Editing Brown rat (section)

== Description ==
[[File:Comparison Black Rat Brown Rat EN.svg|thumb|290px|Comparison of the physique of a [[black rat]] (''Rattus rattus'') with a brown rat (''Rattus norvegicus'')]]
The [[fur]] is usually brown or dark grey, while the underparts are lighter grey or brown. The brown rat is a rather large murid and can weigh twice as much as a [[black rat]] (''Rattus rattus'') and many times more than a [[house mouse]] (''Mus musculus''). The head and body length ranges from {{cvt|15|to|28|cm}} while the tail ranges in length from {{cvt|10.5|to|24|cm}}, therefore being shorter than the head and body. Adult weight ranges from {{cvt|140|to|500|g}}.<ref>{{cite web|url=http://www.mammal.org.uk/species-hub/full-species-hub/discover-mammals/species-brown-rat/|title=Brown rat – ''Rattus norvegicus''|publisher=[[The Mammal Society]]|date=n.d.|access-date=23 May 2018|archive-url=https://web.archive.org/web/20180524081925/http://www.mammal.org.uk/species-hub/full-species-hub/discover-mammals/species-brown-rat/|archive-date=24 May 2018}}</ref><ref>{{Cite web|url=http://eol.org/pages/328448/overview|title=Brown rat - Rattus norvegicus|publisher=Encyclopedia of Life|date=n.d.|access-date=23 May 2018}}</ref><ref name="IEM">{{Cite book |url=https://books.google.com/books?id=WLIOwLemzyQC&pg=PA298|title=International Wildlife Encyclopedia |last1=Burton|first1=M. |last2=Burton|first2=R. |name-list-style=amp |publisher=Marshall Cavendish |year=2002|isbn=978-0-7614-7288-9|edition=Third|location=New York|pages=298–299|language=en}}</ref><ref name="TNHCM">{{Cite book|title=The Natural History of Canadian Mammals |last=Naughton|first=D. |publisher=University of Toronto Press|location=Toronto|pages=204–206|year=2012|isbn=978-1-4426-4483-0}}</ref> Large individuals can reach {{cvt|800|g}} but are not expected outside of domestic specimens. Stories of rats attaining sizes as big as cats are exaggerations, or misidentifications of larger rodents, such as the [[coypu]] and [[muskrat]]. It is common for breeding wild brown rats to weigh (sometimes considerably) less than {{cvt|300|g}}.<ref>{{cite journal |last1=Clark |first1=B.R. |last2=Price |first2 = E.O. |name-list-style=amp |year=1981 |title=Sexual maturation and fecundity of wild and domestic Norway rats (''Rattus norvegicus'') |journal=Journal of Reproduction and Fertility | volume = 63 | issue = 1| pages = 215–220 | doi=10.1530/jrf.0.0630215 |pmid=7277322 |doi-access=free}}</ref><ref>Leslie, P. H., Perry, J. S., Watson, J. S., & ELTON, C. (1946). ''The Determination of the Median Body-Weight at which Female Rats reach Maturity''. In Proceedings of the Zoological Society of London (Vol. 115, No. 3-4, pp. 473–488). Blackwell Publishing Ltd.</ref>  The heaviest live brown rat on record is {{convert|29|oz|g|round=0.5|abbr=on|order=flip}} and they can reach a maximum length of {{convert|19|in|cm|round=0.5|abbr=on|order=flip}}.<ref>Corrigan, Robert. (2001). ''[https://books.google.com/books?id=l5X0AQAACAAJ Rodent Control: A Practical Guide For Pest Management Professionals]''. {{ISBN|1883751160|978-1883751166}}</ref>

Brown rats have acute [[hearing (sense)|hearing]], are sensitive to [[ultrasound]], and possess a very highly developed [[olfactory sense]]. Their average [[heart rate]] is 300 to 400 beats per minute, with a respiratory rate of around 100 per minute. The [[Visual acuity|vision]] of a pigmented rat is poor, around 20/600, while a non-pigmented (albino) with no melanin in its eyes has both around 20/1200 vision and a terrible scattering of light within its vision. Brown rats are [[dichromacy|dichromats]] which perceive colors rather like a human with [[red-green colorblindness]], and their colour saturation may be quite faint. Their blue perception, however, also has UV receptors, allowing them to see ultraviolet lights that humans and some other species cannot.<ref>{{cite web |last=Hanson, A. |title=What Do Rats See? |work=Rat Behavior and Biology |publisher=ratbehavior.org  | date=2007 |url=http://www.ratbehavior.org/RatVision.htm |access-date=1 December 2007}}</ref>