Discovering Wild Rats: Everything You Need to Know

by Joshua Paulson

Discovering Wild Rats Everything You Need to Know


The rat is among the most common pests in the world. This long-tailed rodent is prevalent everywhere, apart from Antarctica and the Arctic Circle. They breed fast, which leads to quick infestations within buildings. The rodents hitch rides on planes and ships, which is why they are so widely spread.

However, rats play an important role in the ecosystem. Wild rats spread seeds, which promote tree growth. This leads to a sustainable environment. In the wild, rats are a food source for animals like cats, birds of prey, snakes, and weasels.

Here are some of the most important things you should know about wild rats and how to keep your home safe from infestations.

Brief History and Evolution of Wild Rats

There have been rodent-like mammals roaming the world for 66 million years. They appeared a short time after dinosaurs became extinct. Today, there are over 60 species of rats within the Rattus genus subdivided into seven different groups.

Wild rats fall under the Muridae family in the Rodentia order. The family includes mice as well. Mice and rats are believed to have diverged some 40 million years ago. The main origin of the wild rat is believed to be Southeast Asia. About 200,000 years ago, rats started spreading toward Southeast Asia and the Middle East. They then spread to Africa around trading and transportation routes where the population growth became even more rampant.

In North America and Asia, rat genus fossils appear in records dating back 54 million years at the beginning of the Eocene period. These rodents are believed to have evolved from anagalids, which are rodent-like mammals and the direct descendants of rabbits and hares or Lagamorpha.

Rats have thrived among humans for centuries. They are incredibly adaptable and can survive in the most unsanitary conditions. In human homes, they chew and gnaw mainly to trim their teeth. As such, wild rats damage property, spread diseases, and are known to spoil food supplies. These pests have become a natural part of the ecosystem. In some cities, rats outnumber humans. This is especially true in densely populated areas.

Even with the negative reputation, rats are valuable in laboratory settings. They are used widely in toxicology, physiology, and neuroscience. Lab rats make up 13.9% of animals that have been used for research purposes in Europe. They were first domesticated from wild rats more than 170 years ago. Their popularity as model organisms is due to their availability, short reproductive cycle, low breeding costs, and their capacity to survive in captivity.

Species and Varieties

There are two primary species of wild rat in the world today. These are Rattus norvegicus (Norway rat) and Rattus rattus (black rat).

Rattus Rattus (Black Rat)

They are also called roof rats. This rat is about five to seven inches long with a tail around six to eight inches in length. It can grow to a weight of between 75g-230g. This normally depends on the subspecies. The black rat has a slender body, large ears, and a pointed nose.

The black rat is agile and a good climber. This is why they are often called roof rats. They prefer consuming moist fruits and can eat about 15g of food in a day and 15 ml of water.

Even though they are called black rats, their fur can vary in color such as grey and brown. These rats don’t have preferences when it comes to food and will consume anything.

Rattus Norvegicus (Norway or Brown Rat)

These species prefer burrowing and ground living. The Norway rat grows to a length of eight to 10 inches, and their tails to around seven to 10 inches in length. This rat is one of the largest and can achieve a weight of between 250g-350g. However, it’s important to note that the rats can weigh up to 1,000 grams in some cases. This is mainly true with house rats. With a blunt nose and small ears, its body is much thicker compared to Rattus rattus.

Brown rats have brown or grey fur with lighter shades on the underside.

Rattus norvegicus prefers cereals for food even though they are omnivorous. Their food intake is 30g a day and can take up to 60 ml of water. These rats have poor eyesight but a good sense of smell and are incredible climbers.

Behavior and Habits

The primary rat species in the U.S. are the Norway rat and the black rat. Wild rats are terrestrial or arboreal within various habitats.

Most rats are nocturnal as opposed to crepuscular or diurnal. Some rat species are solitary while others thrive in small or large groups. Norway rats, for example, live in large packs while the roof rats live in much smaller groups. Most of the remaining species live either in small family groups or in solitude.

When in a large group, a hierarchy develops with the stronger rats becoming dominant. Female burrows are no longer protected and several males can mate with a female sequentially, following social dominance.

Rats become aggressive if they feel threatened and can box, bite, chase, and fight. Wild rat behaviors include belly-up and sidling defensive postures.

Wild rat in a corner of a house

Communication Among Wild Rats

Rats are mostly social animals. As such, they communicate with one another through pheromones or ultrasonic vocalizations. In the past, pheromone research concentrated on sexual behavior. However, some pheromones are used to signal danger. In a cage, rats can communicate information about a specific fear to another rat.

Rats have good hearing and produce ultrasonic vocalizations to communicate. These are meaningful ultrasound frequencies that humans can’t hear. Humans assume that rats are quiet, save for the occasional audible squeak. Vocalizing in high frequencies mostly happens when the rat is frightened or stressed and wants to express pain or discomfort.

Wild rats communicate physically through body language. Physical play can result in a fight, especially when dominancy is an issue. This natural behavior helps create hierarchies.

Grinding teeth is a rat’s way of expressing relaxation and contentment, and eye bogging to express happiness in rats.

Marking territory with urine allows rats to communicate with others in their surroundings. Through urine, other rats can identify the reproductive status, social hierarchy, gender, and age.

Diet and Feeding

Rats are omnivorous and have opportunistic feeding habits. Their teeth grow constantly which drives them to chew on rough and hard objects to control the growth. Rats consume almost anything they can access.

The main items in their diet depend on their habitat. In the wild, rats eat seeds, plants, and fruits. They can also consume insects and other smaller animals. In city settings, rats consume meat and garbage. They also eat human food and pet food if they come across any. This is why part of rat control involves securing trash bins and food sources.

Reproduction and Lifecycle

Different species have similar life cycles. Rats normally reproduce an average of seven offspring in one liter. However, the number can be as high as 14. A rat’s gestation period is three weeks, which means a single female can reproduce about four to six times in a year.

Rats take three weeks to mature. Sexual maturity is achieved at five weeks and they can start mating and reproducing. In terms of life span, Rats live for two to three years. To answer the question, “How long do rats live in the wild,” most rats die within the first year because of interspecies conflicts and predation.

Habitats and Distribution

Rats thrive in a wide range of habitats in wild forests and urban areas. There are meadow, field, wood, and forest rats.

Urban Settings

In urban settings, they tend to infest areas with shelter, water, and food. They can be found in homes, commercial establishments, dumpsites, drains, tube tunnels, and sewers. They build nests and reproduce in such areas.

Rats pose a great problem in society through property damage and spreading diseases. Due to the ample food and favorable habitat, rats can survive in such settings.

Natural Habitats

The natural habitat of wild rats ranges from forests to grasslands. Rats are adaptive to change and can thrive in a wide range of ecosystems. This is why they are found in large numbers in most parts of the world.

Wild rat on a rock

Pet Rats vs. Wild Rats

Almost all domesticated rats descend from Norwegian rats. While pet rats and wild rats look almost the same, some differences distinguish them. They also tend to behave differently when around humans.

Social Behavior

Rats in the wild aren’t social. They run when they encounter humans and only come close if there is food available. They also tend to congregate with others for mating. If they’re trapped, they become hostile.

On the other hand, pet rats are friendly towards humans. They are social with other rats (domesticated). However, they can bite when they feel threatened.


Normally, a rat can grow up to eight inches depending on the species. However, in wild settings, rats barely get to their full growing potential. Wild rats are smaller than pet rats because they don’t interact constantly with humans for feeding.

Pet rats are heavier than wild rats. This is mainly because they lack exercise within controlled environments. The rat’s life span is longer since they aren’t exposed to predators.

Myths and Misconceptions About Wild Rats

Most people shudder at the thought of finding rats in their homes. They are the least-liked pests because of myths and misconceptions about them.

Rats No Longer Spread Diseases

In the Middle Ages, it was claimed that rats carried deadly diseases due to uncleanliness. There is also a claim that modern rats are germ-free. While society has taken sanitation and health measures to prevent disease outbreaks, rats can still spread diseases.

It’s Quite Safe to Touch a Rat

More people are keeping pet rats which makes some assume that it’s safe to touch and play with them. This isn’t true. Even domesticated, rats can still bite if they feel threatened. Wild rats also scratch, bite, and attack as well. As such, they’re more likely to cause infection and sickness.

Rats Prefer Run-Down, and Dirty Places

When people think about infestations, they visualize a poor and unkempt environment. However, rats can thrive even in the cleanest surroundings as long as they have water, food, and a safe nesting place.

A New Perspective on Coexistence

To solve the whole human and rat conflict, we should alter our perspective. Dwelling areas shouldn’t be viewed as places totally under human control and constantly being invaded by rodents. Rather, settlements should be viewed as an ecosystem where rats live and thrive as well.

That’s not to say that everyone should love rats or that we should allow them to do whatever they like. It’s about focusing on how to manage the ecosystem that rats and humans inhabit.

Humans manage the ecosystem largely which means strategic planning and leadership are critical. Understanding the urban ecosystem means a long-term investment. We need to understand rat populations and what makes them thrive. The interaction between humans and rats needs to be understood.

We should change the urban landscape by embracing better garbage disposal. This will make it harder for rats to access food. Rat-proofing homes and keeping the surroundings clear will most likely discourage rats from entering homes.

Dive Deeper Into the World of Rats

There’s a lot to learn when it comes to wild rats. There is also a great risk associated with interacting with them as they can spread diseases and cause damage to our homes. However, we can’t overlook the important role that rats play in the ecosystem.

To ensure coexistence between wild rats and humans, rat-proofing homes to avoid infestation is important. It is also vital to embrace humane removal methods to relocate the rats to a place where they can thrive without harming humans.

For pet rat owners, Quality Cage products and services can help you take better care of your furry friend. You can source many rat supplies from Quality Cage. Getting a high-quality rat cage allows you to monitor and control rats better.


How do you keep wild rats away?

You can keep wild rats away by sealing gaps in walls, making sure food is stored in thick containers, keeping garbage cans closed, keeping the yard clean, and setting up safe traps. Consider adopting rat predators as well though this is a short-term solution.

What is the difference between a wild rat and a house rat?

House rats tend to be smaller than wild rats. They are also more sociable in comparison

Is it okay to pet a wild rat?

Domesticated rats are usually intelligent, sociable, and friendly. However, wild rats are wary of humans. They are more likely to bite when they feel threatened or afraid. Therefore, petting a wild rat isn’t safe. It’s best to leave them alone, as you would any other type of wild animal.


Have Questions About Wild Rats?

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Author: Joshua Paulson and Quality Cage Team
Josh is the owner and CEO at Quality Cage Crafters since 2015. During his time at Quality Cage Crafters he has been able to learn from tens of thousands of pet owners and pet educators. He blends his ambition for manufacturing and passion for animal care to create solutions for pet owners, breeders, animal rescues, and zoos. He has brought together a team of great animal lovers to create high quality pet care content for the Quality Cage Crafters audience.

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