R. koratensis · R. korinchi (Korinch's Rat) · R. legata · R. leucopus (Mottle-Tailed Rat) · R. leucopus cooktownensis · R. leucopus leucopus (Mottle-Tailed Rat) · R. losea (Lesser Rice-Field Rat) · R. losea losea (Lesser Rice-Field Rat) · R. lugens (Mentawai Rat) · R. lutreolus (Australian Swamp Rat) · R. lutreolus cambricus · R. lutreolus lacus · R. lutreolus lutreolus · R. lutreolus velutinus · R. macleari (Christmas Island Rat) · R. marmosurus (Opossum Rat) · R. meltada · R. mindorensis (Mindoro Black Rat) · R. mollicomulus (Little Soft-Furred Rat) · R. montanus (Nillu Rat) · R. mordax (Eastern Rat) · R. morotaiensis (Molaccan Prehensile-Tailed Rat) · R. muelleri · R. namaquensis · R. natalensis · R. nativitatis (Christmas Island Rat) · R. niobe · R. nitidus (Himalayan Field Rat) · R. nitidus nitidus · R. nitidus obsoletus · R. niviventer · R. norvegicus (Norway Rat) · R. norvegicus albinicus (Norway Rat) · R. norvegicus albino · R. norvegicus caraco · R. norvegicus domestica · R. norvegicus norvegicus (Norway Rat) · R. norvegicus socer · R. norvegicus var. albus (Norway Rat) · R. norvergicus · R. norvergicus albinus · R. novaeguineae (Papua New Guinea Rat) · R. osgoodi (Osgood's Rat) · R. owiensis · R. palmarum (Palm Rat) · R. pelurus (Peleng Rat) · R. praetor (Variable Spiny Rat) · R. ranjiniae (Kerala Rat) · R. rattoides · R. rattus (Black Rat) · R. rattus alexadrinus · R. rattus alexandrinus (Black Rat) · R. rattus andamanensis · R. rattus arboreus · R. rattus argentiventer (Rice-Field Rat) · R. rattus brunneus

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 12, 2007:

Identifiers

Footnotes

  1. Mean = 245.880 meters (806.693 feet), Standard Deviation = 458.860 based on 1,256 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 2009-04-24