Rat Breeding: Comprehensive Expert Tips & Tricks

by Joshua Paulson
Rat Breeding: Comprehensive Expert Tips & Tricks


One of the most adorable (and sometimes worrying) things that can happen to any pet owner is their pet having offspring. Seeing those tiny creatures does spark a special joy.

However, it’s essential to do it in a controlled environment. Make sure that your pet is ready for breeding. It should also be noted that pet rat breeding is not something that you should embark upon lightly, as taking care of breeding rats is much more demanding than having one or two.

Although it takes up to six months for a rat to fully grow, it will be ready to mate in about five to eight weeks. Additionally, a rat’s short estrus, gestation, and growth cycles mean that a female can have six litters per year, each with about 10 young. That’s about 60 new rats per year from a single breeding female.

We’ll discuss everything you need to know about breeding pet rats.

Understanding Rats: An Overview

Rats are social creatures whose survival mainly depends on hiding and producing enough offspring to adulthood. If left unattended, rats will multiply rapidly. Unlike hamsters, female rats aren’t aggressive towards male rats, even if they aren’t ready at the moment to mate. Their estrus cycles are only days long, so a female rat might take only a week to become pregnant.

Having this in mind, it’s best to keep your male and female rats separate. Quality Cage has a wide variety of rat cages to choose from.

Rat Breeds and Their Traits

There are several types of rats, and each has its characteristics. However, all domestic rats are a domesticated form of the common brown or Norwegian rat, classified as Rattus norvegicus domestica.

Fancy rats are the most common ones you will find at pet stores. These rats have slim bodies and short fur. They can be found in over 40 colors of fur and up to 11 recognized patterns. If you are dealing with these, you might make the decision to breed them rather easily, as they are the most widespread and looked-for type of rat.

Hairless rats look just as the name suggests. They were mostly associated with laboratory research but can be found as pets now. Their skin is highly sensitive and requires special care. This might make breeding and having healthy offspring a bit more difficult. Plus, not everyone will be attracted to these, and therefore you might find it more difficult to sell or give away the pups.

Rex rats are known for their curly fur. The mutation that causes their fur to be curled can do the same to their whiskers. They’re one of the most popular breeds among rat lovers. However, they have a destructive nature and shouldn’t be left alone for a long time. Breeding a rex with a no-rex will not guarantee the pups to have curly fur. So, in case you want to breed your fancy rat with a rex rat, it might not even be worth the hassle of trying to find one, as there’s no guarantee the pups will inherit the Re gene.

A dumbo rat is characterized by its very large, round ears. However, for a non-trained eye, they might seem like ordinary fancy rats.

A rat’s breed shouldn’t play a crucial part in deciding if you should breed your rats or not. Keep on reading to find out more about other factors that can influence your decision.

Rat Behavior and Social Structure

Rats are social creatures and have a hierarchy in their community. Like with many other animals, there’s an alpha male. If left to choose a male themselves, female rats would naturally go after the alpha leader, in hopes to have their pups with them.

Two curly haired rats

Preparing for Rat Breeding

The first thing you need to do is to decide what is the purpose of breeding your rats. If you wish to sell them, ensure you have enough space to keep the babies (which are called either kittens or pups) before they’re sold. After this comes the choice of which rats you want to breed.

Selecting Breeding Rats

Make sure that the female rat is grown enough to have babies. If a smaller rat gets pregnant unexpectedly, you can take her to a vet for a check-up. It’s usually much safer for the rat to have the babies than to terminate the pregnancy. She might not be able to feed all her babies.

First-time mothers might not know how to care for offspring, and their instincts might need a few litters to kick in fully. Females that are too old might struggle due to old age and underlying health conditions.

Make sure that the rats that are mating are in good health. This will impact the offspring’s health as well. Especially look out for respiratory problems, as susceptibility to those is one of the most common health issues in rats.

Another thing to consider is the temper of your rats. Choose well-behaved ones, as you want to get offspring with the same qualities.

Health Check and Veterinary Assistance

Before you decide to breed a particular rat, you should take them for a check-up. In order to get healthy babies, it’s crucial that the parents are healthy too. Also, try not to breed rats that are related.

Preparing the Breeding Environment

A single female with a litter needs about 125 sq. in. of space, so make sure that your breeding rat cage has enough room. The bigger cages are better. If the cage has a wheel, make sure it is at least one inch off the floor. Otherwise, a young rat may crawl under it, get stuck, and suffocate.

Once you’ve selected a breeding pair, put the doe and a buck together in the same rat cage. Leave the male there for at least 10 days. If you keep male rats together in a cage, remember that other males might have difficulty accepting him later. This is because they will feel the female’s scent on him.

Feeding and Nutrition for Breeding Rats

A healthy diet should always be imperative when talking about rat care. In case you wish to involve them in breeding, double-check your rats have all the nutrients they need in their rat food. Provide them with fresh fruits and vegetables more often.

The Breeding Process: From Mating to Birth

The breeding process has stages with distinct features regardless of the type of rat:

Stage Time Frame Expected Behaviors & Changes Care Tips
Mating Day 0 Mating behaviors such as chasing, mounting, etc. Ensure a comfortable, stress-free environment
Early Pregnancy Day 1-7 Few noticeable changes, slightly increased appetite Continue providing a balanced diet, minimal handling
Middle Pregnancy Day 8-14 Weight gain, enlargement of abdomen, nesting behavior starts Increase food portions, provide nesting materials
Late Pregnancy Day 15-21 Significant weight gain, increased nesting Monitor closely, limit handling, prepare for birth
Birth Day 21-23 Delivery of babies, mother cleans and nurses newborns Do not disturb, keep the environment quiet and warm
Post-Birth Day 24 onwards Mother cares for babies, babies begin to grow fur Monitor health of mother and babies, prepare for weaning

Mating Behaviors and Timing

Although a female won’t be aggressive towards her mate even if she’s not ready for mating, there are two telling signs that she is receptive to mating:

  • She’s wiggling her ears often and fast.
  • She’s arching her back to make her vulva exposed (lordosis behavior).

Once you have determined she’s prepared, leave her overnight with a male rat in a separate cage.

Pregnancy and Birth

A rat’s pregnancy lasts 21 days. It’s best to let the doe deliver the pups on her own. Don’t touch her stomach while pregnant, as it may cause a female rat to lose her babies. Prior to giving birth, you can take her to a vet for a quick check-up, to make sure no complications happen.

Remove the male from the cage before the female gives birth. Otherwise, the female might become pregnant shortly after giving birth. This can overcrowd the cage and cause the older litter to get weaned off earlier than usual.

The rat gestation period lasts roughly the same with their nursing period, so a female can theoretically have back-to-back litters (i.e., nurse while pregnant). However, this is not encouraged for pet breeding, especially for novices.

Caring for the Mother

Female rats are considered to be good mothers. They take care of their babies and might even adopt orphans or “kidnap” other babies to nurture.

A mother rat doesn’t need a special diet. She just eats more, so leave her plenty of food and water. It’s also good to separate her from other rats, as she will need additional space. Don’t mess with her cage too much in the first few days, as she might feel threatened and start looking for a place to hide her babies.

After having her babies, it’s best to let a female rat rest for two months before getting her pregnant again. You’d want her to regain her strength. Also, she will take care of her babies for three to four weeks.

Caring for the Newborns

There isn’t anything you should do when it comes to newborn rats. In the first 21 days of their lives, their mother will take care of them. All the babies need is their mother’s milk. For the first 14 days, the babies are blind. When they’re born, they won’t have any fur, but it will grow in a couple of days.

After the three weeks pass, you can start thinking about separating them from their mother. After they’re weaned off milk, they eat most of the same food that the adult rats do. Rats reach sexual maturity relatively early, so you’ll need to separate the litter by gender after five weeks at most to avoid crossbreeding.

Mice on human hand

Common Challenges and Solutions in Rat Breeding

One of the first challenges you might face is the choice of which rats to breed. Choosing healthy and good-tempered rats will give you pups of the same qualities.

Health Issues

When choosing rats that you wish to breed, take into consideration their health. Choosing the strongest and healthiest from the group will give you the best quality pups.

Also, if you’re breeding your rat with someone else’s rat pet, make sure they’re healthy too. You don’t wish your rat to get a disease from another rat.

Behavioral Issues

Just like with people, behavioral changes in rats can be signs that they’re facing health issues. Some of these signs include staring, head tilt, hunched posture, sneezing, failure to groom, and stumbling. In case you notice any of these, pay a visit to the vet. You don’t want to breed a rat with potential health problems, as this will affect the pups negatively.

Ethical Considerations in Rat Breeding

If you decide to breed rats, you can’t do it unsupervised. You could easily end up with numerous rats, as they breed very often and can have up to ten pups each time. You probably wouldn’t have the space for all of them, and letting them in the streets would be a certain death for them.

Also, don’t pressure your rat in having her next pregnancy sooner than two months after the previous one. She needs her rest and time to take care of her pups.

Breeding for Specific Traits

You might wish to breed certain rats in hopes of having pups inherit their traits. But keep in mind that, just like with people, there’s no guarantee that they will inherit these. For example, pairing your rat with a rex rat doesn’t guarantee that you’ll get curly pups.

Managing a Rat Breeding Business

In case you decide to deal with rat breeding as a business, there are certain things to keep in mind.

First of all, you’ll need to take your rats for check-ups to make sure they’re healthy and will produce offspring of good quality. You should also choose good-tempered ones, as you want their babies to be good pets too.

Similar to keeping rats as pets, start out with two rats, one male and one female. When you get viable breeding offspring (i.e., a rat with the characteristics you want to breed further), you can pair a female with their father with no notable issues.

Down the line, you’ll need more than one female, as it’s too stressful for a female not to have a two-month break between pregnancies. Another thing that will be required is a lot of cages and space. Babies stay with their mothers for three weeks, and rats can have from five to a dozen young. Even after these three weeks expire, no one’s guaranteeing you that you’ll have a buyer for all the babies. Excessive rat supplies will also be needed with this number of rats.

While a female rat can ideally produce six litters per year, a novice breeder is more likely to get two good litters from a single female in her lifetime (24 to 30 months).

Reptile stores and pet owners can usually buy rats for food, but you might need to build up your connections over time.

Always make sure that your rats are fed and healthy. Using them only for breeding can be tiring for them.

When it comes to the promotional part of the business, try to spread the word as much as you can. Be active on all social media as much as you can. Try to post informative content as well. You want future customers to trust you, not just see you as a salesperson. Convince them that your rats are being treated ethically. Tell your friends to mention you whenever they can. Once you do close a sale, stay in touch with your buyer and offer advice when needed.

You can also search for local communities of rat breeders. They can provide invaluable information on which rat breeds are in demand and how to safely care for your rats.

Resources for Further Learning

In case you wish to find out more about rat breeding, here’re a few sources that could help you:

These are primarily for laboratory rats, but some principles can transfer over.

Key Takeaways: Creating a Thriving Rat Breeding Environment

Rat breeding is generally a very undemanding task. You just need to leave two rats alone and the job is done. Caring for a pregnant female rat isn’t hard either, as they don’t require much assistance. They will only need personal space and additional food and water.

However, there are certain things you should check on your list, in case you decide to let your rats breed. Make sure that they’re in good health and have a good temper to become future pets. These traits get passed on the offspring. In order to keep rats healthy and happy, be certain that you have enough space for everyone once the pups arrive.

Some of you might be considering rat breeding as a potential business. While it may seem like easy and fast money, keep in mind that you’re dealing with animals that still need love, affection, and fair treatment. You don’t want to exploit them. Give each female rat a two-month break after pregnancy. Your customers will also appreciate you more, if they see you as someone who truly cares for the well-being of the animals they’re keeping. Be sure to promote your business on all social media and keep the content entertaining.

In case you decide to go down this road, check out Quality Cage’s website and get all rat supplies on time before the babies arrive.


How long does it take rats to breed?

Leaving two rats in a cage for 10 days should get the work done. This is the length of two estrus cycles, ensuring that the female will be receptive at one point.

The pregnancy will last 21 days. A female rat can get pregnant again after just 48 hours after giving birth, with the next estrus cycle taking place after weaning the old litter. However, rats should ideally have no more than six litters per year to keep things simple.

Are rats easy to breed?

Yes, rats breed opportunistically and often. Having this in mind, take good care not to let them breed uncontrollably, as you might end up with 100 rats in a very short period of time.

How many babies does a rat have?

Rats can have from five to 12 babies at a time.

How do I get my rats to breed?

Rats don’t particularly care about who they mate with, so a pair of rats will almost certainly produce a litter given enough time. If a female paired with a healthy male doesn’t get pregnant or keep its young alive for two consecutive months, she might have fertility issues and is likely not breeding-worthy.


Have Questions About Rat Breeding?

Email us at cages@qualitycage.com

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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