A female rat can carry between 3 and 15 babies per litter every 3-4 weeks.
However, the number of babies depends on the type of rat. Norway rats can produce 12 babies because they can feed 12 babies at a time. On the other hand, roof rats can only care for ten babies, so they usually have smaller litters of 5-8 babies.
Considering female rats can get pregnant after giving birth if housed with male rats, a female rat typically births as little as 35 and as much as 200 babies annually.
Let’s learn more about different types of rats and their breeding habits.
How Many Babies Do Rats Have?
Female rats reach sexual maturity at 8-12 weeks, while males reach maturity at 6-10 weeks. After they reach sexual maturity, they should be housed separately.
Otherwise, they can breed every month. The average gestation period lasts between 21 and 23 days. You can’t tell a female rat’s pregnant immediately.
After about two weeks of pregnancy, most rats start showing signs like weight gain and breast development. You can also tell a rat’s pregnant by touching her belly.
Pregnant female rats will make a nest for their litter using tissue paper, shredded paper, paper strings, and other materials.
See How Long Is A Rat’s Pregnancy?
Different types of rats can carry different numbers of litter. For instance, some can have less than five, while others can deliver over 15 babies.
What Happens After Delivery?
Rats deliver blind and deaf babies. Their nest or cage should remain in a quiet spot, and no one should disturb the babies for at least a week after birth.
Typically, weaning happens 21 days after birth. The mother can become pregnant again after delivery, but it’s not good for rats to be pregnant and nursing simultaneously.
Females should rest for at least two months before getting pregnant again because rest helps restore their full strength.
What Affects the Breeding and Reproduction in Rats?
Breeding and reproduction in rats can reduce because of various factors, including age, abnormal light cycles, malnutrition, cysts on the ovaries, coldness, inappropriate nesting materials, and tumors.
Moreover, pregnant female rats can abort, eat, or abandon their babies for reasons like lack of water, improper food, improper nesting materials, overcrowding, deformities and sickness in the babies, or excessive noise.
However, healthy rats rarely have reproductive difficulties.
How Many Babies Do Wild Rats Have?
The type of rat determines how many baby rats a female rat will have.
Take roof rats and Norway rats, for example. You can find roof rats in the coastal areas, whereas Norway rats can live almost everywhere.
Female roof rats can deliver about 5-8 babies per litter, as they have ten nipples. On the flip side, Norway rats have 12 nipples and can carry up to 12 babies per litter.
When Norway rats become sexually mature, they can have about 6-15 babies per litter. However, they often carry as many babies as they can naturally nurture.
Norway and roof rats have similarities and differences in breeding and reproduction.
For instance, both species produce many babies, but roof rats have fewer offspring per litter.
How Many Babies Do Rats Have in a Lifetime?
The number of babies rats have in a lifetime depends on the type of rat and many other factors. However, the average litter size varies between 3 and 15.
Assuming the female rat will get pregnant every month, she can produce a maximum of about 200 annually.
Most types of rats have a lifespan of 1-2 years; they can produce up to 400 babies in a lifetime. However, some of those babies never reach maturity for many reasons, so we can never determine the exact number of babies.
How Many Babies Do Rats Have in a Year?
Female rats can deliver babies every 3-4 weeks because they get pregnant again after birth. Luckily, female rats seldom get pregnant this often.
Some types of female rats can carry between 13 and 17 pregnancies annually.
However, the average female Norway rat has about 4-6 litters, while the typical roof rat carries approximately 3-4 pregnancies yearly.
The number of babies born doesn’t equal the number of those who reach maturity. Roof and Norway rats become adults within three months after birth.
A female Norway fat can produce about 30-60 rats annually, but they usually wean only 20 rats yearly./h
How Many Babies Can a Rat Have in a Month?
If you house sexually mature male and female rats, the females can give birth every 3-4 weeks.
If you’re breeding pet rats in captivity, you should leave the female rats alone for at least two months. The rest will help female rats restore their health after delivery.
Most female rats have 3-15 babies per litter, but the number varies by species.
How Long Do Baby Rats Stay With Their Mother?
Most baby rats stay with their mother for around six weeks. This period includes nursing and weaning at five weeks or 21 days.
Final Words
Rats in captivity can reproduce all year round. However, wild rats can only breed during spring, summer, and fall.
Winter isn’t suitable for breeding in rats because of the cold conditions. Nonetheless, rat populations grow fast because they can carry 3-15 babies every 3-5 weeks.
The Unique Traits of Baby Rats
What’s interesting about baby rats is that they’re born deaf, blind, and hairless. Mothers care for their babies for approximately 21 days.
When baby rats reach four days, their ears develop. Within ten days of birth, they grow hair; after a week, baby rats finally open their eyes.
Within two months after birth, female rats become sexually mature and can start having babies.
Do Wild Rats Breed in Winter?
Wild rats usually don’t breed during winter because of the cold weather.
Moreover, indoor rats live longer than wild rats. Most wild rats have a lifespan of 1 year, but indoors, they can live up to 2 years.
When the temperatures and food sources drop, most outdoor rats, including white, black, and brown rats, make shelters in people’s homes.
If they make a shelter in your home during winter, they have higher chances of breeding and increasing their population. Therefore, if you have a white, black, or brown rat living in your home, act immediately and call your local rat control experts.
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