RATS
Rodents comprise the largest group in the mammalian kingdom, representing 42% of all mammal species. There are four families of rodents, the largest of which is the Muridae family. All of the rats featured below are part of a sub-family called Murinae (Murine rodents).
Rat populations exhibit very high reproductive rates, females often being able to produce litters of between 4 and 8 young every 4 to 5 weeks. They are also very intelligent, adaptable and agile. Their incisor teeth grow continuously throughout their lives and are strong and sharp – they are able to gnaw through wood, lead, aluminium, tin and even concrete. Rats are abundantly present in Myanmar, often causing serious economic loss and damage, as well as placing both the environment and the health of the human population at risk.
In Myanmar, they include the following species:
NORWAY RAT (Rattus norvegicus)
APPEARANCE:
A large, burrowing rat, weighing up to 700gm but usually in the range 350 – 450gm and on average about 25cm in head-body length. The body of the Norway rat is covered in shaggy fur that is brown or gray in colour. The ears and tail are small, the tail being shorter than the head-body length and the muzzle is blunt. Females have 12 teats (vs the Roof rat with 10 and the Polynesian rat with 8).
BEHAVIOUR AND DIET:
The Norway rat is able to live in a wide range of man-made habitats including drains, sewers, farms, domestic houses, warehouses, rubbish tips, restaurants and other terrestrial environments. Norway rats typically nest in underground burrows, from which they enter buildings in search of food. They tend to remain in hiding during the day.
Norway rats are omnivorous and feed on a variety of food sources. If given the choice, they will consume meats, fruits, grains and nuts. They require water to drink and they position their colony as close to a water source as possible. Norway rats live in communities with dominant and subordinate members, though they are not truly social.
REPRODUCTION:
Like most rodents, the Norway rat has a high breeding rate and female rats can breed throughout the year, potentially producing average litter sizes of 6 – 10 pups every 4 – 6 weeks.
VISUAL SIGHTINGS – Sightings of live or dead rodents clearly indicate rodent activity. Live sightings, especially during the day, can point to nest disturbance or possibly an infestation, the latter which can sometimes lead rats to forage during the day, when there is less competition for food.
BURROWS / NESTS – Typically found at ground level and outside in the vicinity of buildings and structures. However, are also found in basements of poorly maintained buildings.
GNAWING DAMAGE – Like all rodents they have very strong teeth and can damage almost any material they encounter, including electrical cables and wires, wood, lead and other metals, building construction and household materials.
DROPPINGS – Norway rat droppings are shaped like a capsule, with rounded ends and 18 to 20 cm long.
GREASE SMEARS – Grease marks are produced as the rodent travels along an edge, and oils in their fur are deposited.
DISEASE TRANSMITTERS – Norway rats have been shown to carry a very wide range of diseases that can infect humans and livestock, including leptospirosis, salmomellosis, toxoplasmosis, cryptosporidiosis, rat bite fevers and many additional infections. These diseases are often spread by the faeces and urine with which they contaminate their environment as well as fleas that they usually carry.
ECONOMIC IMPACT – Rodents destroy structures such as walls, floors and doors; electrical wiring; plumbing; fuel lines and furniture. They consume and contaminate food supplies and consumer goods. Insurance companies estimate that approximately 25% of all building fires are caused by rodents gnawing through electrical cables.
Ensure that all points of ingress to buildings are properly sealed – pay particular attention to where utilities are brought in to buildings – adult rats can scramble through holes of less than an inch and juveniles, even less. Where these points of ingress are doors and windows of less than 1.25m off the ground, ensure that they remain shut when not in use and are tight fitting to their architraves. If your building is connected to another, ensure that any adjoining roof spaces are adequately sealed.
Keep foodstuffs tightly contained in metal or glass containers with tight fitting lids.
Keep clutter to a minimum, both inside and outside buildings — less clutter means less places to hide and to build a home.
Outdoor Rubbish – Place outdoor rubbish bags in metal bins with securely fitted lids, to prevent access to the contents.
Solution – Please see our rodent control page for more practical steps you can take to help prevent rodent infestations and also for our own specialist solutions.
ROOF RAT (Rattus rattus)
APPEARANCE:
Roof rats have a long tail, large ears, pointed muzzle and weigh around 150 – 250 gms and are typically 12 to 18cm in head-body length. Their body is smaller and sleeker than that of the Norway rat and their fur is smooth. Females have 10 teats and on some very rare occasions 12 (vs the Polynesian rat with 8 and the Norway rat with 12).
BEHAVIOUR AND DIET:
A far better climber than either Norway rats or Lesser Bandicoot rats, the Roof rat will very frequently use the upper and higher areas of habitats for movements, shelter and nesting if available. They prefer to consume fruits (sometimes referred to as the “fruit rat” or “citrus rat”) and nuts, although roof rats are omnivorous and will feed on almost anything available to them.
REPRODUCTION:
The Roof rat will breed all year round in urban areas but may be more cyclical in rural areas. In suitable environments, Roof rats can have litters averaging 4 – 8 every 4/5 weeks.
VISUAL SIGHTINGS. Sightings of live or dead rodents clearly indicate rodent activity. Live sightings, especially during the day, can point to nest disturbance or possibly an infestation, the latter which can sometimes lead rats to forage during the day, when there is less competition for food.
BURROWS / NESTS. In built up areas, nests are often constructed in roof spaces (unlike the Norway rat, whose nests are typically found at ground level), wall cavities and under floor boards. Outside they can be found under sheds and rubbish piles, and burrows in grassy banks.
GNAWING DAMAGE. Like all rodents they have very strong teeth and can damage almost any material they encounter, including electrical cables and wires, wood, lead and other metals, building construction and household materials.
DROPPINGS. 12 to 13 mm in length with pointed ends (distinctive from Norway rat droppings, which are 18 to 20 mm and capsule shaped).
GREASE SMEARS. Grease marks are produced as the rodent travels along an edge, and oils in their fur are deposited.
DISEASE TRANSMITTERS. Roof rats have been shown to carry a very wide range of diseases that can infect humans and livestock, including leptospirosis, salmomellosis, toxoplasmosis, cryptosporidiosis, rat bite fevers and many additional infections. These diseases are often spread by the faeces and urine with which they contaminate their environment as well as fleas that they usually carry.
ECONOMIC IMPACT. Rodents destroy structures such as walls, floors and doors; electrical wiring; plumbing; fuel lines and furniture. They consume and contaminate food supplies and consumer goods. Insurance companies estimate that approximately 25% of all building fires are caused by rodents gnawing through electrical cables.
PACIFIC RAT (Rattus exulans)
APPEARANCE:
A small (20 – 40 gm and approx 15cm in head-body length), large eyed, reddish brown to grey brown rat. Tail is sometimes longer than the head-body length and they have largely hairless ears and a pointed muzzle. Females have 8 teats (vs the Roof rat with 10 and the Norway rat with 12).
BEHAVIOUR AND DIET:
Arboreal, (but less so than the Roof rat), they can sometimes be seen climbing low bushes and trees. Not so able to compete with the larger and more aggressive Roof rat or Norway rat, when habitats coincide and is more likely to be found in villages and household gardens, than heavily built-up urban areas.
REPRODUCTION:
Litter sizes are normally between 6 – 11, and females can be sexually active all year round, having up to six litters a year.
VISUAL SIGHTINGS. Sightings of live or dead rodents clearly indicate rodent activity. Live sightings, especially during the day, can point to nest disturbance or possibly an infestation, the latter which can sometimes lead rats to forage during the day, when there is less competition for food. It should be noted that although commensal (closely associated with man), their preferred habitat is rural areas near man and they are less common in urban areas.
BURROWS / NESTS. Less of a burrower and more of a digger, nests are mainly found at ground level (in common with the Norway rat) and can be found in burrows, rock piles, rock walls and embankments.
DISEASE TRANSMITTERS. Polynesian rats have been shown to carry a very wide range of diseases that can infect humans and livestock, including leptospirosis, salmomellosis, toxoplasmosis, cryptosporidiosis, rat bite fevers and many additional infections. These diseases are often spread by the faeces and urine with which they contaminate their environment as well as fleas that they usually carry.
ECONOMIC IMPACT. Crops damaged by this species include rice, maize, sugarcane, coconut, cacao, pineapple, and root crops.
LESSER BANDICOOT RAT (Bandicota bengalensis)
APPEARANCE:
A medium sized rat weighing typically up to 300 or 400gms when adult, it is slightly smaller than the Norway rat. It is stocky with a distinctly blunt or rounded muzzle and slightly upturned snout. The general dorsal fur is dark brown and ventrally, light to dark grey. Belly fur is pale grey tipped with cream. The tail is usually 20 – 30mm shorter than the head-body length (typically 25cm – similar to the Norway rat) and is dark above and below. The upper incisors project slightly forward.
BEHAVIOUR AND DIET:
It is largely terrestrial and occupies communal burrows and activity may therefore be confused with the Norway rat that occupies similar habitats and behaves in a similar manner. They generally feed on agricultural crops such as grain, maize and rice. They often live in village houses and are particularly aggressive when approached.
REPRODUCTION:
Female can have litters of 10 – 12 pups and can have up to 10 litters a year.
VISUAL SIGHTINGS. Sightings of live or dead rodents clearly indicate rodent activity. Live sightings, especially during the day, can point to nest disturbance or possibly an infestation, the latter which can sometimes lead rats to forage during the day, when there is less competition for food.
BURROWS / NESTS. Aggressive burrowers and burrows can be found under wooden structures and under piles of rubbish. Nests can additionally be found under houses and in roof spaces and are often detectable from visual evidence of shredded materials, such as newspapers and cardboard.
DROPPINGS. 10 to 14 mm in length with pointed ends (distinctive from Norway rat droppings, which are 18 to 20mm and capsule shaped).
DISEASE TRANSMITTERS. Lesser Bandicout rats have been shown to carry a very wide range of diseases that can infect humans and livestock, including leptospirosis, salmomellosis, toxoplasmosis, cryptosporidiosis, rat bite fevers and many additional infections. These diseases are often spread by the faeces and urine with which they contaminate their environment as well as fleas that they usually carry.
ECONOMIC IMPACT. Damage to buildings and structures can be serious and crop losses in agricultural areas can be severe.