Rattus norvegicus (Berkenhout 1769)

[Mus] norvegicus Berkenhout 1769, Outlines of the Natural History of Great Britain and Ireland, Vol. 1: 5.

Type Locality: Great Britain.

Vernacular Names: Brown Rat.

Synonyms: Rattus aquaticus (Rutty 1772); Rattus albinus (Donaldson 1912); Rattus albus Hatai 1907; Rattus americanus (de Kay 1842); Rattus caraco (Pallas 1778); Rattus caspius (Oken 1816); Rattus cauquenensis (Philippi 1900); Rattus decaryi (Grandidier 1934); Rattus decumanoides (Hodgson 1841); Rattus decumanus (Pallas 1779); Rattus discolor (Noack 1918); Rattus fossilis (Ameghino 1889); Rattus fossor (Walker 1808); Rattus griseipectus (Milne-Edwards 1872); Rattus hibernicus (Thompson 1837); Rattus hoffmanni (Trouessart 1904); Rattus humiliatus (Milne-Edwards 1868); Rattus hybridus (Bechstein 1800); Rattus insolatus Howell 1927; Rattus javanus (Hermann 1804); Rattus kurodobu Kuroda 1953; Rattus leucosternum (Rüppell 1842); Rattus lutescens (Gay 1848); Rattus magnirostris (Mearns 1905); Rattus major (Hoffmann 1887); Rattus maniculatus (Wagner 1848); Rattus maurus (Waterhouse 1839); Rattus migrans (Zimmermann 1777); Rattus orii Kuroda 1952; Rattus otomoi Yamada 1930; Rattus ouangthomae (Milne-Edwards 1871); Rattus plumbeus (Milne-Edwards 1874); Rattus praestans (Trouessart 1904); Rattus primarius Kastschenko 1912; Rattus shirokuma Kuroda 1953; Rattus simpsoni (Philippi 1900); Rattus socer Miller 1914; Rattus sowerbyi Howell 1928; Rattus suffureoventris Kuroda 1952; Rattus surmulottus (Severinus 1779); Rattus tamarensis (Higgins and Petterd 1883) .

Distribution: Original distribution assumed to be SE Siberia, N China (Heilongjiang), and Hondo region (islands of Honshu, Shikoku, and Kyushu; see Dobson, 1994) of Japan (Jones and Johnson, 1965; Kowalski and Hasegawa, 1976; Kawamura, 1989), but introduced worldwide where it is more common in colder climates of higher N and S latitudes (Kucheruk, 1990); in warmer regions and tropics restricted to habitats highly modified by humans (e. g., sewers, buildings, wharves, breakwaters, ports, and large cities; Johnson, 1962 a, Corbet and Hill, 1992). Considered extinct in Norway (Syvertsen et al., 1996).

Conservation: IUCN – Lower Risk (lc).

Discussion: Rattus norvegicus species group. Latitudinal geographic variation among Chinese populations reported by Wu (1982). Samples from native Asian, free-living introduced, and laboratory populations have been the subject of numerous morphological (e.g., Bugge, 1970; Cheng and Yen, 1993; Greene, 1935; Kiliaridis et al., 1996; Kimura et al., 1994, 1996; Millien-Parra, 2000 a; Naftel et al., 1999; Piette and Lametschwandtner, 1995; Puzachenko and Lapshov, 1994; Sakamoto, 1996), physiological, chromosomal and molecular (many are summarized in Yosida, 1980, and Levan et al., 1990; see also Behboudi et al., 2002; Belcheva et al., 1992; Koh et al., 1995; Robinson, 1984; Rothenburg et al., 2002) studies, which have produced among the mass of data a gene map of R. norvegicus (Levan et al., 1990) . Results of attempted hybridizations between R. norvegicus and different forms of R. rattus summarized by Yosida (1980). Assessment and review of swimming capability in context of potential to colonize tropical oceanic islands provided by Spennemann and Rapp (1980). Monographic treatment edited by Sokolov and Karasjova (1990) covers systematics, geographic distribution, ecology, behavior, and practical importance generally worldwide but with a focus on populations in Russia. Overall review of systematics reported by Schwarz and Schwarz (1967) and Miljutin (1990), who also included R. norvegicus in treatises covering ecomorphology and ecological strategies of Baltic rodents (Miljutin, 1997, 1998). Phylogenetic relationships to other members of subgenus Rattus equivocal (e.g., contrast Chan et al., 1979, with Pasteur et al., 1982), but morphological, isozymic, and molecular data indicate significant phylogenetic divergence between R. norvegicus and R. rattus (Baverstock et al., 1983 a, b, 1986; Chan, 1977; Verneau et al., 1997, 1998). Phallic morphology of Chinese samples described by Yang and Fang (1988) in context of assessing phylogenetic relationships among Chinese murines. Significance of the ecological distributions between R. norvegicus and R. rattus in the Caucasus investigated by Kalinin (1993), and in the Galápagos Isls by Key and Woods (1996). Contrasts in surface topography of hind foot plantar pads between R. norvegicus, R. argentiventer, R. rattus, and R. exulans documented by Yabe et al. (1998); the first two are primarily terrestrial and have low and inconspicuous lamellae on the pads, but the last two are terrestrial and arboreal and their pads are adorned with well developed lamellae.

European populations reviewed Becker (1978 b) and Mitchell-Jones et al. (1999); range, taxonomy, and other characteristics of species in Russia and adjacent regions summarized by Gromov and Erbajeva (1995); taxonomy and distribution in Indomalayan region presented by Corbet and Hill (1992); North American taxonomy and range outlined by Hall (1981); Chilean by Osgood (1943); and Australian populations, which are restricted to major coastal cities and ports, reviewed by Mahoney and Richardson (1988) and Watts (1995 i). Summaries of geographic distribution, habitat, ecology, interaction with other mammalian species as well as humans, and sometimes history of colonization, are available in varying depth of coverage for Hawaiian Isls (Tomich, 1986); New Zealand (Moors, 1990); New Guinea (Flannery, 1995 a; Taylor et al., 1982); Moluccas and SW Pacific Isls (Flannery, 1995 b); Micronesia (Barbehenn, 1974; J. T. Marshall, Jr., 1961); Philippines (Heaney et al., 1998); Japan (Kaneko, 1994); Korea (Jones and Johnson, 1965; Won and Smith, 1999); Russia on the Svjatoj Nos peninsula and isthmus in Lake Baikal where the species is common in most human settlements (Reiter et al., 1995), the Kamchatka region (Nikanorov, 2000), SE European part of Russia (Varshavsky et al., 1989), and from Russia to Europe and Asia in general with particular regions detailed (Kucheruk, 1900); China (Wang, 2003; Zhang et al., 1997); Taiwan (Adler, 1995; M.-J. Yu, 1996); large cities, ports, and river mouths in India (Hossack, 1907) where it used to be common in Calcutta but is being gradually replaced by Bandicota bengalensis (Agrawal, 2000); Afghanistan (Hassinger, 1973); Iran (Lay, 1967); Turkey, Gökçeada Isl, and Cyprus (Kryštufek and Vohralík, 2001; Yi it et al., 1998); Serbia and Montenegro (Petrov, 1992); Slovenia (Kryštufek, 1991); Albania (Prigioni, 1996); Transylvanian Romania (Istrate, 1998); Bulgaria (Mitev and Miteva, 1991 a; Peshev, 1996); Slovakia (Danko, 1994; Kminiak, 1996; Mosansky, 1994; Stanko and Mosansky, 2000); Austria (Bauer and Spitzenberger, 1996); Czech Republic (Smaha, 1996; Zima and And�ra, 1996); Baltic region (Timm et al., 1998); Italy (Amori et al., 1999; Andreotti et al., 2001); Netherlands (Blaaderen and Bosman, 1992; Thissen and Hollander, 1969); Belgium (Libois, 1996); France (Beaufort et al., 1996; Vincent, 2001); Portugal (Santos-Reis and Mathias, 1996); Spanish Balearic Isls (Alcover and Gosalbez, 1988); Madagascar (Duplantier and Duchemin, 2003); Morocco (Aulagnier and Thevenot, 1986); Libya (Ranck, 1968); Egypt (Osborn and Helmy, 1980); Ghana and Sierra Leone (Grubb et al., 1998); Angola, where the species is restricted to coastal settlements (Crawford-Cabral, 1998); South Africa, where it is unknown outside of ports and larger coastal towns (de Graaff, 1981). Usually found only in seaports in West Africa and thought incapable of penetrating inland, R. norvegicus was found in the inland city of Bamako in S Mali by Meinig (2000). Meinig noted that fresh water, a necessity for R. norvegicus, is available all year in irrigation channels and canals and assumed that the brown rat was inadvertently transported to Bamako along the only railway line, which originates in the port city of Dakar, Senegal. Colonization of the New World by R. norvegicus reviewed by Armitage (1993).

Rattus norvegicus is thought to be native to the Hondo region of Japan because it is represented there by Holocene and late Pleistocene fossils along with a form identified as R. aff. norvegicus from the middle Pleistocene that may have been ancestral to R. norvegicus in the Japanese Isls; the rest of the endemic Japanese rodent fauna is also represented by Pleistocene and Holocene fossils (Kowalski and Hasegawa, 1976; Kawamura, 1989). Late Pleistocene-Holocene records of R. norvegicus come from cave deposits in the Sichuan-Guizhou region of China (Zheng, 1993), which adds credance to the conventional view that the original range probably also included N China (particularly in Heilongjiang Province) and SE Siberia (see references under Distribution). From their indigenous range, R. norvegicus is claimed to have reached Europe by the 18 th century, presumably through Russia (Robinson, 1984), and the British Isles during the same period (Yalden, 1999). Miljutin (1983:62) noted that while some authorities defended a much earlier invasion of Europe ("long before the beginning of our era"), geographical and historical data proves R. norvegicus could not have reached Europe "before the discovery of the Indian sea-route by Vasco da Gama, i.e. before the year of 1499." By at least 1745, the Norway rat had reached American shores, but the principal thrust of the invasion occurred between the 1760s and 1770s, coinciding with the massive wave of British immigration to the region of what would become the original 13 English colonies (Armitage, 1993).

Metamorphosis of R. norvegicus "from evil harbinger of pestilence to hero of modern medicine" is described by Clause (1993:330) who related how rat breeding and husbandry were a part of the research programs at several institutions during the early 1900s, but that it was at the Wistar Institute in Philadelphia where "the concept of the rat as an instrument for scientific research was most clearly articulated and that the engineering of a superior animal was most vigorously promoted as an objective of the institution’s scientific program." Creation, maintenance, and distribution of the famous Wistar Rats as "standardized animals" are cogently reviewed by Clause (1993).