Are you the proud owner of a juvenile pet rat?  Do you want to know how much they are going to weigh so you know the size of the cage to get?  

Male pet rats do weigh more than a female pet rat, which is something most everyone already knows.  Maybe you feel your pet rat is overweight?  

Average Weight of a Pet Rat

It is important to keep track of the weight of your pet rat to make sure that they are not underweight or obese.  On average, the female adult pet rat weighs between 0.7 and 1 pounds while the male pet rat weighs between 1-1.4 pounds.  If you make sure that your pet rat is given the right food and treats along with exercising, they can keep a healthy weight.  When a pet rat is born, they only weigh between 6 to 8 grams and by the time they hit 6 months, they are considered an adult rat.

Nutrition Tips

The best nutrition tip you can receive is to make sure that you are feeding your pet rat food that is made specifically for them.  This is important because depending on the pet rat, each pet rat may have a different diet.  One example of the wrong food to buy is hamster food. 

Many think that it is okay to buy hamster food to feed to a pet rat but that is not true.  A hamster’s food has more calories than pet rat food plus the seeds in a hamster’s food are too fat for your pet rat to consume.  

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When checking out pet rat food, look for pellets that say it is for pet rats.  This way you know that they are getting all the nutrients they need.  The pellets are all the same so your pet rat will eat every single one.  Make sure that you do not get just the pellet and seed mixture.

After all, they will just eat what they want because they are a picky eater.  This means that they may be missing out on some of the important vitamins and nutrients they need.

You also need to make sure that they are getting fresh vegetables and fruits each day.  It makes meals is interesting and is healthy for them.  Your pet rat, as humans, gets tired of the same thing every day so give them some of their favorite treats occasionally.  This could be carrots, pieces of apples, broccoli, etc.  It all depends on the pet rat as each one is different.

You should try to make sure that you give your pet rat fresh greens daily.  Most pet rats love kale.  Make sure that your pet rat has freshwater, which is essential to help fight obesity.  You should use a water bottle to prevent them from getting waste or food into the water.

Foods to Help Your Pet Rat Gain Weight

If your pet rat is losing weight you should take them to the veterinarian to make why this is happening.  If it is just because they are having trouble gaining weight, you can try to feed them high protein food like avocado or eggs.  There are also supplements and vitamins you could give them.  

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Overweight Rats

In order for your pet rat to stay at a healthy weight, you need to watch what they are eating because they will eat just about anything.  Keep things that you do not want them to eat in a cabinet or someplace they cannot get into.  The main reason that most pet rats are overweight is that they are not active enough and/or eating too many fatty foods.  Sometimes pet rats will steal food from another pet rat so one is getting too much food while the other one is not.  With two or more rats in the same cage, you should have a couple of bowls of food in the cage placed in different places so they have more than one place to go eat.

You also should make sure that you are giving them the right treats.  You should avoid giving them sugary and fat foods, including fast food, cookies, other sweets, and seasoned foods.  They may taste delicious to your pet rat but they have almost no nutritional value.  Their diet should be low in fat and high in fiber.

If your pet rat is overweight, to get them back to a healthy weight you need to make sure that they are staying active.  They get bored if they are just playing by themselves, even if they have interactive toys.  This is why you should always have at least two pet rats.  It will give them someone to play with. 

Make sure that you also have interesting and different toys for them to play with but not too many at a time in their cage.  It is recommended that you have at least six different toys and put only one or two at a time in the cage, changing them every week. 

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Some of these toys can include ropes, climbing toys, and wheels.  An exercise ball that they can roll around in is a good exercise toy.


  • You must keep your pet rat at their right weight to keep them healthy.
  • A female pet rat should weight no more than one pound and a male rat should weigh no more than 1.4 pounds.
  • If you are using rat laboratory pellets make sure that you measure them out correctly and not just dump a random amount in a bowl
  • Avoid unhealthy treats
  • An overweight pet rat can develop health problems like diabetes or cardiovascular issues.
  • Do not feed your pet rat seeds as they will pick and choose what they want.  They can have them as a special treat.
  • You should weigh your pet rat weekly so you can see if you need to do any adjustments on their food intake and if they are gaining or losing too much weight.
  • A healthy pet rat is a happy pet rat.
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Hi! I'm Anna and I´m a certified cynologist (KAU, ACW). Expert, blue cross volunteer, owner of Chinese crested kennel "Salvador Dali" and breedless friend called Fenya. "I can't imagine my life without dogs and I totally support the idea #AdoptDontShop".