Perth Pests – Roof Rats, Norway Rats, and Other Rat Pests

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Rats are a problem in many parts of the world, and Australia is no exception. As is true throughout the globe, rats in and around Perth are an ever-present menace. While most people understand that these rodent pests can carry a variety of diseases and spread illness by contaminating food sources and homes with their urine and fecal matter, they can also damage those homes in other ways. Because of those dangers, any rat infestation should be dealt with as soon as possible.

The Main Rat Menace in Perth

Perth is not alone in suffering from an infestation of two of the most bothersome rat varieties on the planet: the roof rat and the Norway rat. Together, these two pests have become a common problem for many businesses and private homes in the region. Each presents its own challenges when it comes to preventing entry into human structures, but both damage property, create foul odors, and increase the risk of serious disease and illness for both humans and their pets.

The Roof Rat…

The roof rat – or rattus rattus – is often referred to as the black rat or the ship rat. These creatures are believed to have been introduced to Australia from Europe, having arrived on the ships of the First Fleet. There is evidence that they may have arrived in the 1600s, as the remains of black rats have been identified in the sunken remains of Dutch ships found off the coastal areas of Western Australia. In either case, they are considered a non-native invasive species, and a major pest in Perth and the surrounding environs.

Black rats reach lengths of 24 cm, have tails that are longer than their bodies, and can weigh as much as 200g. Because of their size, they are often mistaken for other small mammals like baby possums. However, they have many characteristics that make them easy to identify. Their fur is typically black, charcoal grey, or brown on the topside, and white or cream-colored on the underside. Their noses are pointed, and protrude from somewhat rounded faces that are highlighted by large, thin ears.

As their name suggests, these rats often nest in high areas. They are incredibly accomplished climbers, and often gain access to rooftops from overhanging tree branches and other structures near a home or commercial building. Once there, they nest, breed, urinate, defecate, and gnaw on just about anything they can find. Their favorite foods seem to be seeds, leaves, fungi, fruit, insects, and other smaller creatures – though they will also consume food that is left out for dogs, cats, chicken, cows, and other pest or farm animals. In the wild, they will eat a wide variety of grains, fruits, and even sugar cane cultivated by human farmers.

They are highly adaptive, which helps to explain their success in such a wide variety of habitats. As a result, they are found in both agricultural and rural areas, typically making their nests in elevated locations. In the cities, they are typically found in the top levels of buildings, including attics and false ceilings. In the wild, they make their homes in the trees, cliffs, and elevated rock formations – though they sometimes burrow into the ground or take up residence around fences and bodies of water.

The black rat’s most infamous characteristic – and one that has been responsible for untold millions of deaths in past centuries – is its status as a carrier of disease. Roof rats were believed to have been responsible for carrying the plague-infested Oriental rat flea that brought that disease to Europe in the 14th Century, resulting in the Black Death pandemic that experts believe killed between thirty and sixty percent of the continent’s total population.

The Norway Rat…

Meet rattus norvegicus, better known as the brown rat, sewer rat, or Norway rat. This variety of rat is one of the better known types of rats in the world, and for good reason. Though it is believed to have had its origins in China, it has spread out throughout the globe and is now present on every continent but one. Moreover, it is the main rat variety in many places on Earth, and is thus considered to be the second-most successful animal in the world – living almost everywhere humans are found.

The Norway rat’s body can grow to be as large as 25 cm in length, and its tail is roughly that same length. Adult males often weigh as much as 350g – with some domestic rats growing to be as large as 1,000g. Wild ones, however, seldom exceed 300g – which still makes them considerably heavier than their roof rat cousins.  Their fur is much courser than black rats, and is typically grey or brown in color, with lighter shades of each on their undersides. It has a blunter nose and smaller ears than a black rat, and generally has a thicker body as well.

Like black rats, these creatures can climb when necessary. They are at their best, however, when they are on the ground or in the water. These rats prefer to burrow or make nests in concealed areas on the ground. They are also highly accomplished swimmers, which is why they earned the moniker “sewer rat” – as many are often found in those damp and water-filled tunnels.

The Norway rat will almost literally eat anything it finds. The only real restrictions on their diet appear to be environmental, since they will consumer virtually any available food source. Cereals seem to be a preferred food option, but previous studies have confirmed that they seem partial to human foods such as scrambled eggs and cooked corn. They are classified as foragers, but have also been seen hunting birds, diving for mollusks, and catching small fish.

This rat can also serve as a disease carrier, and has been known to carry the pathogens that cause diseases ranging viral hemorrhagic fever to Weil’s disease and hantavirus. They can also suffer from the plague, but research seems to suggest that they themselves are not active carriers of the disease. Their ability to carry other diseases, however, makes them dangerous when living in close quarters with humans and other animals. Unfortunately, they tend to gather in large numbers wherever human dwellings are found.

Why They’re Considered Pests

Rats may actively seek out human dwellings, and they certainly have little problem making themselves right at home when they find a suitable abode, but that doesn’t mean that their companionship is something to be desired. The fact is that these are some of the most annoying and dangerous pests in the world, and infestations should be dealt with just as soon as you are made aware of a rat presence in your home, business, or other physical structure.

As noted above, rats can carry a wide range of diseases and illnesses. To make matters worse, they also carry with them various parasites that can also quickly spread throughout your home. Fleas travel from place to place nestled in the fur of rats, and can then transport themselves to your pets or other animals. Rats also bring with them ticks and lice, which can be bothersome pests in their own right.

Their damage to human habitations extends beyond the risk of illness. They also leave their droppings throughout their territory. Along with their urine deposits, these droppings can result in foul odors that can often be difficult to identify. Because of the way that they travel near to walls and baseboards, the dirt and grease that tends to gather on their bodies often leaves marks on those surfaces. There’s a reason rats are generally considered to be among the filthier animals on the planet!

The growth rate of their teeth presents another challenge for human structures. Rats tend to gnaw constantly in an effort to manage this growth. As a result, they will chew on furniture, loose floorboards, paper, food packaging, and even electrical cables. That latter tendency can result in electrical fires that can severely damage buildings and even place human life at risk. And because they are such prolific breeders, that potential damage can multiply quickly once an infestation of rats takes root in your home.

How to Detect Their Presence

Like mice, rats are nocturnal in nature and seldom seen in the daylight. They usually take great pains to avoid human contact whenever possible, so visual sightings within the home are rare at best. That does not mean, however, that you will have no way of detecting their presence if they have infested your house. There are a number of telltale signs that serve as an indication that rats have taken up residence in your building:

  • A single rat can produce 30-40 droppings each night, so a nest of these creatures often leaves unmistakable evidence of its presence. Rat droppings tend to be about the size of a single rice grain.
  • Grease marks. As discussed, rats are dirty rodents, and their fur tends to contain large concentrations of grease, dirt, and other material that creates smears and streaks on baseboards and other surfaces that they touch. The only drawback to this indication is that, in the absence of regular baseboard cleaning, these smears are sometimes indications of old infestations.
  • The existence of rat burrows on your property can be an indication that rats have nested nearby. In the wild, some rats dig complex burrow systems under decks, in sheds and garages, or even around wood piles that serve as shelter and nesting locations.
  • It is rarer to find nests that are readily visible, but sometimes rats will build them behind appliances or other areas of the kitchen or pantry.
  • Chewing damage. Rats chew constantly, so if they have infested your home then you will likely see evidence of chewing at some time or another. This can include shredded paper that they may destroy to create material for their nests, chewed cardboard boxes, gnaw marks on furniture, or other visible signs of chewing activity.
  • Paw prints. Yes, their feet are tiny and it might seem odd to look for paw prints on the floor or counters. If you have areas of the home that are outside your normal cleaning range, though, you can sometimes see tracks in the dust on the floor. If you suspect rat activity and want to know for certain, try sprinkling flour or baby powder on the floor before you go to sleep and then look for fresh tracks in the morning.
  • Like mice, rats can be noisy creatures. Black rats will typically make scratching noises at night in the upper levels of your home. The Norway rat tends to stick to the lower levels, and can usually be heard either scampering about or grinding its teeth.

Dealing with Infestation

Of course, the big question every homeowner or business owner must confront when they suspect that rats are present is how to get rid of them. Your best immediate option is to contact a professional pest control expert to ensure that your rat infestation is dealt with promptly. After an initial inspection to confirm that these creatures are present, that expert will offer one of two main removal options to correct the problem: baiting or trapping.

Baiting Methods

Baiting methods involve the use of poison bait in areas that rats are suspected of frequenting. The idea behind this removal strategy is that the rats will eat the poisoned food and then die. Bait of this kind can be an effective way to eliminate any rat problem, but care must be taken to ensure that poisons are not placed where children or pets can reach them, because those poisons are toxic to humans and other animals as well.

Trapping Systems

There are times when trapping can be effective as well, using either capture boxes or the old snap-back traps. When baited, these traps lure rats in and then prevent their escape. Their drawback is that rats are naturally suspicious creatures, and wary of new objects they encounter in their territory. In most cases, however, the rat just needs time to get accustomed to the object as part of its natural surroundings. As a result, traps generally take a few days to work.

Naturally, the best way to deal with rat infestation is to prevent one from taking root in the first place. Keep tree branches cut back away from your home, eliminate waste from your yard, and make sure that there are no cracks, holes, or other easy entry points on the outside of the house. Since even those methods are far from foolproof, it is important to be vigilant to the signs of infestation and call for professional help as soon as a problem is identified.