Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. “True rats” are members of the genus Rattus, the most important of which to humans are the black rats, Rattus rattus, and the brown rats, Rattus norvegicus. Rats are typically distinguished from mice by their size. Rats nest in high places such as trees, but sometimes in burrows under plants. Indoors, they nest in high places in structures, but sometimes in basements, sewers, or under buildings. Rats eat almost anything, but they prefer fruit, vegetables, and cereal products. Rats gnaw, eat stored food, and transmit disease by droppings, urine, bites, and the fleas as well as mites in their fur.
Here are the commonly found species in Malaysia:
The brown rat, also referred to as common rat, street rat, sewer rat, Norway rat, Norwegian rat, or wharf rat (Rattus norvegicus) is one of the best known and most common rats. This species of rats have widely spread throughout the world, making it by at least this particular definition the most successful mammal on the planet after humans. The brown rat is nocturnal and is a good swimmer, both on the surface and underwater. It has quite poor vision but it makes up for this with its acute senses of smell, touch, taste and hearing. Brown rats are capable of producing ultrasonic vocalizations. Adult rats will emit ultrasonic vocalizations in response to predators or perceived danger. The brown rat typically lives in underground burrows that have one or more exits and rooms for nesting and for food storage. Their regular pathways are scent-marked with urine. The brown rat can breed throughout the year if conditions are suitable, with a female producing up to five litters a year. Maximum life span of an adult is up to three years.
Generally smaller than the brown rat (Rattus norvegicus), the black rat is typically a uniform black to tawny brown colour, with lighter underparts. The tail, which is longer than the head and body, is hairless, and is used for balance. The black rat is nocturnal, although it may become more active in the day in undisturbed areas. They prefer to live in roofs, cavity walls, trees, scrapes or burrows around farms, making nests of shredded materials. Black rats are very closely associated with humans, common in urban areas, and are very agile climbers. Like Norway rats, roof rats can swim and may use sewer systems to disperse to new areas. Roof rats are omnivores (plant- and animal-eating). These rats will also feed on stored food and livestock feed and will contaminate much more than they actually eat. Breeding takes place between March and November. Three to five litters can be produced in a year, each litter containing of an average of seven pups.
The house mouse (Mus musculus) is a small mammal of the order Rodentia, characteristically having a pointed snout, small rounded ears, and a long naked or almost hairless tail. house mouse mainly lives in association with humans. Mice are good jumpers, climbers, and swimmers. Mice are territorial, and one dominant male usually lives together with several females and young. House mice usually live in proximity to humans, in or around houses or fields. House mice primarily feed on plant matter, butare omnivorous. They will eat their own feces to acquire nutrients produced by bacteria in their intestines.