What are Rats and Mice and how to get rid of them
Rats and mice are prolific breeders and if left uncontrolled can quickly develop into plague proportions. High reproductive rate, the ability to survive on a wide range of food sources and ease of travel throughout their environment, contributes to their astounding success.
Rats and mice can carry parasites, such as fleas and ticks, and diseases such as plagues, leptospirosis and typhus fever, some of which can be transmitted to humans, pets and livestock. Transmission is often caused by rat and mouse scratches and bites, or by coming into contact with their saliva, faeces and urine. Contamination and wastage of human food, pet food and bird seed is attributed to the parasites, diseases and other germs brought in by rats and mice.
Rats and mice can cause serious damage to possessions and property from gnawing on building materials, structures and wiring; producing stains, foul-smelling odours and mess; and feeding on crops, garden plants and gardening products.
Given the serious risks and extensive damage, it’s important to prevent, control and monitor for rats and mice in and around the house and garden.
Rats and mice are small rodent mammals which are distinguished by perpetually growing chisel-like front teeth. One pair lies in the upper jaw, while the other pair is in the lower jaw. The Black Rat, Brown Rat and House Mouse all have yellowing enamel on their front teeth and generally live in small to large groups.
- Black Rat or Roof Rat (Rattus rattus) is a medium sized rat. Body is slender and 350 mm to 460 mm in length, nose to tail. The coat is silky smooth and is light brown or charcoal grey on the back, with a slightly lighter coloured belly. The head is long with a rounded face, pointed nose and long whiskers. Eyes are large. Ears are prominent, large, thin and hairless. Tail is similar colour to the upper coat, hairless, scaly and longer than the rest of the body (185mm to 255 mm). Although it is most active at night, it can be seen during the day and is unafraid of humans. An accomplished climber, it disfavours water and swimming, and prefers to stay near to the nest when finding food.
- Brown Rat, Norway Rat or Water Rat (Rattus norvegicus) is a large sized rat. Body is stocky and 330 mm to 470 mm in length, nose to tail. The coat is coarse and is grey-brown, sometimes black, on the back and sides, with a white to grey belly. The head is long with a stunted nose and mouth (muzzle), a straight face and long whiskers. Eyes are small. Ears are close together, set into the head, small and hairless. The tail is scaly, hairless and shorter than the rest of the body (150 mm to 215 mm). It is mostly active in the early evening and at night. They are excellent swimmers and travel long distances from the nest to find food.
- House Mouse (Mus musculus) body is rounded and 135 mm to 200 mm in length, nose to tail. The coat is soft and is light-brown to black on the back with a white to light yellowish-brown belly. The nose is pointed with long whiskers. Eyes are black, large, prominent and bulging. Ears are large, rounded and generally naked. The tail is slender, generally hairless with circular rows of scales and is approximately the same length as the rest of the body (75 mm to 100 mm). Although they are good climbers, jumpers and swimmers, they prefer to stay close to their nest area.
- Black Rat (Rattus rattus) lives for about 2 years. After mating, females gestate for 22 days and give birth to a litter of 5 to 12 live young. Young are fed on milk for up to 28 days and reach sexual maturity within 4 months. Females may have up to 6 litters per year and produce a subsequent litter within 27 days of their previous litter.
- Brown Rat (Rattus norvegicus) lives for about 2 years. After mating, females gestate for up to 24 days and give birth to a litter of 6 to 14 live young. Females can lay up to 7 litters per year. Young are fed on milk for up to 28 days and reach sexual maturity within 4 months.
- House Mouse (Mus musculus) lives for about 1.5 years. After mating, females gestate for up to 21 days and give birth to a litter of 3 to 12 live young. Females can lay up to 14 litters per year. Young are fed on milk for up to 23 days and reach sexual maturity within 5 to 7 weeks.
Rats and mice prefer warm, dry, sheltered and quiet areas with access to food and water. They are generally most active during the night, although they may also be seen during the day.
Rats and mice can be found in the home and garden at anytime of year, however they are especially known for entering indoor areas in autumn and winter to escape the cold.
Rats and mice can be found in:
- Urban areas, farmlands and natural areas such as bushlands and coastal regions.
- Rooms: in any room in the house, especially kitchen, bathroom, laundry, garage and shed.
- Other areas inside the house: in any area of the house such as the roof, ceiling, in the wall cavity, under the floor and under the house.
- Under or inside any item in the house such as machinery, appliances, furniture, boxes, bathtubs, cupboards, pianos and drum kits.
- Outdoors: in the rubbish and compost bin; in debris such as piles of wood and rubbish; in trees; in dense vegetation such as long grass and thick shrubs; in sewers and pipes; and in animal houses such as chicken coops and kennels.
Rats and mice are omnivores and feed on a wide variety of animal and plant material such as:
- Human food: including cooked and uncooked foods; decomposing food; food spills and crumbs; food waste.
- Pet food and bird seed.
- Crops such as roots, tubers, fruits, vegetables, nuts, and grains.
- Eggs in chicken coops and bird nests.
- Snails, insects, spiders and small animals such as skinks, fish, tadpoles, frogs, young birds and rabbits.
- Organic waste in compost and rubbish bins.
- Organic fertilisers such as blood-and-bone.
- Fresh meat and carrion (long dead animals.)
Birds, reptiles, other rats and mice, dogs, cats, foxes, parasites and diseases.