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How Many Babies Can A Rat Have?

Last Updated: 16.04.24


Although they can make cute pets, rats are still mainly seen as pests throughout the world. And, even though you don’t want to get rid of them right now with the help of some good traps for rats, you might still want to consider some mouse traps that work in the future since they are known as fast breeders.

Rats are fascinating creatures that are more similar to humans than we would like to admit. In fact, we share 99% of our shared genes with rats, and about 97.5% of our working DNA, according to scientific research. In other words, there is only 2.5% that turns us into men and women rather than rats.

The striking similarities between the two species don’t stop here. On the contrary, it is mainly the reason why rats have become so popular in medical researches and there were millions of tests and experiments conducted on them, in the attempt of curing certain diseases or understanding how our health system works.


Rats across the world

It wasn’t until the 19th century that rats were considered suitable as pets, after Queen Victoria’s personal rat catcher, Jack Black, found various color variations of the popular brown rat, and started domesticating the new breeds.

However, contrary to popular opinion, not all rats live close to human habitats. In fact, out of around 56 species of rats, only a few tend to live near buildings, farms, and human-inhabited places. Most of these rodents prefer living in rainforests and marshlands, away from civilization and human contact.

Out of the most common rat species that live close to humans, the brown rat is the most popular. Its presence is scattered around the globe as it can withstand harsh weather temperatures and conditions.

Rats are strong animals that can live without water for three days, and even survive being flushed down the toilet. They are omnivorous and, therefore, tend to eat everything, including leftovers, garbage, and other small animals.

They also have a strong immune system and can survive a fall from over 50 feet high without being injured.

Rats as pets

As we previously mentioned, people might consider certain species of rats as good pets. They are very smart and loyal, and even loving after they get acquainted with their owners. Unfortunately, due to their short lifespan, rats don’t always make suitable pets for small children.

They are also mainly nocturnal creatures, meaning they stay active during the night, which may interfere with your child’s sleeping schedule at some point. In addition, rats are very fast and can easily escape if you don’t hold them properly.

Although all rat pets are vaccinated, they might still be disease carriers, just like any other animals. Rats can cause allergies and, if they have been in contact with other wild animals, they may also spread rabies or other dangerous diseases. Therefore, make sure your rodent is vaccinated and keep it in a cage or only inside the house.


Breeding facts

Rats are fast breeders and, given the right survival conditions, they can rapidly explode in numbers and become dangerous to you, your house or crops. Depending on the species and the fertility, a single pair of rats can produce up to 3,500 offspring in three years.

Female rats reach maturity quite soon and are theoretically ready to give birth to babies after just six weeks from birth. However, the number of cubs she delivers and the frequency depend on the species of rats we are talking about.

The gestation period for all rats is around 21-24 days, and rats can theoretically mate up to 17 times a year. However, these rodents have a different breeding strategy than people do.

Just like most other animals, rats breed solely for the survival of the species, meaning they are genetically programmed to give birth to as many cubs as possible. In their world, quantity is more important than quality, and this is why not all baby rats survive.

Natality differs depending on the environment and natural resources. If rats live in a welcoming environment with regular temperatures and enough food, the cubs have a better chance of surviving. If the food is scarce, only the strongest pups will survive each time.

However, most rats usually mate 5-7 times a year. When it comes to the most common rat species, the brown one, it is known that each female gives birth to 5-10 babies a time. The number of babies slightly differs depending on the rat breed, so that the common ones used as pets are able to bring 7-9 babies into the world at once.

In other words, rats are very prolific creatures and enjoy living in big colonies. If left uncontrolled, they can become real problems, especially since they are disease carriers.

As pets, rats should be kept separated by sexes. They prefer living in pairs but they should have different cages unless you want to be picking up baby names for the next couple of years. Moreover, babies should be separated from their fathers immediately after birth if you want them to survive.

What factors limit the litter size in rats?

As we previously mentioned, most rats will mate 5-7 times a year with an average of 6-12 babies per litter. However, there are certain factors that influence the number of babies a female rat delivers, as well as their frequency.

Apart from the obvious food supply concerns, female rats also tend to reproduce less once they are headed toward menopause, which usually happens around the age of 18 months. It goes without saying that abstinence is the best policy in this case as well, so, if you don’t want your pet to have babies, make sure to keep it separated from the opposite sex individuals.


How to tell if your rat is pregnant?

Unfortunately, there aren’t too many ways to determine whether or not your female rat pet is pregnant. She is good at hiding the signs of pregnancy and, just like in the case of other rodents, she won’t change her behavior until a couple of days before giving birth.

During that time, females can be seen nesting and can become more aggressive. Therefore, we don’t suggest holding them or getting too close to them because they get territorial and might bite you.

Only a veterinarian can tell for sure if your pet is expecting or not so if you don’t afford to pay for a visit a few times a year, all you can do is wait.

On the bright side, female rats make excellent mothers and they usually provide everything necessary for the babies to grow up strong and healthy. However, we do suggest consulting with a vet and see if the new mother requires some supplements or vitamins to be able to look after all her cubs.

Sometimes, not all newborns will be able to eat as much as required, so you need to keep an eye on all your new pets.




1) Species and description of the rat

2) What would you call a baby rat?

3) Rat Reproduction Cycle

4) How many babies do rats have per litter?



Leave a comment


Ruth Malong

November 21, 2019 at 8:12 pm

I found what appears to be a nest of baby rats in one of my palm trees. When checking with a rake 3 babies fell out. I raked them up and tossed them in the yard rubbish can. Who should I call to get rid of the rest?


November 22, 2019 at 8:34 am

Hi Ruth. You should call a pest control company from your area. You can check out this company: I hope this helps.

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