Tanezumi Rat (Rattus tanezumi)
Both the native and introduced geographic distribution
of this very widespread species remains somewhat unclear. We follow Musser and
Carleton (2005) who consider the species native distribution to range from
Eastern Afghanistan (Niethammer and Martens 1975) through Central and Southern
Nepal (below about 2,000 m asl), Bhutan, Northern India, Northern Bangladesh and
North-Eastern India (distributional relationships between R. rattus and R.
tanezumi along the Northern portion of the Indian subcontinent still
requires resolution) into Southern and Central China (including Hainan Island),
the Korean Peninsula, and mainland Southeast Asia (including offshore islands)
south to the Isthmus of Kra, being also probably native to Mergui Archipelago.
Musser and Carleton (2005) report that it is presently unclear whether the
species is native or introduced to Taiwan and Japan. But is most likely
introduced to Peninsular Malaysia and islands on the Sunda Shelf and nearby
archipelagos, including the Mentawai Islands (Musser and Califia 1982; Musser
and Newcomb 1983). It has been introduced to Little Nicobar and Great Nicobar,
in the Andaman and Nicobar Islands of India. It has been widely introduced
throughout the Philippines (Heaney et al. 1998; Musser and Carleton 2005; Larry
Heaney pers. comm.). It appears to have been widely introduced throughout
insular Southeast Asia, including the Greater and Lesser Sunda Islands and the
Molucca Islands, to Western New Guinea (range map very provisional for this
island) (Flannery 1995), and from here into Micronesia to the islands of
Eniwetok and Fiji (Musser and Carleton 2005).
Afghanistan; Bangladesh; Bhutan; Cambodia; China; India; Japan; Korea, Democratic People's Republic of; Korea, Republic of; Lao People's Democratic Republic; Malaysia; Nepal; Taiwan, Province of China; Thailand; Vietnam
Fiji; Indonesia; Papua New Guinea; Philippines
The fur on the
dorsal side is olive-brown, and the ventral side generally lighter. The tail is
very dark grey and nearly naked. The ears are large and the eyes jet black.
Juveniles have a relatively larger head and smaller body. Head-Body Length : Up
to 22cm Tail Length : Up to 22cm Weight : Up to 200 grams. Rattus
tanezumi is the oldest name for the 2n = 42 group of Asian house rats that is
distinguished from the 2n = 38/40 Rattus rattus not only by chromosomal
characters but also morphological and biochemical traits (Wilson, 2005) Many
endoparasites infecting the different viscera of R. tanezumi belong to taxonomic
groups Nematoda (roundworms), Cestoda (tapeworms), and Trematoda (flukes). The
more important ones are those that are transmissible to humans. In contrast,
there have been few reports on the ectoparasites that infest these rats. These
are the mites, ticks, and fleas, some of which may serve as vectors of microbial
infections to humans and domestic animals. Rattus tanezumi is an alternative
meat source for the rural folk. Rat meat is a favourite accompaniment to
alcoholic beverages during drinking sprees. Unknowingly, some zoonotic
infections can be transmitted to humans through improperly cooked rat meat and
viscera, accidental wound contamination with rat urine, or rat bites during
handling and precooking preparations
This species is regularly misidentify with Rattus rattus and treated as Rattus rattus species group and often confused in field with Rattus argentiventer, Rattus andamanensis and Rattus tiomanicus .
he species is closely related to the European House Rat Rattus rattus, but recent studies suggest it is a separate species. It probably occurs throughout Southeast Asia.
It is a common to abundant species.
Population Trend: Increasing
Habitat and Ecology:
This highly adaptable species is commonly found in and around
villages and agricultural areas. In the Philippines it is common in disturbed
lowland and montane forest up to 1,800 m (Danielsen et al. 1994; Heaney et al.
1989. A supremely adaptable species, is to be found in many man-made habitats
including agricultural and wholly urban areas. It is omnivorous, feeding on all
manner of farmyard waste and food scraps. It is a fast runner, can climb well
and can jump up to 50 cm.
There are no major threats to this species.
It is presumably present in numerous protected areas. No direct conservation measures are needed for this common and adaptable species. There is a need to further study the taxonomic relationships between populations of Rattus currently allocated to this species.