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Rattus spp. and Mus domesticus
Rats and mice are very destructive pests; they damage property and possessions and contaminate food. Having rats and mice in the home or garden can pose a risk to human and pet physical health. Rodents are also predators of many native species. The most common rat and mouse species in NZ are the Ship Rat (Rattus rattus), Norway Rat (Rattus norvegicus) and House Mouse (Mus musculus).
To ensure rats and mice are quickly and effectively controlled around your home, it's best to take a holistic approach. It's crucial to control rats and mice via the use of baits or traps, or a combination of both. It's essential to remove all easy food and water sources. Where possible, stop rats and mice from physically entering your house, and make shelter and nesting areas less hospitable to them.
RATSAK bait products should be carefully chosen for the situation. Consider the suitability of the product based on the presence of children and pets, and the location and environment.
Top RATSAK Bait Tips:
Great RATSAK Bait Products:
RATSAK trap products are suitable for most areas, when used safely and according to label instructions.
Top RATSAK Trap Tips:
Recommended RATSAK Trap Products:
Your pets safety is our priority. For information relating to potential or suspected poisoning through the use (or misuse) of our products in New Zealand, please contact our Emergency Response Service (ERS) on 0800 220 770 (24 hours).
Rats and mice are prolific breeders and if left uncontrolled, can quickly develop into plague proportions. A high rate of reproduction, the ability to survive on a wide range of food and ability to move freely through their environments all contribute to their astounding success.
Rats and mice can carry parasites, such as fleas and ticks, and diseases caused by viral or bacterial pathogens, like leptospirosis or mycoplasma (some of which can be transmitted to humans, pets and livestock). Transmission can be caused by scratches and bites, or by coming into contact with rodent saliva, faeces or urine. Contact from rodents causes contamination and wastage of human food, pet food and bird seed.
Rats and mice can cause serious damage to 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.
Peak rat season is from March to June, as the weather cools. Total rodent numbers correspond with breeding conditions over summer. If there's a healthy amount of food available, a female rat will produce up to 12 litters of 20 rats each. Rats live for about 2 years, on average. One pair of rats has the potential of 15,000 descendants in a year!
NZ beech and podocarp (rimu, kahikatea, mataī and totara) forests produce heavier seed crops every two or three years, commonly known as ‘masting’ years. The extra food supply provides a bonanza for mice and rats, whose numbers often explode in response. Populations can increase significantly from October to May after a 'mast'.
Rats and mice are small mammals in the Rodent genera, distinguished by their perpetually growing chisel-like front teeth. They generally live in small groups.
Ship Rat, also known as Black Rat or Common 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 a similar colour to the upper coat, hairless, scaly and longer than the rest of the body (185mm to 255 mm). Although it's most active at night, it can be seen during the day and is unafraid of humans. They are widespread in native bush and are also attracted to buildings in urban areas. An accomplished climber, so they're able to prey on NZ native bird nests. They don't like water and swimming, and prefer to stay near to their nest when finding food.
Norway Rat, AKA Brown 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 blunt 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's mostly active in the early evening and at night. They are excellent swimmers and travel long distances from the nest to find food. They're devastating to native species, being big enough to prey on ground-dwelling birds & eggs, reptiles & invertebrates. They are often found in urban areas and especially around pig sties, chicken runs, watercourses or ponds in rural areas.
House Mouse (Mus musculus) has a rounded body and is 135mm to 200mm 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 hairless. The tail is slender and 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. Mice are widely distributed throughout NZ (and have been caught as high as 1,300m in the Southern Alps). Mice can successfully inhabit almost any environment, especially in the presence of humans.
Kiore or Pacific Rat (Rattus exulans) was introduced into New Zealand by Māori settlers in about the 10th century. They're now much less widespread than the other two rat species, being mostly confined to the Southland region. Although Kiore do have a destructive effect on native invertebrates, they're not specifically targeted by major pest eradication programmes.
Rats and mice prefer warm, dry, sheltered and quiet areas with access to food and water. They're generally most active during the night, although they may also be seen during the day.
Rats and mice can be spotted at any time of year, but they're especially known for entering indoor areas in autumn and winter when food becomes scarce.
Rats and mice can be found in:
Rats and mice are omnivores and feed on a wide variety of animal and plant material such as:
Birds of prey, other rodents, dogs, cats, and stoats.
Often, you'll see a living (or dead) rodent, so that's a pretty obvious sign there's a problem. Other ways to ID rodents include:
Tracks, footprints and tail marks
Signs of rats and mice are sometimes confused with birds, possums, and other animals. Before setting out any baits, traps or repellents, make certain the cause has been properly identified as rodents.
Monitor regularly, checking for signs of rats and mice (see ‘What to Look Out For’ above). Making your house and property inhospitable to rodents really reduces the likelihood of future infestations and helps to get on top of a current infestation.
Remove entry points:
Remove shelter sources:
Remove food sources:
Remove water sources:
Rats and mice cause damage to plants by feeding, gnawing and burrowing. They can damage seedlings, roots, tubers, fruits, vegetables, nuts and grains. Produce may be picked up and taken away, or show bite marks, gnaw marks or small chewed holes - the whole fruit or vegetable is unlikely to be eaten. All fruits and vegetables are vulnerable to attack; thin-skinned and sweet crops are rodent favourites.