Control and Prevention of Rats and Mice
Dr. Scott Lingren, BCE
Venus PestCompany
The most commonly encountered rodents in homes are the house mouse, Norway rat, and roof rat. All three of these pests were introduced to the United States from other countries. The house mouse originated in central Asia and arrived in North America aboard the ships of early trade merchants and immigrants. The Norway rat came to North America in around 1775 with European settlers and trading ships. The roof rat, like the house mouse, originated in Asia. Roof rats came to North America in the 1600’s along with the Jamestown settlers. Rats can be distinguished from mice mainly by their size. Rats are typically 7-10 inches long, while mice are only 2-3 ½ inches long. Rats have tails that are an additional 6-10 inches long, while mice have tails that are only 3-4 inches long. Rats and mice can also be distinguished by their droppings. Mouse droppings are 1/8-1/4 inch long and usually pointed on at least one end. Rat droppings are ½-1 inch long and usually blunt on one end.
While these pests are not native to the United States, they haven’t had a problem making themselves at home. In the United States, over $120 million are spent each year on rodent control. Rodents are considered pests for several reasons. They can damage our homes by gnawing on wood, pipes or electrical wiring. They leave droppings everywhere and eat our food. Most importantly, they are unsanitary and are involved in the transmission of many diseases.
Large numbers of rodents can not develop without large amounts of food. This means that sanitation of food and garbage inside and around your home is a very important step in controlling rodent populations. Rats and mice will eat almost any kind of food, but they often prefer grains and cereals. Pet food, if left out, can provide a source of food for rodents. Outdoors, garbage cans should be sealed to prevent rodents from scavenging for food. Indoors, liners should be used in garbage containers to prevent buildup of possible rodent food in the trash container. With enough food, a female rat or mouse can produce 20-35 new rats or mice per year.
Rodents also need shelter. Removing rodent habitats will decrease the chance of getting a rodent problem. Indoors, try to keep clutter to a minimum. This will prevent rodent nests from going unnoticed. Outdoors, shrubs and grass should be kept trimmed, especially near the house. Junk piles should be removed and wood piles should be kept as far away from the house as possible.
Rodent control for Venus Pest Company consists of three steps. The first step is exclusion. Exclusion means that cracks and holes in your home are sealed to prevent rodent entry. Have you ever had a rodent problem and tried trapping? It works great, but it seems like you can trap and trap and trap and the problem never really goes away, or it reoccurs the next year. That is because your house is wide open for rodent entry, and there are plenty of rodents outside wanting to come in. With our approach, openings greater than ¼ inch should are sealed. Common problem areas are where utility lines or pipes enter the house. Copper wool or hardware cloth is used for these types of openings and may be used in combination with expanding foam. Holes that require special trades such as carpentry cannot be corrected by Venus Pest Company, but we will identify those holes and suggest a company to repair them.
The second step is the use of poison bait. In most cases, bait is only used outside. Also, the bait is placed in tamper-proof containers. We typically use a bromethalin-containing bait. This has the lowest mammalian toxicity (dogs and cats) and has the lowest risk for secondary poisoning (dog or cat eating poisoned rodent). We don’t use the bait inside because we don’t want rodents dying inside. The story that there is some bait that makes them go outside for water is an Urban Legend.
Finally, we use traps inside. For rats, we use snap traps. If the traps are in an exposed area, we usually place them inside tamper-proof containers. For mice, we prefer to use repeat traps like the PolyCat. These traps don’t snap, so they are not a hazard to kids or pets. Our typical rodent service includes 3-4 visits to inspect, install, and monitor the traps and bait stations. If you want to try doing it yourself, most of the products we use are available on our website: www.venuspest.com.
