Rat Control in Maryland

What do rats look like?

The photo of the Norway Rat below was taken at Baltimore, Maryland home.

Norway Rats have two large upper incisor teeth directly beneath their blunt nose and small ears that hug close to their head. Their colors come in a silverish gray or reddish brown or grayish brown color. This stocky rat has a thick body between 7 and 10 inches long and weighting around 10 to 16 ounces making them slightly larger than the Roof Rat. Their thin almost completely hairless tail in typically 6 to 8 inches. Norway Rats are predominately nocturnal so their blackish eyes appear to slightly protrude from their head which helps them see better at night. However, they do have poor eye sight and are color blind so they rely mostly on their excellent hearing and their superior sense of smell.

Roof Rats are a dark brown to blackish color with a body and tail length of 13” to 18”. Their narrow body is a bit smaller than the Norway Rat and they weigh between 5 to 9 ounces. Their almost hairless ears are a bit larger than the Norway Rat. The tail is almost hairless as well.

What species of rats are found in the United States?

The three species of rats found in the United States are the Woodrat, Roof Rat, and the Norway Rat. Norway Rats are also known as Brown Rats, Sewer Rats, Gray Rats, and Wharf Rats. They are the most abundant species throughout cities and towns across the United States. Norway Rats and Roof Rats are not native to the United States but arrived on ships centuries ago.

Where do rats live and what habitat do they prefer?

Norway Rats always live in close range to humans as they have come to rely on the endless supply of food humans provide for them. This intelligent rodent likes to play it safe and usually stays within 100 to 150 feet diameter around their burrow so they can quickly retreat underground if a predator gets to close. They always us the same path and become alarmed when any new objects appears within their path.

They are not good climbers like other species of rats and prefer to live in burrows underground. These burrows are cleverly designed with chambers for specific needs. One chamber within the burrow can be used for food storage and one chamber for each female to nest in. Just like humans remodeling homes a Norway Rats will alter or re-design or add on to their burrow. The restructure of a burrow is often done to accommodate more rats. Burrows are usually around 12 to 18 inches below the ground level and the entrance hole into the burrow is about 2 to 4 inches in diameter and is usually covered with grass or a little dirt to disguise the entrance. At first there is only 1 entry hole with about a 2 to 3 foot long tunnel leading to a nest cavity that has fine grass clippings, paper, pieces of cloth and other soft materials for the new born babies to lay in. As the colony grows the burrow gets larger and more entry / exit holes are added.

The Norway Rats that dig burrows underground usually choose to do so alongside the foundation of a home or building or under slabs of concrete or concrete walkways or under concrete steps or under sheds and outbuildings or any other man-made structure that offers structural support for their burrow. Their burrows are always near a food source such as a dumpster, garbage cans, near pet food bowls in the yard or bird feeder.

The nesting site of Norway Rats that live inside of homes or buildings are usually in wall cavities, attics, crawl spaces, basements, drains and sewers, in floor voids, in or under or behind kitchen cabinets and appliances. Female Norway Rats will build nest from soft materials that she finds in the house or building. She may construct the nest from pieces of shredded up carpet, cardboard, insulation, paper, clothing, or even stuffed animals. Nesting sites in homes or buildings are usually in very close proximity to the food source such as pet food and water bowls.

The Norway Rat burrow in the photo below was taken at a restaurant in Annapolis, Maryland. Rats had dug a tunnel down alongside the foundation and created an elaborate system of tunnels and chambers under the concrete basement floor. These rats had dug so much dirt out from under the floor it caused the concrete floor to crack and collapse. The restaurant owners hired several different pest control companies in attempt to get rid of the rat problem but none of the companies were able to resolve their rat infestation. After three years of continuous rats and unsuccessful contracts with pest control companies the restaurant owners decided to contact Mid-Atlantic Wildlife Control. After Mid-Atlantic Wildlife Control’s rat expert inspected the property and executed an advanced rat eradication method the rat population was wiped out within a week. Mid-Atlantic Wildlife Control also sealed up all burrows and holes to prevent other pest from moving in.

In the photo below you can see a hole in the ground directly under the bird feeder. This homeowner enjoys feeding the birds however she was also unintentionally attracting rats to her property as well. The homeowner was surprised to find this burrow one morning while filling the bird feeder. As the birds eat from the feeder they drop a great deal of seeds on the ground. Rats have taken advantage of the abundant supply of bird seed and decided to make their selves a home under the bird feeder and under this homeowner’s deck. The homeowner attempted to take care of this problem on her own but after 4 weeks she quickly realized she had become over run with rats and had to call a pest control company to resolve the problem before the rats got into her home.

Below is a diagram of a Norway Rat burrow. This diagram helps you better understand how the Norway Rat lives and the functionality of their burrow. Different chambers within the burrow are used for different things. Some chambers are used to raise young and some are used for sleeping and some for defecating.

Roof Rats prefer to nest up off the ground in trees, woodpiles, upper levels of buildings, in attics, in trees, in shrubs and piles of debris. In fact, they spend 90% of their entire life 4 feet or higher off the ground. During the hot summer months of June, July and August Roof Rats sometime prefer to nest in thick hedges and trees but from September to May when they are most active and temperatures are cooler they can be found in attics.

In urban areas it’s not uncommon to see Roof Rats crawling across powerlines from one house to another. In townhomes they will run along the interior soffit from one homes attic to another. Roof Rats will access a rooftop or attic by climbing up any rough surfaces such as stone, brick, stucco, or concrete. For safety they prefer to take the same route each and every day. Roof Rats are a nocturnal rodent and usually keep their travels within 200 or 300 feet of their nesting site. Common areas they prefer are attics, crawl spaces, in cabinets, ceilings, behind walls of the upper level of a home, pool areas, garages, and patios.

What type of damages can rats cause?

Norway Rats are rodents and like most rodents they have large front incisor teeth that never stop growing. To keep their front teeth at a manageable and comfortable length they must constantly gnaw on hard surfaces. Norway Rats that live inside homes and buildings are known to gnaw on drywall, baseboard trim, pipe, 2”x4” boards in walls, wooden doors, boxes, insulation, structural beams, clothing, and more.

The most dangerous thing rats gnaw on in homes is electrical wiring especially since an average of 35% of all homes in the United States have a rodent problem. Most of these fires were caused by rodents gnawing on electrical wires in walls and attics. Norway Rats are also known to cause water damage when they gnaw on PVC pipes. In some cases small leaks in walls or ceilings go undetected until mold problems arise.

Norway Rats like to burrow under homes and buildings causing extensive damage to the foundation. They undermine the concrete walls and flooring causing large cracks. Some homeowners have woke up to find they are not able to open the front door because their entire house has shifted do to rats burrowing under the foundation. Rats have damaged the foundation of some homes so bad the home has had to be condemned.

Norway rats will get into food that is stored in containers by chewing holes through the containers. They will defecate and urinate in the stored food rendering it useless for consumption by humans, pets and livestock. They will cause expensive damage to crops in fields before the crops are harvested, after harvest, and will the crops are being processed.

Rats cost restaurant and food warehouse owners millions of dollars each year by contaminating the food and surfaces where the food is prepared. Even the cleanest restaurants and food warehouses will battle rat problems as long as their open do to the endless supply of food.

Roof Rats are known to cause costly damages to homes and buildings. They chew holes through soffits, eaves, gable vents, ridge vents, dormer pockets, fascia boards and roof joints to gain entry into attics and crawl spaces. Once they have entered the attic they will gnaw and chew on everything in sight to keep their incisor teeth at a comfortable length. They chew on the outer cover of electrical wiring creating a fire hazard. In fact, hundreds of homes catch fire each year from roof rats gnawing on electrical wires. They also chew on support beams and roof trusses creating structural damage. Their constantly defecating and urinating on everything in their pathway especially attic insulation. Once the urine has soaked into insulation there is no getting rid of the horrific odor that comes with it. Most homeowners have to spend thousands of dollars to have the attic insulation cleaned out and new insulation installed. Roof Rats also commonly cause water damage as the rain enters through the holes they have chewed through on the roof. Water damage is also caused when Roof Rats chew on pipes to get a drink of water from inside the pipe.

What are the signs of a rat problem in a house or building?

Norway Rats are never alone. They are a nocturnal species and usually roam under the cloak of night when humans are sleeping. Many homeowners that have a small rat problem never see a rat but hear them in the walls or ceiling or they find signs of a rat problem in the house. For every one rat you see there are ten more you don’t. If you see a rodents during the day, this is a sign that the rat population in your home or on your property has overgrown the territory meaning there is not enough food or water to sustain the number of rats. If you see a rat during the day time it could also mean that its nest has been disrupted or it could mean the rat is sick. Rats that have eaten rat poison may also roam during the day.

Rats prefer to take the same path all the time and their feces is usually seen on the floor along the baseboards, in kitchen cabinets or near nesting areas. The size of the droppings varies from a ¼ inch to ¾ of an inch depending on the size of the rat. Fresh droppings are soft and will flatten like a pancake if you squeeze it between two fingers and if the droppings are old they will crumble when squeezed. Their droppings are usually a shiny blackish color depending on the food they eat and are always shaped like a capsule with two blunt ends.

Both male and female Norway Rats deposit small drops of urine on floors, the ground and objects throughout their territory. Urine marking is a form of communication. Other rats can identify another rats sex, age, social status, reproductive status, and stress level by smelling the chemicals within the urine. A rat can also tell how long ago the urine marking was left. The longer the rats are in your home the more urine markings are left behind and after a short period of time a pungent odor will overwhelm a house. Urine markings usually cannot be seen with the naked eye however a black light or UV light will allow you to see the markings.

Norway Rats must gnaw to maintain the length of their teeth. The holes they chew are 2 plus inches in diameter with rough or gagged edges. They will also gnaw on the edges of wooden structural boards, drywall, baseboards, doors, and cabinets. Other objects or materials they are known to gnaw on are cardboard, PVC pipes, plastic, insulation foam, and rolled insulation. They also gnaw on electrical wire in walls and attics causing hundreds of fires each year.

Roof Rats are a nocturnal species and can go undetected for long periods of time because they tend to stay up high in trees and attics. Most homeowners realize they have a Roof Rat infestation when they hear scratching noises coming from the attic or upper walls. Water damage on ceilings caused by holes they chewed through pipes is another indicator you may have a Roof Rat problem. Bad odor from their urine may be detected when a home is infested with Roof Rats. Signs of ½ inch long droppings with blunt end on the attic floor are another indicator of an infestation. Sightings of Roof Rats running on tree limbs or power lines close to the house is another sign you may have a Roof Rat problem. You might also find dirty looking or dark oily rub marks from their fur on surfaces along their path.

What are the mating habits of rats?

Norway Rats have different mating habits for different social structures. Norway Rats that live indoors may breed throughout the year however if they live strictly outdoors or a combination of outdoors and indoors then they may only breed in the spring summer and early fall. Some Norway Rats live inside of homes or buildings in wall cavities or in floor voids and others burrow underground and live in tunnels with chambers. The rats that burrow underground live in colonies with up to 6 females that are usually related and one non-related male. The female rats and male rat in each burrow live a polygamist life style. The male will guard the entry hole to keep other males from mating with the females in the burrow. As the number of females increase the size of the burrow increases and one male is no longer able to fend off other males. Other males will now gain entry and mate with some of the females.

At this point multiple males will mate with any female that’s in heat. Females however are more selective as to who they reproduce with and prefer to mate with the more dominate males. One female can become pregnant by multiple males at one time resulting in the offspring from the same litter being half siblings with the same mother but different fathers. Males will sometimes kill newborn rat pups so the female will go into heat quicker but when a female breeds with multiple males at once it ensures that the males won’t kill her offspring. If a large percentage of the rat population is exterminated or dies from disease in a territory then the rats that survived will dramatically increase reproduction to restore the population to what it was.

Roof Rats have most of the same mating habits as Norway Rats. They are able to mate as young as 3 months old and they do not have a mating season. They have evolved to mate in accordance with warmer temperatures. They only mate during warmer months in the northern part of their territory but mate all year long in the southern part of their territory.

The Roof Rats mating rituals start with the hierarchy. Females will mate with the most dominate males in the territory. This guarantees that the female will pass the more superior genes onto her offspring. Since the female mates with multiple males her offspring from the same litter will have different fathers. This technique will ensure that the dominate males do not kill her young when they are born. Roof Rats have a longer gestation period then Norway Rats by about two or three days.

How many young do rats have per year and how do they raise them?

Norway Rats reach sexual maturity at around 8 to 12 weeks old. Females Norway Rats can mate a day or two after they give birth to a litter and can nurse one litter while being pregnant with another. They can also go into heat about every 4 to 5 days. Females are capable of delaying giving birth up to two weeks when food is scares. Females have a short gestation period of 22 days and have an average of 4 to 7 litters of pups each year which equals out to be between 32 and 84 offspring per year. If all the females born to one female in a years’ time would successfully reproduce every cycle throughout the year the population of rats could increase by 15000 per year.

Norway Rats are born hairless with their eyes and ears closed. Rat pups feed on their mother’s milk for the first 2 ½ to 3 weeks at which time they begin eating solid foods. At 4 weeks old they are 100% independent and surviving on their own.

Roof Rats are no different than Norway Rats when it comes to quickly multiplying. After a gestation period of 21 to 23 days each female has between 3 and 5 liters per year depending on the climate and food sources available. Each litter consist of 5 to 8 pups. Their almost hairless pups are born with pink skin and their eyes and ears closed. The pups feed on mom’s milk for the first 2 or 3 weeks then solid foods are introduced. Once on solid foods the pup’s growth rate increase dramatically and their able to successfully be on their own by the time they are 3 months old.

How do rats enter homes and buildings?

It’s best to have knowledge of the architecture of a home or building to better understand how rats can enter a home or building. Rats can squeeze into a hole as small as a quarter or a ¾ inch gap. Rats have no problem getting in since holes that size are found all over the exterior of homes and buildings. If there is no pre-existing hole to enter through then they will simple find a vulnerable spot to chew and dig through.

Norway Rats commonly enter homes and buildings through crawl spaces under homes, sewage pipes, under doors, around air conditioning lines in the foundation, the sides of window air conditioners, vents, and dog doors. Most of the time they chew holes through just about any area around the ground level of the home. Although Norway Rats usually enter around the ground level they do occasionally climb up the exterior of a home and enter through drip edge, gable vents, dormer pockets, fascia boards, soffit vents, roof joints, ridge vents, and attic fans.

You can see in the photo below that Norway Rats have taken advantage of the deteriorating wood around this exterior door frame. Norway Rats easily chewed through the bottom corner of this door frame to gain entry into this homeowner’s basement. The rats were feeding on dog food and cat food that the homeowner left on the floor in the basement for his pets. The homeowner hired a rat control expert from a Frederick County pest control company to take care of this rat infestation. Because the rats were on the inside of the home the rat control expert decided not to use poisons to prevent the rats from dyeing inside the ceiling and walls and causing a terrible odor in the home so the expert strategically set 25 rat traps along the trails that the rats were using to travel throughout the home. After 3 days of trapping 12 rats were removed from the home. Traps were left set for several more days to ensure that no rats were left inside the home. The expert also used rat proof materials to repair and seal the existing entry points to prevent any additional rats from entering the home.

Roof Rats are excellent climbers and are famous for entering homes around the roof top. They will climb up any vertical porous surface that they can get their nails into such as homes with a brick, stone stucco, or concrete surface. Wooden exterior facades like cedar are no match for Roof Rats. In many cases they gain access to the roof top by climbing up trees and jumping onto the roof from over hanging tree limbs. They also climb up utility poles and run across electrical power lines to access rooftops. Tall shrubs and vines growing on the walls of the home are also used to access rooftops.

Once they have access to the rooftop they will find a vulnerable spot and chew a quarter size hole to gain entry into the attic or crawl space. Many materials like stucco, wood, plastic, sheet rock, and aluminum prove to be no match for the Roof Rats powerful large incisor teeth. The gaps between the louvers of gable vents and the fine mesh screening behind the louvers makes for an easy entry point. Soffit edges and mesh on soffit vents are no problem for Roof Rats to chew through. Other vulnerable areas where Roof Rats prefer to enter attics are roof joints, ridge vents, attic fans, drip edge, and dormer pockets. Often they don’t even need to chew a hole through because they are able to fit in many pre-existing holes around the rooftop. Smaller Roof Rats can squeeze into nickel size hole and larger ones can easily fit in quarter size holes.

What diseases do rats carry?

Rats can carry and transmit several diseases to humans, pets, and livestock causing temporary illness, permanent illness and even death in some cases. Norway Rats can carry Hemorrhagic Fever which is a virus that is rare in the United States. Hemorrhagic Fever develops within 1 or 2 weeks after exposure occurs. Symptoms include severe headaches, abdominal pain, back pain, redness of the eyes, a rash, fever, nausea, chills, blurred vision, low blood pressure, vascular leakage, kidney failure, and fluid retention. It is spread by direct contact with the rat, their urine, their droppings and bite wounds. Besides direct contact it can also infect a human by breathing in dust particles that is contaminated with rodent droppings or urine. Once a human is infected they can spread this disease to other humans. Death is rare and recovery can occur within a few weeks to a few months.

Leptospirosis is a bacterial disease rats can carry and transmit to humans. This bacterial disease is transmitted to humans when humans eat foods or drink fluids that is contaminated with urine from an infected rat. If Leptospirosis goes untreated kidney damage, liver failure, respiratory distress, meningitis and even death may occur.

Most people think the Plague is an illness found in the history books however it still very much exist today. The Plague started in Europe in the year 1347’ and by 1350’ it was responsible for killing 1/3 of the population. This diseases is still found in the southwestern United States. The Plague is a bacterial infection that is spread by fleas and direct contact with an infected rat. Without immediate medical treatment the Plague can cause death.

Rat-Bite Fever is another bacterial infectious disease humans can get from rats. Humans can contract this disease from a rat bite or by a scratch from an infected rat or by touching a dead rat that has this disease or simply by eating or drinking food or liquid that is contaminated by an infected rat. Rat-Bite Fever is found all around the world including the United States. If left untreated this disease can cause death.

Salmonellosis is a bacterial disease that is found all over the world. Humans can get Salmonellosis from rats by eating food or drinking fluid that has been contaminated by rat feces. Salmonella is a microscopic living bacterial germ that causes diarrheal illness in humans and pets. It’s passed from the feces of rats or other animals including humans to other people or animals. Some animals such as rats may be a carrier of this germ but not show any signs of the illness. Salmonella is also passed to humans by handling the carcass of an infected rat.

Tularemia is another disease humans can get from rats. Many rats and other rodents may die during outbreaks. Human infection occurs when a human has physical contact with an infected rat. Humans can also contract Tularemia by drinking fluids such as water or by inhalation. This disease can be deadly to humans however most survive with the proper medical attention.

Besides the many diseases rats carry themselves they will indirectly responsible for infecting humans with murine typhus, leptospirosis, and trichinosis. The fleas on the rats are the main culprit. Fleas on rats have been known to transmit these diseases to humans through bits or by their feces.

Do rats cause asthma and allergies?

Researchers at John Hopkins Medical Center have proven that rats are a major cause of asthma and allergies in children that live in inner cities.

What parasites do rats carry?

Rats are known to causes flea infestations in homes, office buildings and warehouses. Many homeowners were unaware they had a rat problem until they started getting bit by fleas. Rat fleas can jump up to 200 times the length of their own body. Rat fleas are known to carry several different diseases that can infect humans. Some of these diseases are deadly and have been the cause of millions of deaths around the world. Rat fleas lay extremely tiny white eggs in the rats fur however many eggs fall out of the fur onto the floor, carpet, pet bedding, or in cardboard boxes. The tiny legless worm like larvae that hatches from the eggs does not yet feed on blood but feeds on the adult flea’s feces, dead skin cells and animal hair. After the flea larvae grows into an adult flea they are able to feed on blood. Adult rat fleas can live up to 1 year and one female can lay thousands of eggs in her short life.

Rats also carry ticks into homes and warehouses. The ticks that prey on rats also pray on humans and pets. These ticks are responsible for giving humans and pets Lyme disease. Researchers have performed studies in urban parks that prove the increased presents of rats increases the chances of patrons becoming infected by Lyme disease from rats.

How long do rats live?

In captivity rats can live an average of 2 to 2.5 years but in the wild rats only live an average of 1 year. Many different species of wildlife preys upon rats including humans, owls, hawks, large snakes, fox, raccoons, cats, more.

What do rats eat?

Norway Rats drink 1 to 2 ounces of water and some of their fluid consumption comes from moist foods. They eat .5 to 1 ounce of food per day to sustain a healthy life. This rodent is a scavenger and will feed on just about anything eatable they come across. Foods such as seeds, fruits, grains, animal matter, nuts, and insects are preferred. Rats on the lower level of the social hierarchy will by the first to die during times when food supplies are low. Rats may also convert to cannibalism when food is none existent.

Roof Rats are omnivorous and will eat just about anything if food sources are low. However, they tend to eat more like a squirrel then like a Norway Rats. Fruits and nuts are their preferred favorites but they also commonly feed on ornamental plants, livestock feed, dog and cat food, garden vegetables, bird seed, insects, small lizards, candle wax, paper, tree bark and more. Roof Rats are known to stash foods like nuts and seeds in or near their nesting site. Water sources are usually air conditioning condensation drip lines, water bowls for pets, leaking pipes, bird baths, and occasionally they will chew through pipes to access the water inside.

What does rat droppings look like?

Droppings from a Norway Rat and Roof Rat looks like a miniature cigar. Norway Rats leave behind ¾ of an inch long droppings with blunt ends and Roof Rats leave behind ½ long droppings but their droppings look the same. Fresh droppings are dark drown to blackish and shiny. If you pinch fresh droppings between your fingers it will flatten like a pan cake however if the droppings are old they will crumble and fall apart when pinched. Old droppings are also dull and may appear brownish to a dark tannish color.

What is the best animal control or rat control solution and how do I get rid of rats that are living in my home?

Pest and wildlife like rats have been surviving in close proximity to humans for thousands of years. In fact, certain species such as the Norway rat have to live in human communities and agriculture farms to survive. They have become so reliant on humans for food that they would perish if humans disappeared. Even though they have to live in close proximity to humans to survive they are very well aware that humans are a predator. Over time these rats have learned to avoid humans and the traps and poisons humans put out to control their populations. Rats are also a creature of habit and will take the same path over and over day after day. Once they feel secure with a path or trail they stick with it but if that path or trail is changed in any way they will instinctively avoid any new object on that path. This is why most homeowners fail when they attempt to resolve a rat problem on their own.

The most effective long term solution to your animal control needs is to contact a reputable licensed and insured professional. Mid-Atlantic Wildlife Control is the leading expert in Maryland and Southern Pennsylvania for rat control. They will use the most up-to-date effective methods to quickly take care of your rat infestation problems. Once the rat infestation has been controlled they will use rat proof materials to seal and repair all entry points. If you have any questions about rat control or if you are in need of any solution for animal control just give Mid-Atlantic Wildlife Control a call and talk with an expert.