Black rat
Black rat Temporal range: Holocene
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Rodentia |
Family: | Muridae |
Genus: | Rattus |
Species: | R. rattus
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Binomial name | |
Rattus rattus | |
Synonyms | |
Mus rattus Linnaeus, 1758 |
The black rat (Rattus rattus), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus Rattus, in the subfamily Murinae.[1] It likely originated in the Indian subcontinent, but is now found worldwide.[2]
The black rat is black to light brown in colour with a lighter underside. It is a generalist
Taxonomy
Mus rattus was the
Three subspecies were once recognized, but today are considered invalid and are now known to be actually
- Rattus rattus rattus – roof rat
- Rattus rattus alexandrinus – Alexandrine rat
- Rattus rattus frugivorous – fruit rat
Characteristics
A typical adult black rat is 12.75 to 18.25 cm (5.02 to 7.19 in) long, not including a 15 to 22 cm (5.9 to 8.7 in) tail, and weighs 75 to 230 g (2.6 to 8.1 oz), depending on the subspecies.[4][5][6][7] Despite its name, the black rat exhibits several colour forms. It is usually black to light brown in colour with a lighter underside. In England during the 1920s, several variations were bred and shown alongside domesticated brown rats. This included an unusual green-tinted variety.[8]
Origin
Black rat bone remains dating to the
It is a resilient
Distribution and habitat
The black rat originated in India and Southeast Asia, and spread to the
Black rat populations can increase exponentially under certain circumstances, perhaps having to do with the timing of the fruiting of the bamboo plant, and cause devastation to the plantings of subsistence farmers; this phenomenon is known as mautam in parts of India.[18]
Black rats are thought to have arrived in Australia with the First Fleet, and subsequently spread to many coastal regions in the country.[19]
Black rats adapt to a wide range of habitats. In urban areas they are found around warehouses, residential buildings, and other human settlements. They are also found in agricultural areas, such as in barns and crop fields.[20] In urban areas, they prefer to live in dry upper levels of buildings, so they are commonly found in wall cavities and false ceilings. In the wild, black rats live in cliffs, rocks, the ground, and trees.[21] They are great climbers and prefer to live in palms and trees, such as pine trees. Their nests are typically spherical and made of shredded material, including sticks, leaves, other vegetation, and cloth. In the absence of palms or trees, they can burrow into the ground.[22] Black rats are also found around fences, ponds, riverbanks, streams, and reservoirs.[23]
Behaviour and ecology
It is thought that male and female rats have similarly sized home ranges during the winter, but male rats increase the size of their home range during the breeding season. Along with differing between rats of different sex, home range also differs depending on the type of forest in which the black rat inhabits. For example, home ranges in the southern beech forests of the South Island, New Zealand appear to be much larger than the non-beech forests of the North Island. Due to the limited number of rats that are studied in home range studies, the estimated sizes of rat home ranges in different rat demographic groups are inconclusive.
Diet and foraging
Black rats are considered omnivores and eat a wide range of foods, including seeds, fruit, stems, leaves, fungi, and a variety of invertebrates and vertebrates. They are generalists, and thus not very specific in their food preferences, which is indicated by their tendency to feed on any meal provided for cows, swine, chickens, cats and dogs.[23] They are similar to the tree squirrel in their preference of fruits and nuts. They eat about 15 g (0.53 oz) per day and drink about 15 ml (0.53 imp fl oz; 0.51 US fl oz) per day.[22] Their diet is high in water content.[23] They are a threat to many natural habitats because they feed on birds and insects. They are also a threat to many farmers, since they feed on a variety of agricultural-based crops, such as cereals, sugar cane, coconuts, cocoa, oranges, and coffee beans.[24]
The black rat displays flexibility in its foraging behaviour. It is a predatory species and adapts to different micro-habitats. It often meets and forages together in close proximity within and between sexes.[25] It tends to forage after sunset. If the food cannot be eaten quickly, it searches for a place to carry and hoard to eat at a later time.[23] Although it eats a broad range of foods, it is a highly selective feeder; only a restricted selection of the foods is dominating.[26] When offered a wide diversity of foods, it eats only a small sample of each. This allows it to monitor the quality of foods that are present year round, such as leaves, as well as seasonal foods, such as herbs and insects. This method of operating on a set of foraging standards ultimately determines the final composition of its meals. Also, by sampling the available food in an area, it maintains a dynamic food supply, balance its nutrient intake, and avoids intoxication by secondary compounds.[26]
Nesting behaviour
Through the usage of tracking devices such as radio transmitters, rats have been found to occupy dens located in trees, as well as on the ground. In Puketi Forest in the Northland Region of New Zealand, rats have been found to form dens together. Rats appear to den and forage in separate areas in their home range depending on the availability of food resources.[25] Research shows that, in New South Wales, the black rat prefers to inhabit lower leaf litter of forest habitat. There is also an apparent correlation between the canopy height and logs and the presence of black rats. This correlation may be a result of the distribution of the abundance of prey as well as available refuges for rats to avoid predators. As found in North Head, New South Wales, there is positive correlation between rat abundance, leaf litter cover, canopy height, and litter depth. All other habitat variables showed little to no correlation.[27] While this species' relative, the brown (Norway) rat prefers to nest near the ground of a building the black rat will prefer the upper floors and roof. Because of this habit they have been given the common name roof rat.
Diseases
Black rats (or their
Rats serve as outstanding vectors for transmittance of diseases because they can carry bacteria and viruses in their systems. A number of bacterial diseases are common to rats, and these include Streptococcus pneumoniae, Corynebacterium kutsheri, Bacillus piliformis, Pasteurella pneumotropica, and Streptobacillus moniliformis, to name a few. All of these bacteria are disease causing agents in humans. In some cases, these diseases are incurable.[35]
Predators
The black rat is prey to cats and owls in domestic settings. In less urban settings, rats are preyed on by weasels, foxes, and coyotes. These predators have little effect on the control of the black rat population because black rats are agile and fast climbers. In addition to agility, the black rat also uses its keen sense of hearing to detect danger and quickly evade mammalian and avian predators.[23]
As an invasive species
Damage caused
After Rattus rattus was introduced into the northern islands of New Zealand, they fed on the seedlings, adversely affecting the ecology of the islands. Even after eradication of R. rattus, the negative effects may take decades to reverse. When consuming these seabirds and seabird eggs, these rats reduce the pH of the soil. This harms plant species by reducing nutrient availability in soil, thus decreasing the probability of seed germination. For example, research conducted by Hoffman et al. indicates a large impact on 16 indigenous plant species directly preyed on by R. rattus. These plants displayed a negative correlation in germination and growth in the presence of black rats.[36] Rats prefer to forage in forest habitats. In the
Complex pest
The black rat is a complex pest, defined as one that influences the environment in both harmful and beneficial ways. In many cases, after the black rat is introduced into a new area, the population size of some native species declines or goes extinct. This is because the black rat is a good generalist with a wide dietary
Despite the black rat's tendency to displace native species, it can also aid in increasing species population numbers and maintaining species diversity. The bush rat, a common vector for spore dispersal of
Control methods
Large-scale rat control programs have been taken to maintain a steady level of the invasive predators in order to conserve the native species in New Zealand such as
In 2010, the Sociedad Ornitológica Puertorriqueña (Puerto Rican Bird Society) and the
Decline in population
Eradication projects have eliminated black rats from Lundy in the Bristol Channel (2006)[43] and from the Shiant Islands in the Outer Hebrides (2016).[44] Populations probably survive on other islands (e.g. Inchcolm) and in localised areas of the British mainland.[45] Recent National Biodiversity Network data show populations around the U.K., particularly in ports and port towns.[46]
See also
- Karni Mata Temple, Deshnoke, Rajasthan, India.
- Polynesian rat
- Urban plague
References
- ^ . Retrieved 19 November 2021.
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- ^ Linnæus, C. (1758). "Mus rattus". Caroli Linnæi Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I (in Latin) (Decima, reformata ed.). Holmiae: Laurentius Salvius. p. 61.
- WAZA.org. Archived from the originalon 19 October 2016. Retrieved 19 October 2016.
- ^ Gillespie, H. (2004). "Rattus rattus – house rat". Animal Diversity Web.
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- ^ url=https://www.history.com/news/rats-didnt-spread-the-black-death-it-was-humans
- ^ "Black Death 'spread by humans not rats'". BBC News. 15 January 2018. Retrieved 6 March 2023.
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- ^ Teisha Rowland (4 December 2009). "Ancient Origins of Pet Rats". Santa Barbara Independent. Archived from the original on 24 September 2015.
- ^ "Nova: Rat Attack". Nova. 7 April 2010. PBS.
- ^ Evans, Ondine (1 April 2010). "Animal Species: Black Rat". Australian Museum website. Sydney, Australia: Australian Museum. Retrieved 31 December 2010.
- ^ Tech, Texas. "Black Rats". Natural Science Research Laboratory. Retrieved 15 February 2024.
- ^ "Rattus Rattus". Pest Solutions. 22 November 2022. Retrieved 15 February 2024.
- ^ a b Bennet, Stuart M. "The Black Rat (Rattus Rattus)". The Pied Piper. Retrieved 22 April 2011.
- ^ a b c d e Marsh, Rex E. (1994). "Roof Rats". Internet Center for Wildlife Damage Management. Prevention and Control of Wildlife Damage. Archived from the original on 21 May 2011. Retrieved 22 April 2011.
- ^ "Rattus rattus – Roof rat". Pest Solutions. 22 November 2022. Retrieved 15 February 2024.
- ^ a b c Dowding, J.E. & Murphy, E.C. (1994). "Ecology of Ship Rats (Rattus rattus) in a Kauri (Agathis australis) Forest in Northland, New Zealand" (PDF). New Zealand Journal of Ecology. 18 (1): 19–28.
- ^ JSTOR 1936797.
- .
- ^ Hafidzi, M.N.; Zakry, F.A.A. & Saadiah, A. (2007). "Ectoparasites of Rattus sp. from Petaling Jaya, Selangor, Malaysia". Pertanika Journal of Tropical Agricultural Science. 30 (1): 11–16.
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- ^ Last, John M. "Black Death", Encyclopedia of Public Health, eNotes website. Retrieved 31 December 2010.
- ISBN 978-0-8263-3066-6, p. 247.
- ISBN 978-1-888799-79-8, p. 23
- ISBN 978-0-7637-0234-2, p. 162.
- ISBN 978-1-85109-658-9, p. 64.
- ^ Boschert, K. (1991). "Rat Bacterial Diseases". Net Vet and the Electronic Zoo. Archived from the original on 18 October 1996. Retrieved 22 April 2011.
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- .
- ^ .
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- ^ Innes, J.; Warburton, B.; Williams, D. (1995). "Large-Scale Poisoning of Ship Rats (Rattus rattus) in Indigenous Forests of the North Island, New Zealand" (PDF). New Zealand Journal of Ecology. 19 (1): 5–17. Archived from the original (PDF) on 27 September 2011. Retrieved 22 April 2011.
- ^ Wege, David (4 August 2010) Restauran hábitat del lagartijo del seco Anolis cooki en la Isla de Cardona y Cayo Ratones Archived 14 August 2011 at the Wayback Machine. birdlife.org.
- ^ Lock, J. (2006). "Eradication of brown rats Rattus norvegicus and black rats Rattus rattus to restore breeding seabird populations on Lundy Island, Devon, England". Conservation Evidence: 111–113.
- ISBN 978-2-8317-1962-7.
- ^ "Revealed: Historic Scottish island home to black rats". 31 December 2018.
- ^ "NBN Gateway – Taxon". data.nbn.org.uk. Retrieved 11 August 2016.
Further reading
External links
- Photos and video at ARKive