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Order : RODENTIA
Family : Muridae
Species : Rattus norvegicus
Head-Body Length : Up to 26 cm
Tail Length : Up to 25 cm
Weight : Up to 500 grams
The Brown Rat is a highly
successful murid which, over many centuries, has established itself in
coastal towns and cities throughout the world by hitching a ride on vessels
plying the world's trade routes.
The species has many other names including Sewer Rat, Wharf Rat and Norway
Rat. The latter name, which is also used for its scientific name Rattus
norvegicus, is a misnomer : the species did not originate in Norway,
but from the Far East (either China, Russia or Japan).
In natural habitats it builds extensive burrow systems, but in urban
areas it has adapted to man-made subterranean structures including drains
and sewers.
Rattus
norvegicus is considered an unwanted pest, which can pose some threat to
human health by the spread of disease. Efforts to completely eradicate it from urban areas are usually
unsuccessful as its numbers can rapidly increase where there is available
food. Reportedly a single female can bear up to 5 litters per years, each with an
average of 7 young.
This is a relatively large, terrestrial rat (and a strong swimmer), with some males weighing up to
500 grams or more. It has well developed haunches and a relatively large
head.
Its coarse fur is brown to brownish grey on its upperside and flanks : this
grades into pale fur on the underside and chest. Its tail is
thick, being slightly shorter than its head-body length,
and is typically dark above and pale below, with sparse hairs. Its ears and eyes are small.
The Brown Rat has localised populations in most countries in Southeast Asia
and around the world.
Figs 1 to 3 : Example seen perched on debris in a large monsoon drain
running beneath a major urban road in Singapore.
Figs 4 : Searching for scraps near a residential area at night.
References :
Francis, C.M. 2019. A Field Guide to the Mammals of South-east Asia. Second
Edition. New Holland. 416 pp.
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