Rats may have a reputation for being dirty pests, but baby rats are actually quite cute and fascinating little creatures. If you’ve ever wondered what newborn and juvenile rats look like as they grow, you’ve come to the right place.

In short: baby rats are born pink, hairless, and with their eyes closed. Over the first few weeks of life, they grow fur and open their eyes. Baby rats look very similar to adult rats, just on a smaller scale.

Appearance at Birth

When baby rats are born, they have a distinct set of characteristics that differentiate them from adult rats. Let’s take a closer look at the appearance of baby rats at birth.

Hairless and Pink

One of the first things you’ll notice about baby rats is their lack of fur. They are born completely hairless and have a soft, pink skin. This is because their fur hasn’t developed yet. As they grow, their fur will start to grow in, and you’ll be able to see the color and texture of their coat.

Eyes Closed

Another notable feature of baby rats is that their eyes are closed at birth. Unlike many other animals, baby rats are born with their eyes shut. It takes about 10 to 14 days for their eyes to open and for them to start seeing the world around them.

Large Head and Feet

Compared to their bodies, baby rats have relatively larger heads and feet. Their heads are proportionally bigger than those of adult rats, and their feet may appear oversized as well. This is because their bodies are still growing and developing, and these features will eventually become more proportionate as they mature.

Birth Weight and Size

On average, baby rats weigh between 5 and 7 grams at birth. They are tiny and delicate, fitting comfortably in the palm of your hand. Their size may vary depending on the breed and the size of their parents. As they grow, they will rapidly gain weight and reach their adult size within a few months.

For more detailed information about baby rats, you can visit the The Spruce Pets website, which provides comprehensive guides on rat care and behavior.

Early Growth and Development

When it comes to the growth and development of baby rats, there are several key stages to be aware of. These stages are crucial for their overall well-being and understanding what to expect during each phase can help rat owners provide the best care possible.

Fur Growth

One of the first noticeable changes in baby rats is the growth of their fur. Typically, baby rats are born hairless and their fur begins to grow in within the first few days of life. It starts as a thin layer of fuzz, but gradually becomes thicker and denser as the rats grow.

By the time they are around two weeks old, most baby rats have a full coat of fur.

Eyes Open

Another important milestone in the early growth of baby rats is when their eyes open. Newborn rats are born with their eyes closed, but they typically begin to open them when they are around 10 to 14 days old. At first, their eyes may appear cloudy or hazy, but they quickly clear up.

Once their eyes are fully open, baby rats become more aware of their surroundings and start exploring their environment.

Rapid Growth

Baby rats experience rapid growth during their early weeks of life. In fact, they can double their birth weight within the first seven to ten days. This rapid growth is supported by the mother rat’s milk, which is highly nutritious and provides all the necessary nutrients for their development.

It’s important to ensure the mother rat has access to a balanced diet during this time to support the growth of her babies.


As baby rats continue to grow, they eventually reach a stage where they are ready to transition from milk to solid food. This process is known as weaning. Typically, baby rats are weaned between three to four weeks of age.

At this point, they are able to consume a variety of solid foods, such as fruits, vegetables, and specially formulated rat pellets. It’s important to introduce solid foods gradually to avoid digestive upset and ensure the baby rats are receiving proper nutrition.

Understanding the early growth and development stages of baby rats is crucial for their overall health and well-being. Providing appropriate care and nutrition during these stages can help them grow into healthy and happy adult rats.

1-4 Weeks Old

During the first four weeks of their lives, baby rats go through several important milestones in their development. Let’s take a closer look at what these adorable creatures are like during this period.

Fully Furred

By the time baby rats reach one week old, they are usually fully furred. Unlike other mammals, rats are born without any fur, and it takes about a week for their fur to grow in. The fur provides them with the necessary insulation and protection as they start exploring their surroundings.

Improved Mobility

As baby rats grow older, their mobility greatly improves. At around two weeks old, they start taking their first wobbly steps and begin to explore their environment. By the end of the fourth week, they become much more agile and are able to navigate their surroundings with ease.

Teeth Growth

During the first four weeks, baby rats also experience significant growth in their teeth. Rat pups are born with their first set of teeth, known as milk teeth. These teeth are small and sharp, allowing them to nurse from their mother.

As they grow, these milk teeth are gradually replaced by their permanent teeth. By the end of the fourth week, their permanent incisors and molars start to emerge.

Social Interactions

One fascinating aspect of baby rats’ development is their social interactions. From an early age, they begin to engage in play behavior with their siblings, which helps them develop important social skills. This playtime includes activities such as chasing, wrestling, and grooming each other.

These interactions are crucial for their social development and help them establish hierarchies within their litter.

Understanding the different stages of a baby rat’s development is not only fascinating but also important for those who own or work with these animals. By knowing what to expect during each stage, it becomes easier to provide them with the appropriate care and attention they need.

4-8 Weeks Old

During the period of 4-8 weeks, baby rats go through significant growth and development. Let’s take a closer look at what happens during this stage.

Reaching Adult Size

By the time baby rats reach 4-8 weeks old, they are well on their way to reaching their adult size. At this stage, they have already grown significantly and are close to reaching their full size. It’s important to note that the exact size of a baby rat can vary depending on its breed.

Gender Differences

One interesting aspect to note is the gender differences that start becoming apparent during this period. Male rats tend to be slightly larger than their female counterparts, with a more muscular build. Female rats, on the other hand, have a more slender and agile appearance.

Playing and Exploring

Baby rats at this age are full of energy and curiosity. They are constantly exploring their surroundings and engaging in playful behavior. You may notice them climbing, running, and even chasing each other around.

This is an important stage for their physical and mental development, as they learn important skills and build their coordination.

Continued Development

Aside from physical growth, baby rats continue to develop their senses and cognitive abilities during this period. They become more aware of their environment and start to learn basic social behaviors from their littermates and mother.

It’s also during this time that their teeth start to grow, and they begin to learn how to eat solid food.

It’s important to provide a safe and stimulating environment for baby rats during this stage of their development. Ensuring they have plenty of toys, opportunities for play, and a balanced diet will contribute to their overall health and well-being.


In summary, baby rats are born hairless and develop fur over their first few weeks of life. They open their eyes after about 2 weeks and quickly gain mobility. Over 1-2 months, baby rats grow to reach adult size and become curious, playful juveniles.

Their continued development and interactions are fascinating to observe.

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