Types of Rodents
Rodents are responsible for spreading a range of diseases, the plague or “black death” which is transferred to humans by flea bites being the most notorious. But of course, they also contaminate food with their urine and droppings, which also transfer disease. What is less well known is that they are a major cause of house fires as they gnaw through electrical cabling.
With their high rates of reproduction, once rodents set up home in your house a serious problem can develop quite quickly. Here are the three most common types of rodents we find in Newcastle and the Hunter Valley.
Black Rat
Also known as the roof rat, for their ability to climb up and live in trees roof voids. Latin name: Rattus rattus. This is the most common type of pest rat in Australia.
Appearance and characteristics
Sleek black / brown coat with a pale grey to white underside (they are not always black). They have large ears, big eyes, a pointed snout and long thin tail that is longer than its body. Smaller than the brown rat, adult black rats measure between 16-24cm in length and weigh an average of 150-200g.
Lifecycle
Female black rats can produce 3-6 litters a year with 5-10 pups. The gestation period lasts for only 3 weeks and the pups take around 12-16 weeks to reach sexual maturity. Their average lifespan is one year.
Habitat
Black rats are the most common pest rat found in Australia and is common in both agricultural and urban areas. They have great climbing skills and are often found in the roofs of commercial and residential buildings. They make nests out of soft materials such as grass, paper and insulation. Roof rats are neophobic which means they’re afraid of new things. Our pest technicians take this into account when designing a rodent control program as they often won’t take rodent bait immediately.
Brown Rat
Also known as the Norway rat or sewer rat. Latin name: Rattus norvegicus.
Appearance and characteristics
Brown rats have a coarse brown or dark grey coat, with a lighter grey underside coat (they aren’t always brown!). They are the largest pest rodent and have short ears, small eyes, a slanted, blunt snout and a thick tail that’s usually shorter than the body. Relative to other types of rodents, brown rats are very aggressive, so they are often spotted with damaged tails and ears.
Lifecycle
Female brown rats will have 3-6 litters a year, producing 7-8 young per litter. Brown rats have a gestation period of only 3 weeks and the pups only take 10-12 weeks to reach sexual maturity. The average lifespan is 2 years.
Habitat
Found in sewers, residential and commercial areas and farm buildings. Brown rats will commonly make burrows outside buildings and come inside to find food. Brown rats make nests out of soft materials such as grass, paper and insulation. Like the roof rat, the Norway rat is also neophobic which means they often won’t eat rodent bait for a couple of days until they get used to it. They also eat a lot of bait and have a colony hierarchy, so our pest technicians carefully consider the amount of bait we used and where to place it.
House Mouse
House mice are prolific breeders and always found in close association with humans, anywhere where there is food, both in residential and rural (agricultural) areas. Latin name: Mus musculus.
Appearance and characteristics
The house mouse is a small rodent with a short light to dark brown coat, with virtually hairless feet, ears and tail. The tail is about the same length as its body. They also have big eyes and a pointed snout. House mice are around 7-10cm in length, with a 5-10cm long tail and weigh about 10-30g.
Lifecycle
Female house mice have around 7-8 litters per year, producing 4-16 pups each. The gestation period only lasts for 3 weeks, and pups reach sexual maturity within 8-12 weeks. House mice live for an average of 12-18 months.
Habitat
House mice are mostly found inhabiting commercial, agricultural and residential buildings. Mice do not travel far from their nesting site to their food source and will happily nest in wall voids and furniture. Although they are excellent climbers, they prefer to live at ground level and will dig burrows outside, especially when there are large numbers of mice and a lack of indoor nesting locations, as happens during a mouse plague. Mice are very inquisitive and eat from lots of different locations. They are generally easy to control, although it is important to place enough bait in enough locations for the size of the infestation.
Native animals that can be confused with rodents
There are a number of native animals that are sometimes confused with the pest rats, including some native rodents, antechinus and possums. Check out our blog on rodents and native animals that enter homes.