Common Sri Lanka House Rat (Rattus rattus kandianus)
Brown Rat (Rattus norvegicus)
Ricefield Rat (Rattus argentiventer)
Malaysian field rat or Malaysian wood rat, (Rattus tiomanicus)
Black Rat (Rattus rattus)
The Ricefield Rat (Rattus argentiventer) is a species of rat found throughout Southeast Asia.
The ricefield rat is a medium-sized rat with a grizzled yellow-brown and black pelage. Its belly is gray in the midline with whiter flanks. The tail is uniformly medium brown. They have chisel-like incisor. The ricefield rat is between 304–400 mm long with a tail length of 140–200 mm and a skull length of 37–41 mm. The average weight of Rattus argentiventer is around 97 to 219 g. Female have 12 mammae. Young have an orange-colored tuft in front of each ear.
The ricefield rat lives in large groups which consist of a dominant male and high ranking female. When attacked or disturbed they will make squeals and whistles sound. Rattus argentiventer's main diet includes termites, insects, grasshopper, snails, seeds, nuts, rice, vegetables, and fruits. They feed at night and actively moving at dusk and dawn. During daytime, they can be seen among vegetation, weeds or maturing field. It undergoes 3 week gestation giving birth about 5 to 10 young per litters.
The ricefield rat can be found throughout Southeast Asia consists of Indochina region, Thailand, Peninsular Malaysia, Indonesia, Philippine, and New Guinea as major rodent pest in rice field area.
Although not a part of staple human diet in Cambodia, a growing market has developed there with most exports going to Vietnam. Rat-catching season reaches its height after the rice harvest in June and July when rats have little to eat. That lack of food coincides with seasonal rains that force the rodents onto higher ground, where traps are set up to catch them.
The Brown Rat (Rattus norvegicus), also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat, Norwegian rat and Parisian rat, is a widespread species of common rat. One of the largest muroids, it is a brown or grey rodent with a head and body length of up to 28 cm (11 in) long, and a tail slightly shorter than that. It weighs between 140 and 500 g (5 and 17+3⁄4 oz). Thought to have originated in northern China and neighbouring areas, this rodent has now spread to all continents except Antarctica, and is the dominant rat in Europe and much of North America. With rare exceptions, the brown rat lives wherever humans live, particularly in urban areas.
Selective breeding of the brown rat has produced the fancy rat (rats kept as pets), as well as the laboratory rat (rats used as model organisms in biological research). Both fancy rats and laboratory rats are of the domesticated subspecies Rattus norvegicus domestica. Studies of wild rats in New York City have shown that populations living in different neighborhoods can evolve distinct genomic profiles over time, by slowly accruing different traits.
Rattus norvegicus - Brown Rat - Similan Islands Marine Park Thailand & Bangkok
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. It likely originated in the Indian subcontinent, but is now found worldwide.
The black rat is black to light brown in colour with a lighter underside. It is a generalist omnivore and a serious pest to farmers because it feeds on a wide range of agricultural crops. It is sometimes kept as a pet. In parts of India, it is considered sacred and respected in the Karni Mata Temple in Deshnoke.
The black rat originated in India and Southeast Asia, and spread to the Near East and Egypt, and then throughout the Roman Empire, reaching Great Britain as early as the 1st century AD. Europeans subsequently spread it throughout the world. The black rat is again largely confined to warmer areas, having been supplanted by the brown rat (Rattus norvegicus) in cooler regions and urban areas. In addition to the brown rat being larger and more aggressive, the change from wooden structures and thatched roofs to bricked and tiled buildings favored the burrowing brown rats over the arboreal black rats. In addition, brown rats eat a wider variety of foods, and are more resistant to weather extremes.
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.
Black rats are thought to have arrived in Australia with the First Fleet, and subsequently spread to many coastal regions in the country.
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. 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.[14] 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.[13] Black rats are also found around fences, ponds, riverbanks, streams, and reservoirs.
Rattus rattus kandianus - Common Sri Lanka House Rat - Horton Plains. Possible new species.
Rattus rattus sbsp. nilgiri - Nilgiri House Rat, Valparai Tamil Nadu
The Malayan field rat, Malaysian field rat or Malaysian wood rat, (Rattus tiomanicus) is a species of rodent in the family Muridae. It is nocturnal and mainly arboreal and is found in Malaysia, Thailand, Indonesia and the Philippines. It is a common species and the International Union for Conservation of Nature has assessed it as being of "least concern".
The Malayan field rat has a head-and-body length of 140 to 190 mm (5.5 to 7.5 in) and a tail 150 to 200 mm (6 to 8 in). It has a weight of between 55 and 150 g (2 and 5 oz). The ears are large and nearly naked. The fur is smooth and flattened, interspersed with short spines. The dorsal pelage is a grizzled olive-brown with scattered medium-length black guard hairs, and the underparts are whitish. The tail, which is a similar length to the body, is a uniform dark brown. The feet are broad, and the soles have fine ridges for climbing. It differs from Annandale's rat (Rattus annandalei) in having sleek fur with spines and fewer mammae, and from the ricefield rat (Rattus argentiventer) in having plain white underparts and lacking an orange spot in front of the ear.
The Malayan field rat is known from Malaysia, Thailand, Sumatra, Borneo, the Philippines and many smaller islands. Its typical habitat is primary and secondary forest, including coastal forest but it is seldom found in dipterocarp forests. It is also found in plantations, shrubby areas, grassland and gardens, but seldom invades buildings. This individual is from my home in Koh Lanta Thailand.
