Pet Rats/Obese rats


I have two albino males. They have the same diet but one is over 2 pounds and the other is just over two. They are close to the same age and don't seem to have any issues with dominance. I feed them Regal Rat food instead of blocks and small amounts of people food. They have never had much free ranging until recently. I have set up an area and let the have a couple hours at night. Is there anything else I can do? I don't want the smaller guy to lose weight because he's already lean... Thank You! Candice


Thank you for your question.

There are many reasons into why a rat might weigh more than the other ,even when they are fed the exact same thing.

Here are just a few reasons I can think of:
1. One might be more dominant than the other and is able to 'bully' the other out of the food bowl. Even rats that naturally get along might have some food issues.

2. Genetics. One might have a faster metabolism than the other, causing weight to be shed more quickly than the other. Even different strains of rats vary in weight, as seen in different strains of laboratory rats. Some strains are more susceptible to obesity than others.

3. One might be more active in the cage and/or during free range time, causing weight to be shed more easily than the other.

4. Age. Younger rats weigh less than older rats as they are constantly moving whereas older rats begin to slow down with age.

If you don't already, try having two separate food bowls available, on different levels or areas of the cage. This will help if there is any dominance issue. I would check to see if they are stashing food anywhere in the cage, such as in a hammock, in a tunnel, etc. Perhaps someone is into late night snacking, LOL!

Rats, like humans, vary in weight naturally. A female adult rat has an average weight of 225 to 400 grams where as adult males average between 250 to 550 grams. As long as your rats are within this range, I would not worry too much. Just be sure any "people" food and other treats you are giving them is healthy, low in fat, and high in nutrients.

I hope that helps!  

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Shawna Laufer


Nutrition has always been an interest of mine as well as creating stimulating environments for rats. I conduct product reviews on my blog so I can take questions regarding products marketed or intended for rats. Other questions regarding basic husbandry, feeding, grooming, and other pet rat care will be accepted. I have very little breeding experience so I would not be able to answer much in the ways of breeding or genetics questions. I can help with some basic health care questions but am not a vet and always suggest contacting your vet for serious inquires.


I have over 13 years of experience with pet rats, having worked in several pet stores, as a veterinary tech assistant, and with my own pet rats. I run a highly regarded blog on the subject of pet rat ownership ( with a corresponding YouTube channel and Facebook page. I have been and always will be open to questions and comments.

A photograph of my lady rat's cage is being published in Worth Publishers' college textbook "How Children Develop, 4e" by Robert Siegler, Judy DeLoache and Nancy Eisenberg on the subject of how complex, stimulating environments and how they relate to the brains of rats.

I have some college experience, but not in the field of animals. I completed the majority of an at-home Veterinary Technician course which I was unable to complete due to financial reason. The majority of my knowledge on rats have come from personal experience, conducting my own research with the help of published medical studies and journal, the internet and through other knowledgeable 'rat people'.

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