Can Rats Get Pregnant Without a Male?

Can Rats Get Pregnant Without a Male
Can Rats Get Pregnant Without a Male

Rats make for great, very social pets. They’re good for kids, rarely bite and are very affectionate towards their owners. If you love your furry little rodent friend, you might’ve thought about it having babies, which could’ve gotten you wondering if the female rat can just have babies on her own. 

So, can rats get pregnant without a male? No, rats can’t get pregnant without a male. Unless you’re a professional geneticist working in a lab, extracting stem cells from female donors and inducing pregnancy artificially, there’s no way that your female rat is going to get pregnant without mating. 

In short, rats need a male to get pregnant. Once you’ve found a mate for your rat, you can expect a litter, but before you do that, let’s learn about the body of female rats, the mating process, and birth. This will help train you for what’s to come.


Sexual Maturity

Rats can be considered sexually mature once they are five weeks old. Separation of male and female rats should be done during the 3rd or 4th week. Rats can mate with their parents and siblings, so keep them separate regardless of pedigree.

There’s not a particular breeding season for rats; however, they refrain from mating during extreme weather. Females that are capable of breeding are excited every 4-5 days. They can come into heat during early pregnancy as well. The ovulation schedule is pretty regular and can be noted down, but it might vary some days. Sexual excitement in female rats begins during the evening and lasts until dawn.

A female rat’s cycle becomes more irregular as she ages. Menopause is observed when the rat turns 18 months old, and reeding during this time is dangerous for her health. As her fertility is waning, she’ll produce a smaller litter. Female rats can get pregnant after menopause, but there’s a high chance the pregnancy will be abnormal.

Breeding, for the first time, should be done when the female is 4-5 months old. Don’t risk breeding females older than 6-8 months for the first time since their birth canal is narrowly fused at the bottom. 

A Cesarean-section might become necessary as she’ll be unable to deliver normally. If you observe a difficult birth in a female at any age, avoid breeding her. Wait at least two months between the weaning period and a new pregnancy. Give the female rat time to recover and stabilize both mentally and physically.

As for male rats, age is not that important. Males are fertile even when they’re old. 


Mating will occur if you put a pair of fertile rats together for a night, given that they both are going through their heat cycles. If the female is aggressive, place the pair together when only the female is excited. 

It’s not too hard to recognize if a female rat is in a heat cycle. Her vagina is gaped open, and she shows behavioral signs. Upon stroking her back, she performs a sort of mating dance that attracts the male. If you don’t want her to get pregnant, keep her properly locked as she’ll try to escape the cage and visit a male. 

You must also keep the male and female rats separate regardless of either being in a heat cycle. Persistent males can stimulate females and excite them. During mating, males mount on the female rats several times, so don’t interrupt during the process.

Gestation Period

The average gestation period in rats is around 22 days, with the longest pregnancies stretching to 27 days. At around two weeks pregnant, the mammary glands start to enlarge, and the abdomen expands.

During the gestation period, give the mother a nutritious diet and a good amount of nesting material (tissue paper works fine!) to ensure a smooth delivery. Remove the father rat before birth. He will likely not hurt the pups, but he might get the female pregnant again (which is bad for her health).

If you have multiple rats in one cage, make sure there’s enough space to give the mother her privacy. Avoid leaving two pregnant rats in one cage. Avoid putting a new rat in a pregnant or nursing rat’s cage, unless the new rat is a baby the size of her own. This should be done only for fostering.


The process of giving birth in rats takes 1-2 hours. A new pup is delivered every 5-10 minutes. On average, the size of the litter is 6-13 pups.

A sign that the rat’s giving birth is the discharge of blood from the vagina. Contractions will start happening, and the mother will deliver with help from her hands and mouth. The umbilical cords and placentas are eaten by the mother. A mother may eat a dead baby.

Female rats are mostly wonderful mothers. They might be stressed due to pain during birth or some environmental factor. You can remove the baby and return it when the mother settles down. Keep the baby warm during this time and avoid separation from the mother for more than 3-4 hours. Examine the babies daily to identify any problems. 

Reproductive Problems

Reproductive issues are uncommon in healthy rats. They only arise in unhealthy rats or due to some factors including age, extreme cold, loud noises, abnormal light cycles, tumors, lack of nesting material, and malnutrition. Female rats can abandon, abort or even eat the babies if they don’t receive an adequate supply of water and food, face overcrowding in the cage, don’t have nesting material, or give birth to ill kittens.

Problems during birth might also arise. These are found more often in rats older than 6-8 months, especially if this is their first time giving birth. You can diagnose the problem if the birth process has begun, but no baby has been delivered within a 120-minute time frame. 

It’s likely that the baby is stuck across the bottom part of the rat’s Y-shaped uterus. You may massage the female’s abdomen. If it doesn’t help, try applying a little bit of baby oil on the birth canal and pulling the pup out using forceps. Oxytocin helps deliver the next couple of babies. 

In case the mother retains one or two unborn fetuses, she might expel them or reabsorb them. Provide her with antibiotics to prevent infection in such an instance.

If the mother rat dies after giving birth and leaves behind surviving babies, find a nursing mother to foster them. Do the same if the mother, for some reason, refuses to nurse.


Rats, just like other mammals, need a male to produce healthy offspring. It’s not entirely impossible for rats to get pregnant without a male, but it requires a great knowledge of genetic engineering, high-end experimental laboratory equipment, and a number of trials and errors. Even then, it may result in infertile and unhealthy offspring.

If you are ready to take responsibility for a pregnant rat, and later, her babies, then you can adopt a healthy male. To induce pregnancy, you also need a sexually mature female, in the age between 5 weeks and 18 months (though 4-5 months is the preferred age). 

You can keep both rats in one cage when they’re going through their heat cycles, and it’s highly likely that the female will be pregnant the next day. After a 21-25 day gestation period, the female rat will produce a litter of 6-13 pups.