Rattus norvegicus (mammal)

Ecology Distribution Management Info Impact Info References and Links Contacts

General Impact Norway rats are known to restrict the regeneration of many plant species by eating seeds and seedlings. They prey upon most animal species smaller than themselves such as reptiles, small birds, birds eggs and freshwater and intertidal species. Norway rats eat food crops and spoil human food stores by urinating and defecating in them. Additional economic damage is caused by rats chewing through power cables etc. and spreading diseases. Both R. norvegicus and Rattus rattus transmit the plague bacterium (Yersinia pestis) via fleas in certain areas of the world. There have been a series of recent outbreaks in Madagascar in recent years (Boiser et al. 2002).          Location Specific Impacts: Intermares (Brazil)   Threat to endangered species: Predation by the Rattus norvegicus on eggs and hatchlings of the endangered Hawksbill turtle (see Eretmochelys imbricata in IUCN Red List of Threatened Species) during the 2003/2004 and 2004/2005 nesting season was identified as a the main cause of poor nesting rates (losses of close to 3000 eggs and hatchlings were estimated) (Zeppelini et al. 2007). Anegada Is. (British Virgin Islands)   Reduction in native biodiversity: On Anegada Is. rats will be having a detrimental impact on birds, lizards and frogs through competition for food and predation of eggs, young and adults (Veitch, 1998 in Varnham, 2006). Reduction in native biodiversity: On Anegada Is. rats will be having a detrimental impact on birds, lizards and frogs through competition for food and predation of eggs, young and adults (Veitch, 1998 in Varnham, 2006). Threat to endangered species: Rattus norvegicus may predate young 'Critically Endangered (CR)' Anegada Is. rock iguana (see Cyclura pinguis in IUCN Red List of Threatened Species) on Anegada Is., and also compete with them for food resources (Veitch, 1998 in Varnham, 2006). Langara Is. (Canada)   Reduction in native biodiversity: Rattus norvegicus is implicated in the extirpation or decline of previously large seabird populations on Langara Island (Howald et al., 1999). Cayman Brac (Cayman Islands)   Habitat alteration: Rattus norvegicus is also likely to be having impacts on regeneration of native flora due to seed consumption (Burton, 2003 in Varnham, 2006). Predation: Rattus norvegicus is a predator on native snakes and lizards, including hatchling rock iguanas, and nesting birds (Burton, 2003 in Varnham, 2006). Grand Cayman (Cayman Islands)   Habitat alteration: Rattus norvegicus is also likely to be having impacts on regeneration of native flora due to seed consumption (Burton, 2003 in Varnham, 2006). Reduction in native biodiversity: Rattus norvegicus is a predator on native snakes and lizards, including hatchling rock iguanas, and nesting birds (Burton, 2003 in Varnham, 2006). Little Cayman (Cayman Islands)   Habitat alteration: Rattus norvegicus is also likely to be having impacts on regeneration of native flora due to seed consumption (Burton, 2003 in Varnham, 2006) Predation: Rattus norvegicus is a predator on native snakes and lizards, including hatchling rock iguanas, and nesting birds (Burton, 2003 in Varnham, 2006). Falkland Islands (Malvinas) (sub-Antarctic)   Habitat alteration: Brown rats may have some impacts on vegetation. Reduction in native biodiversity: The presence of rats on islands is negatively correlated with the presence of seven species of native passerines (Varnham, 2006). Threat to endangered species: Brown rats are likely to have destroyed whole poulations of 'Vulnerable (VU)' Cobb's wren (see Troglodytes cobbi in IUCN Red List of Threatened Species) and many other land and seabirds, especially burrowing petrels (BirdLife International 2006). Breeding of the Tussock bird (Cinclodes antarcticus antarcticus) has become restricted to cat- and rat-free islands. Reduction of small petrels including Antarctic prion (Pachyptila desolata) has occurred on rat-inhabited islands (In Atkinson, 1985 in Varnham, 2006). Amsterdam Is. (sub-Antarctic) (French Southern Territories)     Reduction in native biodiversity: Rattus norvegicus and cats (Felis catus) contributed to the elimination of 10 or 12 of the 22 bird species that were originally present (Micol and Jouventin, 1995). Crozet Archipelago (sub-Antarctic) (French Southern Territories)   Predation: Rattus norvegicus preys on the chicks of the subantarctic white-chinned petrel (see Procellaria aequinoctialis in IUCN Red List of Threatened Species) in the Crozet archipelago. Guadeloupe     Reduction in native biodiversity: Several authors believe that the two rat species, Rattus rattus and Rattus norvegicus and the mongoose (Herpestes javanicus) contributed to the disappearance or the extinction of various species of lizards, snakes, birds and mammals in the Lesser Antilles (in Lorvelec et al., 2001). Isle of Man   Predation: There is concern that Rattus norvegicus could be taking eggs from ground nesting birds (Charter, 2004 in Varnham, 2006). Japan   Predation: Rattus norvegicus preys on the apple snail (Pomacea canaliculata), an important pest of rice, in Japan (Yusa et al., 2000). Malta   Threat to endangered species: Predation by rats (Rattus rattus and R. norvegicus) are one of the threats facing the successful rearing of Yelkouan Shearwater chicks (see Puffinus yelkouan in IUCN Red List of Threatened Species) (BirdLife International 2004; BirdLife Malta, undated). Rdum tal-Madonna (Malta)   Threat to endangered species: Predation by rats (Rattus rattus and R. norvegicus) are one of the threats facing the successful rearing of Yelkouan Shearwater chicks (see Puffinus yelkouan in IUCN Red List of Threatened Species) (BirdLife International 2004; BirdLife Malta, undated). Martinique     Reduction in native biodiversity: Several authors believe that the two rat species, Rattus rattus and Rattus norvegicus and the mongoose (Herpestes javanicus) contributed to the disappearance or the extinction of various species of lizards, snakes, birds and mammals in the Lesser Antilles (in Lorvelec et al., 2001). Gunner's Quoin Is. (Mauritius)   Reduction in native biodiversity: The introduction of Rattus norvegicus to Gunner's Quoin is associated with the extinction of Telfairs skink (see Leiolopisma telfairii in IUCN Red List of Threatened Species) on the islet (Cheke, 1987; in MoA, 2004). Rodrigues Is. (Mauritius)   Herbivory: Rattus norvegicus causes damage to the vegetation of Mascarene islands. Predation of fallen palm fruit and seedlings is a major problem. Rasa Is. (Mexico)   Reduction in native biodiversity: Rats and mice may be responsible for the absence of nocturnal hole and crevice nesting birds on Rasa Island (Donlan et al., 2000). New Zealand   Threat to endangered species: Rattus norvegicus is a known predator of the saddleback (see Philesturnus carunculatus in IUCN Red List of Threatened Species) in New Zealand (Hooson and Jamieson, 2003). There is evidence that R. norvegicus preys on New Zealand's native snails (Bennett et al., 2002). Rakino Is. (New Zealand)   Predation: Rattus norvegicus was probably responsible for extirminating the grey-faced petrel from Rakino Island (ARC, 2002). Raoul Is. (New Zealand)   Reduction in native biodiversity: Rattus norvegicus probably contributed to the extirpation of the white-necked petrel (see Pterodroma cervicalis in IUCN Red List of Threatened Species) from Raoul Island (Birdlife International, 2005). Campbell Is./Motu Ihupuku (sub-Antarctic) (New Zealand)   Predation: It is probable that Norway rats have caused catastrophic declines in the numbers of ground-nesting birds, but no particular case has been properly documented (SPREP, 2000). Whale (Moutohora) Is. (New Zealand)   Predation: Rattus norvegicus preys on the eggs and chicks of the grey-faced petrel (Pterodroma macroptera gouldi) on Whale Island (Imber et al., 2000). Kayangel Is. (Palau)   Disease transmission: Rattus norvegicus are known to affect community health in Palau by acting as disease vectors, exposing citizens to gastrointestinal illnesses and leptospirosis through water supplies Economic/Livelihoods: Rattus norvegicus are causing economic losses by damaging crops including papaya and corn. Threat to endangered species: Ground birds such as the Micronesian megapode (see Megapodius laperouse in the IUCN Red List of Threatened Species) are particularly vulnerable to introduced predators such as rats and cats. Azores (Portugal)   Disease transmission: Rattus norvegicus plays a significant role as a maintenance host of leptospirosis in the Azores. Predation: Rats are a major factor in determining the distribution of Puffinus spp.in the Azores (Pitta Groz et al., 2002). Reunion (La Réunion)   Herbivory: Rattus norvegicus causes damage to the vegetation of Mascarene islands. Predation of fallen palm fruit and seedlings is a major problem. Reunion (La Réunion)     Reduction in native biodiversity: Recent studies have shown that herbivory by the two rats Rattus rattus and Rattus norvegicus and Achatina fulica was the main factor contributing to current decline of Aloe macra (Meyer and Picot, 2001 ; Picot, 2005). Saint Helena   Reduction in native biodiversity: Rattus norvegicus are highly omnivorous, eating plants, invertebrates and young birds (Ashmole and Ashmole, 2000 in Varnham, 2006). They may predate on 'Critically Endangered (CR)' endemic wirebird's (see Charadrius sanctaehelenae in IUCN Red List of Threatened Species) chicks and eggs (McCulloch and Norris, undated in Varnham, 2006). Sao Tome and Principe   Predation: The Guinea Lidless Skink (see Afroablepharus africana) is classified as 'Vulnerable (VU)' in the IUCN Red List of Threatened Species. It is restricted to three location on the islands of Sâo Tomé, Principé, and Rolas in the Gulf of Guinea. The main threats to this species are suspected to be loss of habitat through deforestation and predation by introduced mammals. Introduced mammals on these islands include the African civet (Civettictis civetta), Norway rat (Rattus norvegicus), ship rat (Rattus rattus), house mouse (Mus musculus), Mona monkey (Cercopithecus mona) and weasel (Mustela nivalis) (Ineich 2010). Predation: Declining populations of three endemic and 'Critically Endangered (CR)' birds the Sao Tome Ibis (see Bostrychia bocagei); the Sao Tome Canary (see Neospiza concolor) and the Sao Tome Fiscal (see Lanius newtoni) are under threat of loss of habitat and potential predation by introduced mammals that include the African civet (Civettictis civetta), ship rat (Rattus rattus), house mouse (Mus musculus), Mona monkey (Cercopithecus mona) and weasel (Mustela nivalis) (BirdLife International 2009; BirdLife International 2010; BirdLife International 2011). Feral pigs are also present and could be a threat (BirdLife International 2010). Fregate Is. (Seychelles)   Human nuisance: Rattus norvegicus were a nuisance to the plantation and hotel on Fregate Island (Millet and Shah, 2001). Reduction in native biodiversity: Rattus norvegicus impacted on the avifauna and invertebrates of Fregate Island (Millet and Shah, 2001). Sth. Georgia and Sth. Sandwich Iss (sub-Antarctic)   Predation: Rattus norvegicus take eggs and young of most burrow-nesting small petrels, and also eat penguin chicks (McIntosh and Walton, 2000 in Varnham, 2006). Other sources suggest they are only likely to predate weak or dead penguin chicks (Poncet, 2003 in Varnham, 2006). Reduction in native biodiversity: Rattus norvegicus are known to eat native plants (esp. Paradiochloa flabellata, a tussock grass), as well as invertebrates and carrion (Leader-Williams, 1985 in Varnham, 2006). Threat to endangered species: Breeding of the 'Near Threatened (NT) Antarctic pipits (see Anthus antarcticus in IUCN Red List of Threatened Species) and South Georgia pintails (Anas georgica georgica) has reportedly become restricted to rat-free habitats (in 8). However, other more recent sources say that although rats may have reduced pintail numbers and affected breeding success they have not eliminated them, and pintails are found all over South Georgia (Poncet, 2003 in Varnham, 2006). United Kingdom (UK)   Disease transmission: Rattus norvegicus present a zoonotic disease risk in the UK. Human nuisance: Rattus norvegicus causes damage to stored food and structures in the UK. Ailsa Craig (United Kingdom (UK))   Threat to endangered species: Rattus norvegicus effectively wiped out the puffin population of Ailsa Craig, by preying on eggs and chicks (see Fratercula arctica in IUCN Red List of Threatened Species. They have bred successfully on the island since the eradication of the rats (Williams, 2003). Canna Is. (United Kingdom (UK))   Reduction in native biodiversity: Norway rats threaten the seabird populations of Canna Island, as well as the native woodmouse. Lundy Is. (United Kingdom (UK))   Reduction in native biodiversity: Rattus rattus and R. norvegicus threatened breeding seabirds on Lundy Island, such as the manx shearwater and puffins (Appleton et al., 2002). Hawaii (United States (USA))   Predation: Rattus norvegicus in Hawaii are thought to be responsible for suppressing seed regeneration of endemic plants, reducing populations of native snails, and significantly limiting breeding success of many native birds (Pitt, 2004).