The Complete Guide to Rodent Prevention, Treatment and Control in Singapore

Rodents are mammals with a high degree of intelligence. Rodents belong to the family Rodentia which houses many other animals such as squirrels, hamsters, and guinea pigs. Among all rodents, rats and mice cause the most problem to our living environment. They can infest food, damage houses and buildings, and threaten public health. A rodent infestation is said to be a real headache in the pest management industry. The skills of rodents make the controlling efforts a challenging task.

Table Of Contents

• What’s the Difference Between a Rat vs a Mouse?
• Types of Rodents in Singapore
• Life Cycle and Biology
• Medical Importance
• Signs of a Rodent Infestation
• How to Prevent Rodents from Invading Your Home
• DIY Methods to Get Rid of Rodents
• Professional Rodent Treatment

Though rats and mice have similar food preferences and may look similar, they are not the same. One of the key differences between a rat and a mouse is their size: rats are usually larger than mice and can grow up to 26 cm in length, while mice are typically around 5 to 10 cm. Their tails also differ, as rats have thicker tails compared to the slenderer tails of mice. Furthermore, rats and mice have different behavior and habitat preferences, as rats are generally more cautious, while mice are known for their adaptability and making nests close to people.

To tackle rodent infestations, individuals use various methods like rat and mouse baits, traps, repellents, and poisons designed specifically for rats or mice. It is important to identify whether you have a rat or a mouse in your house to choose the right pest control methods.

There are 3 common rats and mice in Singapore, which are Norway rats (Rattus norvegicus), roof rats (Rattus rattus) and house mice (Mus musculus).

Norway rats are the biggest (body length range from 22 to 26 cm) among the three common species. They are also known as sewer rats, as we can always find them in the drainage system. Thus, that is one of their main travel pathways. Norway rats can be distinguished by their size, heads, ears, and tails. They have a robust body appearance, with a blunt muzzle and a shorter tail than the body.

Roof rats are famous for their climbing abilities. They are so-called agile climbers and are primarily found in elevated spaces. They have a smaller size (about 16 to 20 cm of body length), a head with a pointed nose, larger eyes, and ears similar to that of Norway rats.

The size of a house mouse is about 5 to 8 cm. Thus, they are smaller in size compared to rats. Like roof rats, mice also possess large ears and small black eyes.

Rodents are excellent in hearing, tasting, smelling and touching. However, they have poor eyesight. They are nocturnal animals, meaning that they are primarily active at night. As mentioned, rodents are smart. They explore and constantly learn, memorize food, water, pathways, nests, and the features of their environment. In addition, they have neophobia behaviour. Rodents usually avoid new objects such as traps and baits for a few days or more following their initial placement.

Norway rats are usually found at building foundations or lower levels of the buildings, especially in the basement. They are the main burrow builders and excellent swimmers. Norway rats can reach sexual maturity in about 2 to 3 months. They can reproduce and breed throughout the year in favourable conditions. One female can give birth to about 5 to 14 litters per year.

Roof rats are agile climbers who usually nest at a higher elevation, such as false ceilings, attics, cabinets, trees and dense vegetation. When roof rats invade buildings, nesting materials such as shredded paper, newspapers, and dried plant materials are used. You can always see them running along utility pipelines and overhead fence tops. One female roof rat can produce 3 to 5 litters per year.

House mice are also excellent climbers. They can even squeeze through holes of less than 1 cm in diameter because of their tiny size. House mice can have 5 to 10 litters in a single year. They can also easily enter buildings. As a result, house mice infestations are more common and severe than rat infestations.

Rats and mice are capable of causing structural damage and transmitting diseases (to human beings) such as:

• Rat-bite fever
• Salmonellosis (food poisoning)
• Leptospirosis

Diseases are transmitted through bite wounds, food, waste products, or indirectly by fleas, ticks and mites via close contact.

Here are some of the symptoms of rodent-borne diseases: 

• Fever 
• Chills 
• Muscle aches 
• Headaches 
• Cough
• Nausea
• Vomiting
• Loss of appetite

In severe cases, some symptoms may show, such as: 

• Weight loss 
• Fatigue 
• Swollen ankles, feet, or hands 
• Decreased urination 
• Shortness of breath
• Rapid heartbeat
• Jaundice
• Confused mental state
• Aggressive behaviour
• Seizures
• Inability to control your movements
• Inability to speak
• Aversion to lights

Rodents are nocturnal animals. We often do not notice their presence until the infestation becomes severe. Here, we will share the tell-tale signs of a rodent infestation.

1. Gnaw marks

As mentioned, the incisors of rodents never stop growing. This is one of their survival behaviours! They gnaw their incisors to gain food, and resources, invade buildings, build nests, assist in climbing and use them as weapons to fight the enemy. Rodents are seemingly attracted most to electrical wires and wooden structures.

2. Bite signs on food packaging

Rodents can bite through many food packages such as plastics, paper sacks and cardboard. Their teeth are strong and sharp enough to bite through those materials to obtain food.

3. Rodent droppings

Rodents can produce 20 and 30 droppings in a single day. In short, droppings are a good indicator to inspect for rodent activities. Furthermore, the shape and size of droppings can help in checking for rodent species.

4. Rub marks

Rub marks refer to the dark grease left by rodents when they follow a trail or pathway between their nest and available food source. The dark grease or dirt marks are caused by the oily fur of rodents.

5. Urine stain and odour

In heavily infested rodent areas, we can sense stale smells coming from hidden places. Rodents use scent to mark their territory, and convey information and social dominance.

6. Burrows

Norway rats’ burrows are always found along with building foundations, especially in the external garden area. When they invade the building, they usually nest at lower elevations.

7. Live/dead rodents

Seeing a live or dead rat or mouse on your premises is a potential sign that you have a rodent infestation. Also, if you find rodents during the daytime, this may indicate that you have a heavy infestation on your premises.

You may have probably been disturbed and heard rodents squeaking at night or see them running in the kitchen area or backyard. This is because they always live near humans, searching for food that people leave behind.

As mentioned, rodents are excellent swimmers or agile climbers. For them, it is not a difficult task to find a way to invade our premises. Hence, how do we prevent them from coming in?

1. Make sure rubbish bins are always covered properly

Rodents, especially house mice, can squeeze through tiny spaces. It is advisable to always keep rubbish bins closed. As such, they are denied access and cannot gain food from bins.

2. Empty your bins before night falls

The smell of food waste in kitchen bins can attract rodents and other pests to thrive. Rodents are nocturnal pests. So, make sure food waste is always disposed of daily before night.

3. Seal up potential entry points

Both rats and house mice are capable of climbing. Therefore, make sure to inspect buildings, especially rooflines. Also, be aware of the potential rodent entry points and take necessary sealing and repairing works on the entry points found.

4. Trim bushes and trees

Rodents use thick foliage to protect and cover themselves from predators. Roof rats and house mice can climb up to buildings or premises from shrubs and trees near the exterior foundation. Hence, always make sure to trim bushes and trees around your premises to prevent giving them a favourable environment to thrive.

5. Store food in the right way

As rodents can bite through food packages, storing food in tightly sealed containers or placing food in the refrigerator is essential. The same goes for pet food, which should not be left out all day long or overnight as it will attract rodents and other pests.

6. Reduce water sources

Leaking pipes need to be fixed to reduce available water sources for rodents and other pests. The drainage system also needs to be improved if standing water is sighted and the drains are blocked. Besides, floor traps need to be covered at all times to prevent rodents from coming in through the drainage system.

Set your own rat/mousetrap:

1. Buy traps in the market (it is recommended to buy traps that can prevent them from suffering).
2. Make your own traps by referring to online tutorials (avoid catching the live one as you may need to kill or starve them afterwards).
3. Choose peanut butter as the bait rather than cheese (they prefer high protein and oil-based food).
4. Place traps perpendicular to walls (as that is their pathway).
5. Wear removable gloves.
6. Dispose of them by using tightly sealed black plastic bags.

In the case of a severe rodent infestation, treatment methods can become complicated. It is usually the combination of at least 2 to 3 methods to identify and solve a heavy rodent infestation. Help from a professional pest control company is strongly advised.

Exclusion

Identifying rodent entry points can be challenging to untrained eyes as mice can squeeze through dime-sized holes. These tiny holes can be easy to miss out on. Our pest management technicians are trained to inspect and identify the potential holes rodents or mice might use to gain food in your premises.

Rodenticides

When the rodent infestation is severe, we might need to place rodent baits outside the premise to achieve adequate control. Rodenticides are placed in a tamper-proof rodent bait station to avoid non-target animals from feeding.

Trapping

Pre-baiting 

As rodents have a neophobia (bait shy) effect, pre-baiting is usually the initial stage to ensure they feed on the baits placed in the traps. The baits that we use are non-toxic and formulated with more than 15 human foods to gain attraction.

Trap with baits 

After pre-baiting (usually about a few days or weeks), traps with the same baits will be activated. This stage usually proceeds until no more rodents are trapped and signs of infestation are not sighted anymore. 

Our trap can send an alert to us once the rodent is caught. Then, immediate removal of the carcass can be done.

Rodents live in close association with humans and feed on whatever humans eat. Hence, you might have been providing them food without even knowing it! Therefore, maintaining the best housekeeping practice is the most reliable method to keep your premises clear from pest invasions.

However, controlling and catching rodents on your own is not a good idea when it comes to heavily infested areas. Instead, seek help from professionals now!