Helping to raise a litter of baby rats can be a rewarding experience. Not only will you get to see your beloved doe become a mother and watch her take care of her babies; you will also get to witness the development of a baby rat from day one. This exciting time brings up a lot of questions, though.
What does the normal development of baby rats look like? How can you best care for rat pups?
A lot of changes happen in a rat’s first few weeks of life so it’s important you know what healthy development looks like. We’ll give you a rundown of the first 6 weeks of your rats’ life and any issues that you might encounter along the way.
Raising Baby Rats
What Are Baby Rats Called?
Infant rats are called kittens or pups. The names aren’t gender specific. For clarity, I will refer to baby rats as pups throughout this article.
Rat Litter Size
Rats are known for having large litters that range in size from 8 to 18 pups1. You can expect a healthy female rat that’s been well-cared for to give birth to a litter that’s on the higher side of this range.
In most cases, mama rats are naturally well-equipped to care for this many babies and shouldn’t need too much assistance from you.
Female Rats Can Give Birth 17 Times In 12 Months
Female rats or does become sexually mature as early as 8 weeks of age1. This fact combined with a short gestation period of only 21-23 days, means they can produce 17 litters before reaching their first birthday. The bucks reach sexual maturity even earlier, often at 6 weeks of age1.
Therefore, it’s important to separate sexually mature does and bucks because not only will you wind up with more rats than you can handle, but this type of breeding is also dangerous for the rat’s health and well-being.
Don’t Handle The Pups For The First 7 Days
During the birthing process, it’s best to let the mother follow her own instincts and give birth alone. For the typical birth, you shouldn’t need to intervene but if labor lasts longer than 2 hours, you need to seek advice from a veterinarian.
It will be tempting to interact with the new pups right away but unless there is a problem you need to give mama rat and her babies space. The first 24 hours are crucial, but it’s best not to handle the pups at all during the first 7 days of their lives. Leaving the dam and her pups alone during this time will reduce the risk of problems, such as the mother rejecting a baby, or maternal cannibalism.
You can lure the dam out of the nest with a snack a day or two after the birth, to be able to count the pups (without touching them) and remove any stillbirths if necessary. If possible, refrain from cleaning the cage until the pups are a week old.
Common Problems In Newborn Rats
Pups That Aren’t in the Nest
Sometimes during the birthing process, the mother neglects to keep her babies in the same spot. This can be worrisome because pups need the warmth of their litter to survive.
If this happens while your doe is giving birth, it is totally fine to gently move the newborn pups into the mother’s prepared nest2.
No Milk Supply
Newborn pups develop a white band around their stomach known as a milk band. The appearance of this milk band is important because it will let you know if the pups are getting milk from their mother.
If you can’t see anything, there is a good chance the mother isn’t producing milk yet.
In cases where the milk supply is threatened, you will need to get a “foster mother” dam who is still producing milk or begin a strict hand-feeding routine.
In any case, ask a veterinarian for advice before interfering. Some breeders choose to breed two females at the same time, so that one can help out if the other dam is not producing enough milk.
Dam Seems Disinterested in her Pups
In some cases, the mother rat will fail to develop an attachment to her pups after birth. Instead of staying in the nest and nursing her newborns, the mother will leave her babies alone.
Try to keep the stress for the mother rat as low as possible – don’t handle her, and keep the environment quiet.
This is a heartbreaking thought, but you can help “force” a relationship by moving everyone into a confined space for a few days where the female must stay on top of the newborns3.
This will give the pups an opportunity to nurse and get the warmth they need to survive. In some cases, this could also lead to maternal cannibalism, but if you don’t have a foster dam lined up, it may be worth the risk.
Baby Rats: Week by Week
The first weeks of life for pups is exciting and full of change. They start their life reliant completely on their mother and in less than two months they’ll be weaned and ready to start their own young adult life.
Here is a rundown on the first 6 weeks of life. After 6 weeks, pups are fully weaned from their mother. At this point, they have reached sexual maturity and are now considered young adults.
One Week Old Rats
When you first observe a litter of pups, you will notice that they are completely pink and hairless. Their eyes and ear canals are sealed, and they are immobile. They rely on their whiskers for finding their mother’s milk and staying close to their siblings. A typical weight for a newborn pup is between 6 and 8 grams.
The baby rats will feed from their mother every 2-3 hours4. They also need her to regulate their temperature5, and to help them pee and poop – which she does by licking their bellies.
It will take a few days for pigment to become visible on their skin; at the end of this week you will start to have a good idea of their coat color and pattern. Around day 5, their coats begin growing, starting out as adorable patches of peach fuzz hair.
Two Week Old Rats
Week two is an exciting week of changes.
First, you’ll notice that their baby coat of fur is almost completely grown. A dramatic change from their newborn appearance last week!
The pups will begin developing their physical strength by standing and possibly taking their first steps towards the end of the second week.
You will also find that their outer ear canals are becoming more formed and open. At this point, pups are no longer considered hearing impaired and will start identifying low frequency sounds.
Three Week Old Rats
This is the week where you will notice that your precious babies are becoming independent balls of fluff!
At the beginning of the third week, pups will start opening their eyes6. Their vision is developed when their eyes first open, so they see their surroundings clearly. Rats aren’t known for their great vision, so they rely on their whiskers and excellent peripheral vision to guide them.
At this point of development, pups are ready to be offered softened solid foods like pellets that have been soaked with water and pieces of banana. They aren’t weaned yet and will still need their mother’s milk.
Four Week Old Rats
This week is a big week. The pups are nearly weaned and will soon become fully independent from their mother.
Your pups should be fully mobile by now, and you’ll notice that they spend most of their awake time playing and exploring their cage. Their movements might seem clumsy at first but with practice they will become more coordinated.
Their fluffy baby coats will begin to disappear during this week and will be replaced with their adult coat with apparent guard hairs and under hairs.
Five Week Old Rats
Now that the pups are almost fully developed, they should be getting most of their energy from solid food. They’ll burn this energy exercising their newly discovered independence to self-groom, dig, climb, and play with their siblings.
This week is important for developing social skills. It might sound silly, but rats are social creatures and need to learn social skills at an early age to exist with other rats peacefully. Pups learn everything they need to know from playing with their brothers and sisters.
Six Week Old Rats
This has been a busy six weeks! The babies have grown from hairless newborns to fully weaned and independent young adults.
At this stage, rats can become sexually mature1, so it’s imperative that the females and males from the litter have been separated. Luckily, this is when pups are ready to go to their new homes so that might help with the stress of separating genders.
While the pups have grown and are ready to be away from their mother, it’s important to monitor their growth for the next few weeks to ensure they are gaining a healthy amount of weight.
Now that you know what to expect when raising baby rats week by week, you should have a better understanding of their typical development and what they need from us.
Mama rats are usually enough when it comes to raising baby rats, but we will need to start helping during the third week by introducing solid food to their diet.
The baby stage is a quick one – so enjoy the cute little fluffballs while you can!
1. MSD Vet Manual. Breeding and Reproduction of Rats. 2020. https://www.msdvetmanual.com/all-other-pets/rats/breeding-and-reproduction-of-rats.
2. Beach FA, Jaynes J. Studies of Maternal Retrieving in Rats I: Recognition of Young. Journal of Mammalogy 1956;37:177-180. https://doi.org/10.2307/1376675.
3. Champagne FA, Francis DD, Mar A, et al. Variations in maternal care in the rat as a mediating influence for the effects of environment on development. Physiology & Behavior 2003;79:359-371. https://www.sciencedirect.com/science/article/pii/S0031938403001495.
4. Rat Fan Club. Raising Orphaned Rats or Mice 2017. http://www.ratfanclub.org/orphans.html.
5. Alberts JR. Huddling by rat pups: group behavioral mechanisms of temperature regulation and energy conservation. J Comp Physiol Psychol 1978;92:231-245. https://pubmed.ncbi.nlm.nih.gov/670452/.
6. American Fancy Rat & Mouse Association. Baby Rat Development from Birth to 6 Weeks 2015. https://www.afrma.org/babyratdevdaily.htm.
Nina has a degree from the Veterinary School in Zurich, with a special focus on microbiological research. Nina has a passion for sports, nutrition and the outdoors and she loves all pets, but rats have a special place in her heart. When she’s not working or reading and writing about all things related to pet health, she loves to travel and surf.
As a small animal veterinarian, Nina is your go-to expert on pet health and nutrition.