Taxonomy
Rattus rattus | Black Rat | Francach dubh
Distribution
Status
Conservation status
Least Concern
Legal status
Third Schedule listed species under Regulations 49 & 50 in the European Communities (Birds and Natural Habitats) Regulations 2011. (Note: Regulation 50 not yet enacted). Listed as a schedule 9 species under Articles 15 & 15A of the Wildlife Order (Northern Ireland) 1985 (Article 15A not yet enacted).
First reported in the wild
Uncertain
Invasiveness
Invasive species - risk of High Impact
Irish status
Established
Introduction pathways - 1
Transport Stowaway
Introduction pathways subclass - 1
Hitchhikers on ship/boat
Invasive score
22
NAPRA Ireland risk assessed
No
Species Biology
Identification
Larger, longer tailed and with a pointed muzzle and broader longer hind feet, compared to smaller rodent species (Twigg et al.,2008). Distinguished from the brown rat (Rattus norvegicus)by having larger eyes and ears and a longer, thinner, uniform coloured tail, with hairless ears (Twigg et al., 2008). Colour not diagnostic, black rats may be brown and brown rats may be black.
Ecology
Considered an 'obligate pest', in that across all or part of their geographical range their survival is based on human agricultural production, with the level of damage varying according to the scale of the agricultural system being exploited (Alpin et al., 2003). Generally do not tend to survive well in natural ecosystems (Alpin et al., 2003) their effects on wildlife are largely confined to islands, particularly those with endemics not adapted to mammalian predators such as New Zealand (Jones et al., 2008; Towns et al., 2006). Negative impacts have been recorded for flightless invertebrates, ground-dwelling reptiles, land birds, and burrowing seabirds (Towns et al., 2006), while globally, ship or black rats have been associated with the decline in 60 indigenous vertebrate species (Towns et al., 2006) and rats in general have been 75 seabird species globally (Jones et al., 2008).
Habitat
Constructed, industrial or other artificial habitats
Reproduction
Females sexually mature at 90g, producing 3-5 litters per year, of between 5-8 pups (Twigg et al., 2008).
Pathway and vector description
One of the earliest commensal animals (animals that live in association with humans) it spread to Britain during Roman times and to Ireland at some unknown date after that (Twigg et al., 2008). Previously widespread, it has since been displaced throughout most of its range by the brown rat (Rattus norvegicus), though the species coexist on Lambay island (Twigg et al., 2008).
Mechanism of impact
Predation
Broad environment
Terrestrial
Habitat description
Obligate commensals (animals only found in association with humans) (Alpin et al., 2003), in Ireland they are restricted to Lambay Island .
Species group
Vertebrate
Native region
Tropical Asia
Similar species
Distribution
World distribution(GBIF)
Irish distribution
Established - Localised. Only population of black rats found on Lambay Island.
Native distribution
Thought to be originally from India (Twigg et al., 2008) there is some taxonomic confusion surrounding Rattus rattus and there are a number of sub-species or perhaps different species globally.
Temporal change
Date of first record category
Pre-1900
Fifty year date category
Pre-1500
Records submitted to Data Centre in 2024
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How can you help
Report any sightings to the National Biodiversity Data Centre.
Further information
Invasive Species Specialist Group (ISSG) of the SSC- Species Survival Commission of the IUCN -International Union for Conservation Nature 100 Worst Invaders globally.
References
Publications
Aplin, K. P., Chesser, T., & Have, J. T. (2003). Evolutionary biology of the genus Rattus: profile of an archetypal rodent pest. In: Singleton GR, Hinds LA, Krebs CJ, Spratt DM (eds) Rats, mice and people: rodent biology and management. ACIAR, Canberra, pp 487–498. Feng, A. Y., & Himsworth, C. G. (2014). The secret life of the city rat: a review of the ecology of urban Norway and black rats (Rattus norvegicus and Rattus rattus). Urban ecosystems, 17(1), 149-162 Twigg, G.I., Buckle, A.P. & Bullock, D.J. (2008). Genus Rattus Ship rat - Rattus rattus In: Mammals of the British Isles : Handbook, 4th edition Harris, S. & Yalden, D.W. (eds) The Mammal Society, UK. Jones, H. P., Tershy, B. R., Zavaleta, E. S., Croll, D. A., Keitt, B. S., Finkelstein, M. E., & Howald, G. R. (2008). Severity of the effects of invasive rats on seabirds: a global review. Conservation Biology, 22(1), 16-26. Towns, D. R., Atkinson, I. A., & Daugherty, C. H. (2006). Have the harmful effects of introduced rats on islands been exaggerated?. Biological invasions, 8(4), 863-891.
Relevant links
Global Invasive Species Database