Rats are some of the most troublesome and damaging rodents in the Malaysia. They eat and contaminate food, damage structures and property, and transmit parasites and diseases to other animals and humans. Rats live and thrive in a wide variety of climates and conditions and are often found in and around homes and other buildings, on farms, and in gardens and open fields.
|Characteristic||Roof Rat||Norway Rat|
|General Appereance||Sleek, agile||Large, robust|
|Color of Belly||Gray to white||Mostly grey|
|Body Weight||5 to 10 ounces||7 to 18 ounces|
|Tail||Extends at least to snout, uniformly dark with fine scales||Shorter than body, dark above and pale below, scaly|
|Head||Pointed muzzle||Blunt muzzle|
|Ears||Long enough to reach eyes if folded over||Don’t reach eyes|
People don’t often see rats, but signs of their presence are easy to detect. In California, the most troublesome rats are two introduced species, the roof rat and the Norway rat. It’s important to know which species of rat is present in order to choose effective control strategies.
Biology and Life Cycle
Rats, like house mice, are active mostly at night. They have poor eyesight, but they make up for this with their keen senses of hearing, smell, taste, and touch. Rats constantly explore and learn, memorizing the locations of pathways, obstacles, food and water, shelter, and features of their environment. They quickly detect and tend to avoid new objects and novel foods. Thus, they often avoid traps and baits for several days or more following their initial placement. While both species exhibit this avoidance of new objects, this neophobia is usually more pronounced in roof rats than in Norway rats.
Both Norway and roof rats can gain entry to structures by gnawing, climbing, jumping, or swimming through sewers and entering through toilets or broken drains. While Norway rats are more powerful swimmers, roof rats are more agile and are better climbers.
Norway and roof rats don’t get along. The Norway rat is larger and the more dominant species; it will kill a roof rat in a fight. When the two species occupy the same building, Norway rats may dominate the basement and ground floors, with roof rats occupying the attic or second and third floors. Contrary to some conceptions, the two species can’t interbreed. Both species can share some of the same food resources but don’t feed side by side. Rats can grab food and carry it off to feed elsewhere.
Rats of either species, especially young rats, can squeeze beneath a door with only a 1/2-inch gap. If the door is made of wood, the rat might gnaw to enlarge the gap, but this might not be necessary.
Rats eat and contaminate foodstuffs and animal feed. They also damage containers and packaging materials in which foods and feed are stored. Both rat species cause problems by gnawing on electrical wires and wooden structures such as doors, ledges, corners, and wall material, and they tear up insulation in walls and ceilings for nesting.
Norway rats can undermine building foundations and slabs with their burrowing activities and can gnaw on all types of materials, including soft metals such as copper and lead, as well as plastic and wood. If roof rats are living in the attic of a residence, they can cause considerable damage with their gnawing and nest-building activities. They also damage garden crops and ornamental plantings.
Among the diseases rats can transmit to humans or livestock are murine typhus, leptospirosis, salmonellosis (food poisoning), and ratbite fever.