Dealing With Rats & Mice

Mice

The most common mouse to be found inside your home is the house mouse. House mice have actually evolved to live in close contact to humans. In many places including Southern Ontario they are rarely able to survive the winter outdoors. Their total length including the tail is about 110 – 180mm in length with the tail being about the same length as the body and weigh less than 28 grams. The house mouse is medium grey in colour and is often confused with the deer mouse which also occasionally enters buildings. The deer mouse can be distinguished from the house mouse by its much larger eyes and ears and has a white under belly which clearly differs from the colour on its back. The house mouse’s belly is only slightly lighter in colour than its back.

Mouse Behaviour

Mice are bold and accepting of new objects in their environment. They are very curious and will rapidly explore a new environment roaming over every inch of their territory. The size of their territory varies depending on food sources but may be as small as 3 or 4 meters across. Mice tend to nibble small amounts of many food sources which increase damage and loss. They have an excellent sense of smell and hearing and they use their long whiskers in much the same way as a blind person’s cane, tapping everything in front of them as they move. Mice are also excellent climbers, swimmers and jumpers. Mice will eat many times a day and,will eat just about anything that humans eat. They are generally nocturnal but daytime sightings may be a sign of a larger population.

Life Cycle of Mice

Mice typically live about 12 months and reproduce year round depending on availability of food and shelter. They are capable of breeding at 3 months of age and will have about 4 to 6 litters a year consisting of 4 to 8 pups. Females will become sexually mature at 3 months and start having litters of their own within another month. Populations may grow very quickly when they have favourable conditions.

Signs you might have Mice

Other than seeing a mouse dart along the edge of a room, the most common sign of mice are droppings. Droppings are black, 3-6mm in length, rod shaped and pointed at each end. They are generally found close to the wall and behind furniture. The cupboard under the sink in the kitchen is a common place to find droppings . Another indication of mice is damaged goods. Nibbled bread or other food items in the kitchen may the first sign or bathroom soap or sometimes candles tucked away in a drawer. There may be small holes at the bottom edge of baseboards which are also common. Rub marks from oils on hair may be occasionally seen along passageways.

Rats

Mississauga Pest Control Services deals with rat problems on a daily basis. Rats are sometimes more difficult to control than mice because of their extremely cautious nature.Although roof rats are common in many areas of North America they are virtually unknown in Ontario. The Norway rat is the only species of rat commonly found in Southern Ontario. It is not known why this species is named the Norway rat as it did not originate from Norway. It weighs between 200 and 500 grams and varies in colour from light brown to red to grey with usually a lighter under belly. The length of the head and body is between 20 to27cm, its tail is hairless and slightly shorter than the body. This species is found all over the world, usually close to humans.

Signs you might have Mice

Other than seeing a mouse dart along the edge of a room, the most common sign of mice are droppings. Droppings are black, 3-6mm in length, rod shaped and pointed at each end. They are generally found close to the wall and behind furniture. The cupboard under the sink in the kitchen is a common place to find droppings . Another indication of mice is damaged goods. Nibbled bread or other food items in the kitchen may the first sign or bathroom soap or sometimes candles tucked away in a drawer. There may be small holes at the bottom edge of baseboards which are also common. Rub marks from oils on hair may be occasionally seen along passageways.

Norway Rat Behaviour

Norway rats are intelligent and very wary, sometimes spending a week cautiously observing areas of their territory before venturing into them. New and unfamiliar objects scare them and they will not touch or eat new food sources encountered for days or weeks. Norway rats are not good climbers and are usually found at or below ground level. If you are hearing an animal in your attic, it’s unlikely to be a rat in Ontario. They are ground dwelling and will dig extensive burrows reaching down about 1 ½ m.They gnaw through plastic garbage cans or drywall easily and given time will even gnaw through concrete. Generally Norway rats live outside but they will try to gain access into homes and buildings during cooler weather. They tend to be nocturnal but if a population grows, rats will be active during the day as well. Rats may range anywhere from 10 – 20m from their den site and up to 500m in search of food. They are social with a pack usually consisting of 1 male and 5 to 15 females however where food is plentiful and populations expand, the territorial hierarchy will tend to break down. Rats like to build their den sites underground but inside walls, ceilings or under a pile of refuse is also a common place to find them.

Life Cycle of Rats

Norway rats have 5 to 6 litters per year with each litter having about 8 to 10 pups. The young are sexually mature within 2 ½ months and gestation is 22 days. Average life span in the wild is less than 12 months.Norway Rat Behaviour

Signs you might have Rats

Probably the most common indication of rats inside is sounds such as gnawing, running, scratching and squeaks. Droppings are often present although rats tend to defecate in places more hidden than mice like underneath shelves and inside walls. Droppings are black, rod shaped, tapered at the ends and about 1 – 2cm long and about 5mm thick. Another common sign of rats is finding food that has been gnawed or damaged. Sometimes tracks can be seen. In the snow or on dusty surfaces footprints have a telltale thin line running through them where the tail drags. Outside burrows may be found along the foundation of buildings or under low shrubs. Rat holes are on average 8cm wide and have a small pile of dirt at the entrance. The hole usually goes down at a 45 degree angle. There are usually 2 or more entrances to the burrow system.

What diseases do rats transmit to people?

Norway rats are known to transmit a vast array of bacteria and parasites to humans including: Murine Typhus, Leptospirosis, Hantavirus, Hepatitis E, Tapeworm, Listeriosis and Salmonella to name just a few. In studies done on wild rat populations the presence of bacteria, viruses and parasites vary depending on the location however infection rates are sometimes as high as 90% in some populations tested.

What can I do to prevent an infestation of Norway rats?

Rats like to remain hidden where ever possible. Piles of refuse like old skids around industrial areas or stacks of firewood and ground cover close to a house give them places to hide. Long grass is a good hiding place as well. Maintaining a 1 m barrier where there are no plants or long grass around your house or building will help to prevent rats from crossing this no man’s land to gain entry. Look for holes in the foundation close to ground level; the size of a quarter and larger. Hardware fabric or ¼ inch welded wire mesh is best for sealing holes. Inside your home or office make sure there are no crumbs available behind the stove or other hard to clean areas. Dry goods should be stored in metal containers for rats as they are capable of gnawing through anything else. Keep storage areas free of clutter and the lowest shelf on a rack should be 8 inches from the ground to allow for as few hiding places as possible.

Which repellents work to keep rats away?

There are no chemical repellents for sale that have much, if any effect on rats. Our experience has been the same with sonic deterrents that emit a sound too high to be detected by human ears that are supposed to drive rats and mice away. Neither chemical repellents nor sonic deterrents work well to keep rats away.

How do you exterminate rats and mice?

We use bait, snap traps and one way doors on rats. We generally do not use one way doors on mice since they may never leave your building once they have entered and they may also have many different points of entry. We also provide complete exclusion services which will achieve long term results. We recommend exclusion where infestations are constantly recurring.

Ready to deal with your rat or mice issue?

Let the experts at Mississauga Pest & Wildlife Control Services at 905-270-1916 or 1-888-390-PEST(7378)), as one of our trained, experienced professionals will be able to determine how we can help with your rat or mice issue.

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