Start Here: Rat Basics for Pregnancy, Birth, and Babies


In these photos, my amazing mom rat, Maizie, a baby herself, helps us learn about Oops litters. She was pregnant when I got her, unbeknownst to me.

Maizie did not look pregnant until the day before she gave birth (6 days after I got her).  When I did the math, she had gotten pregnant at the earliest possible age: 5 weeks.

Useful material to help Oops Human Parents starts below the photos.


This was 3 days before Maizie gave birth. I did not suspect pregnancy. Scroll down to see her transformation.

Subjects covered below:

Is your rat pregnant? Leading up to the birth.

The option of spaying the pregnant rat to abort the babies

Giving birth

Emergency birthing problems

How soon after giving birth can New Mom Rat get pregnant again? The same day!

Complications if Mom Rat is pregnant post-partum

Once Mom Rat has given birth

If Mom Rat won't nurse the babies, or, raising an orphan rat

Nutrition for baby rats

Socialize (tame) the babies immediately

Wean and sex baby rats no later than 5 weeks of age

What to do with 6-20 oops baby rats



Do you unexpectedly have a pregnant, "Oops!" female rat?

Are you scrambling to figure out the basics, what to do, what to watch for, and how to help? On one of the rat groups a rescuer of rats found herself in just that spot. She sought help and several people provided great, useful information. This inspired JoinRats to combine critical information for any person who finds herself in the same situation.

IMPORTANT! These information pages are not designed to help someone deliberately breed rats. While serious, science-based breeders have a place in the promotion of the domesticated Norway rat, it is very difficult to breed rats well. The average pet rat owner does not possess the skill or knowledge to breed rats effectively, taking into account health and genetics. Please consider adopting your rats from a rescue, shelter, or adoption agency. Thousands of pet rats of all ages are abandoned, neglected, or abused, and need a loving forever home. Rats from "Oops" litters can make fabulous pets. Please leave any deliberate breeding to the few and far between expert rat breeders.

With that in mind, these pages aim to help the inevitable human who may adopt a young female rat and discover she is pregnant, or whose female rat escapes and visits the males' cage. There are many reasons humans find themselves with an "Oops" litter, and those folks need help to cope with the entire process of pregnancy, birth, and babies. Oh my!

Is your rat pregnant? Leading up to the birth.

Here are some facts on pregnant rats, from Rodents of Unusual Sweetness. [UNDER CONSTRUCTION]. First, The Ratty Facts of Life: Sex Ed 101 for Randy Rats and Their Confused Owners: [UNDER CONSTRUCTION].

Second, Pickles and Ice Cream or She's Having My Baby, er, Babies: [UNDER CONSTRUCTION].

The option of spaying the pregnant rat to abort the babies.

By Lindsay Pulman

Do not spay past one week after breeding. In the second week, the blood vessels that feed the uterus will be developing a lot, and cause a lot of bleeding, risky for the Mom. In the third week the mammary glands will be getting milk, and also developing lots of blood vessels,even more risky for the Mom, for bleeding out and also will get milk into the incision and abdomen. This is not something you want to do. If you can't pin down the exact breeding date then plan on raising and adopting out the litter.

Also, this depends on your personal beliefs and feelings. I used to be pro-choice, am now pro-life. I don't think these little lives should be ended. We humans are the smart ones so we need to take responsibility and take care of those little ratties.

If you can keep the litter, and have enough funds and enough room, there is nothing more delightful than living with a family of rats. The Mom gets to spend the rest of her life with her daughters, the daughters get to spend their entire lives with their wonderful Mom. The boys can spend their lives with brothers. The boys almost always work out long term. Occasionally a super Alpha develops, and you can neuter him and re-introduce him.

I rescued a family with two breeding females and a male, and their pups, and I can't tell you how gratifying it was to neuter and then successfully introduce the father rat (Angelo) to his 6 month old sons, and watch them interact, and bond, and form a father and son family. They adored each other. I have had only one oops litter (and my other family affairs occurred when I rescued a female and she turned out to be pregnant). The families have given me so much pleasure and love, I wouldn't have missed it for the world!

Alternately, you can lovingly raise the pups to adoptable age and make the effort to find good homes.

I cannot state strongly enough that euthanizing pups after birth is just the wrong thing to do. I have been there once, done that, and all the little lives that never got to enjoy the world haunt me to this day. I regret that more than almost anything I have ever done wrong in my life. Make the effort needed to either keep or place the pups.

Giving birth

Again, from Rodents of Unusual Sweetness. The Miracle of Birth or Quick! Boil Water!!! [UNDER CONSTRUCTION].

How soon can the new mom get pregnant again? Almost immediately! contains all the facts on domesticated and wild Norway Rats. How soon can a new-mom rat get pregnant after giving birth? Here's the section on that subject from If you roam and want to return to the page I've listed below on "How soon can female rats conceive after giving birth?", click here,

"How soon can female rats conceive after giving birth?"

"Postpartum conception is a subject of great interest to rat owners. For example, some new rat owners are surprised by an unexpected litter. Their presumed same-sex pair of rats is actually a male-female pair! Such owners wish to know how quickly they should separate their rats to avoid another litter."

"How soon can a female conceive another litter after giving birth?"

"The answer is soon! Females go into heat between about 10 and 24 hours after giving birth. Specifically, females go into heat on the first evening that is at least 10 hours after giving birth (Gilbert et al. 1985). This phenomenon of coming into heat shortly after giving birth is called postpartum estrus."

"However, eggs fertilized during a female rat's postpartum estrus may not implant right away, due to a lactation-induced delay (Mantalenakis and Ketchel 1966). Female rats that conceive during their postpartum estrus may therefore go through an extended gestation of about 32 days (+-1 day) rather than the normal 21-22 days (Mennella and Moltz 1988). To the rat owner, it looks like the female conceived about 10 days after giving birth, when in fact she conceived shortly after birth but simply had a longer pregnancy than normal."

"After the postpartum estrus, the female rat does not come into heat again until after the weaning of her litter. This estrus is called the postweaning estrus and it occurs about 29 days after a female rat gives birth (Mennella and Moltz 1988)."

Complications if Mom Rat is pregnant post-partum

By Danielle Smith:


Emergency birthing problems

From Rodents of Unusual Sweetness.[UNDER CONSTRUCTION].

Once Mom Rat has given birth

By Danielle Smith

From Rodents of Unusual Sweetness. (Permission to host this information is granted to You can visit a larger set of their information framed in this gallery on JoinRats: What to Expect When Your Rat Is Expecting - on Rodents of Unusual Sweetness

This is text on top box of the stain glass window box.

Depending on the comfort level of the dam, kits can be held immediately after birth. There is a right way and a wrong way to do this.

Get her attention, then when she gets off the litter, pick Mom up, give her a favorite treat, and put her in a travel cage to enjoy it while you handle her kittens.

Before we go into kit handling details, we need to discuss how to handle their mother. Remember to put the kits back and arrange the nest as the dam had it BEFORE putting mom back! This will reassure her that she can trust you and make her less nervous about leaving her nest. She'll be able to smell you on the kits and the nest, but if you are careful and faithful in this detail of showing respect for the dam and her space, it will prevent her from becoming upset by your interference and will actually strengthen your bond with her.

Remember, they can't keep themselves warm until they are about two weeks old. For the first week, keep handling sessions down to two to five minutes. You can have several handling sessions per day, but remember not to bother mom too much or Mom will come to dread her breaks and become defensive and aggressive. For the first week, give her at least two hours between handling sessions to nurse and bond with her kits. Three to four hours is optimal, by then the doe will be tired and will appreciate a few minutes of extra attention and a place to enjoy her treats unmolested.

During the second week, the kits' fur will be coming in. They will grow exponentially and can handle a minute longer away from Mom each day. Start with six minutes at eight days and by their two week birth day, you should have them worked up to fifteen.

Once they are two weeks old, they can keep themselves warm and potty with out having to be stimulated, so here you have some freedom. Handling sessions can go up to thirty minutes on their third week of life.

Once they are past three weeks old, you can have them away from their dam for several hours. (And believe me, she will appreciate the break!)

Kits wean between four and five weeks of age. There is no harm in removing them at four weeks. Nor is there harm in letting them stay with mom until they are five weeks old.

Rats are sexually mature between five and six weeks, so NEVER let the litter stay with mom past five weeks! Does can stay, of course, but you'd better be absolutely certain that the kits with mom are does!

Bucks between five and six weeks old can get does pregnant and does between five and six weeks old can get pregnant.

So mark their birth date on the calendar and keep track.

If Mom Rat won't nurse the babies, or, raising an orphan rat

This section has two authors. First, JoinRats is pleased to host, with permission, framed material from The American Fancy Rat and Mouse Association (AFRMA), here: Caring for Rat & Mouse Orphans - on AFRMA

Second, notes from Lindsay Pulman and Lisa Dunsey:

Call the pet stores to see if any of them have nursing moms with young pinkies, as rats will take in other rat babies very easily. That may be your best option - either buy the nursing Mom with the idea that you can return her with her own pups, or see if they will take in your pinkies and place them with the nursing Mom.


Some females will not lay on the babies and nurse when there is anyone watching. we had one like that - she could hear us coming in the room and would, in a flash, be on top of the box guarding it. We thought she was never on the pups - but, on day three, we picked her up out of there with a towel she was not friendly) and checked each baby, and they all had little crescent milk bellies.

Are you sure there are no milk bellies? if not, get to the store asap and get human soy based infant formula or go to the pet store for kitten milk replacer, get the kind in the small can that is already liquid. All pet stores carry it.

You will need:

  • 1 ml syringe or a small dropper (1 ml syringe preferred, the drops are smaller).
  • A box lined with a towel, and a liter plastic pop bottle that you can fill with hot water - cover with a thin towel to allow heat through.
  • Some Q-tips and a small bowl of warm tap water.
  • Some Kleenex

Warm a small amount of kitten milk replacer or human soy-based infant formula in the microwave until JUST skin temperature. NO warmer than that.

Take a baby, and hold her in the palm of your hand, curled around her, and drop a single drop of milk into one of the creases, near her mouth - she must suckle the milk from your skin. An alternate position is to hold the baby in your fist, upright, head up, with the mouth near the top of your curled index finger - and place one small drop of milk at a time on the flesh of your index finger, right by her mouth. Once they learn the milk is there they will eagerly suckle it from your skin. The excess can just run down the inside of your hand.

NEVER TRY TO PUT THE MILK DIRECTLY INTO THE BABIES MOUTH WITH THE SYRINGE OR DROPPER. They easily inhale milk if you try this, and once milk gets in the lungs, you will have a serious pneumonia, the baby will die. Also be careful to not get milk over the nostrils, they don't know to sneeze out, and may suck it in - same result, pneumonia. Let the baby suckle it from your skin which is almost like them nursing on that tiny nipple on Mom's skin.

At the beginning each baby hopefully will eat between .1 and .2 ml, a very tiny amount. You will be doing well.

They must be fed every 2 hours or as close as you can get it, and set the alarm to allow 3 hours of sleep and then get up and feed again, for the first week. They will gradually increase the amount they are eating at each feeding.

After each feeding, you MUST moisten a Q-tip in the warm water and gently roll and stroke that Q-tip over the genital area - both the urinary opening and the anal opening, to stimulate peeing and pooping. You will be able to tell instantly that you have succeeded, the Q-tip will turn yellow.

At the end of the feed, if you can see some milk in the belly you will be doing okay.

Keep them warm, very important. If they are cold, they will not even digest what they take in . Take the whole litter out at one time, and nestle them under towels next to the liter water bottle. Keep track of who was fed and who needs it - place one bunch on one side of the bottle, the other bunch on the other side.

Keep the cage very warm and dark. Gallon plastic jugs filled with HOT water, around the outside of the cage, then drape towels over the cage. Always put the litter back in the nest, together, after feeding.

Mom may very well turn into a good Mom if you can just keep them alive in the meanwhile. If not, with enough dedication and doing the procedures right, you will be able to hand raise all of them yourself. I have done it twice.

During the second week, you can back off the feedings a little - feed every 3 ot 4 hours all day long, and get up once during the night.

If you take them out for a feed, and they have mild bellies before you start, Mom may be feeding them!

Don't give up. Give it a try, it is one of the most rewarding things to do ... save those little lives.

Additional note from Lisa Dunsey:

The only thing I would add is when Lindsay actually was here at my shelter demonstrating the exact technique she describes in this e-mail on how to feed the babies, Lindsay had a little one that after eating didn't make her waste on the Q-tip. So they don't necessary do it every time you try to get them to go to the bathroom. Had I not seen Lindsay doing it and then the little one not wanting to go potty I would have thought I did something wrong. Since it was Lindsay and she even said something about the baby not wanting to potty I knew for future feedings of the babies that they may not go even with help from us with the Q-tip. So every feeding I would do the Q-tip after feeding but not necessarily would the babies make waste.

Nutrition for baby rats [PLACEHOLDER]


Nutrition for baby rats [PLACEHOLDER]


Socialize (tame) the babies immediately


After birth: Baby rats grow!

JoinRats is delighted to host material from a few sites with excellent photographs detailing the growth of baby rats, and sharing many useful facts, including The American Fancy Rat and Mouse Association (AFRMA), Ratguide, and Rattie World O' Comfort. Here you can see what your baby rats should look like as they age from birth to five weeks of age:

Birth to Weaning - Rat Guide (Weeks One through Four)

Baby Rat Development - AFRMA (10 hrs, 36 hours, 5 days, 11 days, 14 days, 2.5 weeks, 4 weeks, 6 weeks)

Pictures of the Pinkies - Rattie World O' Comfort (Several photographs every day, Days 1-24)

Wean and sex baby rats no later than 5 weeks of age!

The rules:

  • Sex the boys and girls, and remove the boys from their mother and sisters, by 5 weeks of age. Not one day later!
  • Baby girls can remain with Mom longer, and will benefit from additional nursing time.
  • Unless you are an expert, well trained, with lots of experience, sexing baby rats can be very difficult. If you make a mistake, you may have a pregnant baby female rat at age 5 weeks.
  • Study the anatomy of boy and girl rats, and review all the photographs offered on the several sites below. Learn the 'shades of grey' issues that may confuse you. Consider consulting an expert even if you feel certain of the baby's sex.
  • You can wean babies as young as 4 weeks without a problem, except that the babies would benefit from nursing as long as possible. Anything you can do to ensure good health will help in the long run. It is technically possible to wean the babies at age 3 weeks, but this is not recommended.
  • JoinRats is pleased to host framed photographs and instructions from five excellent sites (listed in alphabetical order). Click each and view many detailed photographs and comparisons. Improve your skill at sexing baby rats, and do it before your "Oops" litter reaches 5 weeks of age:
    1. Sexing Rats: Sexing Baby Rats 101 - AFRMA. Simple line drawings, also photos of mice, some general photos of rats.
    2. Sexing Rats - Alpha Centauri Stud. Photos showing you can determine the sex at 2 hours old. Label point out the important body parts. Photos cover 2 hours of age, 4 days, 9 days, 14 days, and 5 weeks.
    3. Sexing Rats: Litter Journal - Sexing Babies - Curiosity Rattery. Excellent close-up photos of 1-day old rats, 5 days, 10 days, 2 weeks, 3 weeks, 4 weeks, 5 weeks, with circled and lined important body parts.
    4. Sexing Rats - RatRaisins shows us how to extrude the penis as opposed to the vagina, and what you see when you try. In addition, sometimes sexing rats is very difficult. RatRaisins talks through the difficulties and provides solutions to the ancient question, "Is this rat a girl or a boy?"
    5. Sexing Rats: Is This Rat a Boy or a Girl? - RattyRat. A few clear photographs with line drawings to distinguish the sexes.

What to do with 6-20 baby rats [PLACEHOLDER]



The information on this site is not designed to aid in deliberately breeding rats, assist a rat giving birth, or solve rat birthing problems. This information is not sufficient to properly raise baby rats, or to correctly sex baby rats. If you suspect your rat is pregnant, please see a Veterinarian to determine a diagnosis, and for guidance on how to proceed. Seek expert assistance to determine the sex of any baby rats, and to separate the males from their mother and sisters, no later than 5 weeks of age, and keep in mind that mistakes in sexing still occur, and that pregnant 5-week old babies may be one outcome of any new litter of rats.

JoinRats assumes no responsibility for the misuse or misunderstanding of the information here, and makes no guarantees with respect to the issues related to rat pregnancy, the birthing process, or the care of baby rats. The information offered is strictly for educational and informational purposes only, and does not replace qualified care by a Veterinarian.

Also, while serious, science-based breeders have a place in the promotion of the domesticated Norway rat, it is very difficult to breed rats well. More importantly, the average pet rat owner does not possess the skills to breed rats effectively. For the average pet rat owner, please consider adopting your rats from a rescue, shelter, or adoption agency. Thousands of pet rats of all ages are abandoned, neglected, or abused, and need a loving forever home. Rats from "Oops" litters make fabulous pets. Please leave any deliberate breeding to the few and far between professional rat breeders.

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