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Species
Rattus norvegicus (Berkenhout, 1769)
IUCN
NCBI
EOL Text
Norway rats were introduced to the Great Lakes region a long time ago. These rats are not originally from Norway, as its name would lead us to believe. The species originated in Asia, reached Europe by the mid-1500's and arrived in North America about 1775 on ships from England.
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Rights holder/Author | ©1995-2012, The Regents of the University of Michigan and its licensors |
Source | http://www.biokids.umich.edu/critters/Rattus_norvegicus/ |
Bruine ratten leven graag in de buurt van mensen, omdat daar altijd wel dekking te vinden is en wat te halen valt. Ze eten praktisch alles: zaden, granen, bieten, insecten, vlees, eieren, wormen, jonge vogels, kleine knaagdieren, slakken, amfibieën en afvalresten. Bruine ratten zijn 's nachts actief. Ze worden gegeten door uilen en roofdieren (ook de huiskat), en fel vervolgd door mensen. Ze zijn zo slim dat ze niet vaak in de val lopen.
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Rights holder/Author | Ecomare |
Source | http://www.ecomare.nl/index.php?id=4152&L=2 |
The brown rat is believed to have originated from China. It reached Europe at some point in the early 18th century and was first seen in England in 1720 (4). At present it has a very wide distribution in Britain in both urban and rural areas, but is absent from a number of smaller islands. It is widespread and common in urban areas across the globe, with the exception of some tropical and subtropical areas (4).
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Rights holder/Author | Copyright Wildscreen 2003-2008 |
Source | http://www.arkive.org/brown-rat/rattus-norvegicus/ |
This species is associated with farm buildings in rural areas. Refuse tips, sewer systems, hedges and field margins are also suitable habitats (4).
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | Copyright Wildscreen 2003-2008 |
Source | http://www.arkive.org/brown-rat/rattus-norvegicus/ |
Breeds throughout the year, particularly from spring to fall. Gestation lasts 21-24 days or up to a week longer in lactating females. Litter size is 2-14 (average about 9). Averages 6 litters per year (range 3-12). Sexually mature in 80-85 days.
"India Schedule V of the Indian Wildlife (Protection) Act, 1972, amended up to 2002."
Brown rats like to live in the vicinity of people, since there is always a place to hide and something to eat. They eat just about everything: seeds, grains, beets, insects, meat, eggs, worms, young birds, small rodents, snails, amphibians and garbage. Brown rats are active at night. They are hunted by owls and predators (including domestic cats), and fiercely pursued by people. They are so intelligent that they aren't readily caught in traps.
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Rights holder/Author | Ecomare |
Source | http://www.ecomare.nl/index.php?id=4152&L=2 |
Rattus norvegicus is a rather large member of the mouse family. On average, these rats reach nearly 400 mm nose-to-tail, and weigh 140 to 500 g. Males are usually larger than females. In natural populations, these rats are covered with coarse, brownish fur (sometimes splotched with black or white hairs) on their dorsal surface, which usually lightens to a gray or tan color nearing the underside. Various strains of these rats bred in captivity may be white, brown, or black. The ears and tail are bald. The length of the tail is shorter than the length of the body. Molars are lophodont and the dentary is 1/1-0/0-0/0-3/3. The ears of Norway rats are typically shorter than those of related species, and do not cover up the eyes when pulled down. Norway rats can be easily mistaken for black rats, however, the temporal ridges of the Norway rat are straight, whereas those of the black rat are curved.
Range mass: 140 to 500 g.
Average mass: 400 g.
Average length: 399 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average basal metabolic rate: 1.404 W.
- Calhoun, J. 1962. The Ecology and Sociology of the Norway Rat. Bethesda, MD: U.S. Department of Health, Education and Welfare.
- Avalos, L., C. Callahan. 2001. "Classification and Characteristics of Mammals" (On-line). Accessed March 28, 2004 at http://www.humboldt.edu/~cmc43/mammalcharacters.htm.
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Rights holder/Author | ©1995-2013, The Regents of the University of Michigan and its licensors |
Source | http://animaldiversity.ummz.umich.edu/accounts/Rattus_norvegicus/ |
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Norway rats don't have single mates, instead they breed with many others through their lifetime.
Mating System: polygynous ; cooperative breeder
If there is enough food and shelter Norway rats will breed throughout the year, although more births occur in spring and autumn. Females can have between 1 and 12 litters each year, though they usually have 6 to 8 litters each year. Females are pregnant for 21 to 26 days. Each litter usually contains 7 babies but some litters can have between 2 and 22 young! The young are born blind, naked, and helpless at birth; the eyes open in 14 to 17 days, and the young are weaned when 3 weeks old. Sexual maturity is reached at 3 months, although males must wait longer until they are able to challenge the dominant male.
Breeding interval: Norway rats can breed many times in a year, up to 12 times.
Breeding season: Norway rats breed throughout the year
Range number of offspring: 2.0 to 22.0.
Average number of offspring: 7.0.
Range gestation period: 26.0 (high) days.
Average weaning age: 22.0 days.
Average age at sexual or reproductive maturity (female): 3.0 months.
Average age at sexual or reproductive maturity (male): 3.0 months.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous
Average birth mass: 5.81 g.
Average number of offspring: 9.9.
Average age at sexual or reproductive maturity (male)
Sex: male: 70 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 90 days.
Young are cared for and nursed in their mother's nest until they are weaned. Soon after that they leave the nest and establish their own territory or home range.
Parental Investment: altricial ; female parental care
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | ©1995-2012, The Regents of the University of Michigan and its licensors |
Source | http://www.biokids.umich.edu/critters/Rattus_norvegicus/ |