Rat Food Myths: The Facts About Foods To Avoid

From staple diets to treats to what foods are a no-no, a rat’s diet is easily one of the most talked about subjects in rat care. What complicates things is that the internet is full of confusing and often overly exaggerated information about it. Doing just a minimal Google search on the foods to avoid giving rats immediately returns list after list of fact AND fiction from well-meaning rat lovers.

Consider The Information Source

The main problem is that most of the information these sites are regurgitating is based off of old lab studies done on rats. These studies are usually done to learn what’s safe for people, not what’s safe for rats. Lab tests often give rats exorbitant amounts of different foods that far exceed any reasonably sized portion. So, yes, in lab conditions with extreme quantities fed, rats often died. It doesn’t mean that your pet rats will be harmed if given tiny amounts of the same foods.

The other issue I’ve noticed is that many people creating these lists confuse rats with dogs. They add in items that dogs can’t eat. In reality, these items are perfectly safe for rats. For instance, the number of times I’ve read someone online proclaim that grapes/raisins and chocolate are toxic to rats is quite staggering. Are they in fact toxic for rats? Nope, not at all! But they definitely are for dogs.

Grapes are actually a perfectly healthy treat to give rats. My rats get some weekly. And dark chocolate actually has medicinal benefits and can act as a bronchodilator to help rats with respiratory issues. My veterinarian even “prescribed” dark chocolate chips for some of my sick rats (one given four times a day during respiratory treatment). Consult your vet before using any food as a treatment. Note that milk chocolate offers no real benefits and contains sugar your rat doesn’t need, so skip it.

So, how do you know what foods to actually avoid giving your rats? The internet is full of misinformation, and it’s difficult to find concrete answers sometimes. Even after three decades of researching this topic, I still find it rather confusing. But I’ll share everything I’ve learned through a lot of time and effort and talking to other rat experts.

Potentially Toxic Foods

There are a few well known foods that rats shouldn’t eat. Especially because a few of them are unsafe for humans as well. For the most part, what isn’t safe for people isn’t safe for your rats either.

• Avocado skin and pit (the pulp/flesh is OK)
• Apple seeds
• Blue cheese
• Raw or dried beans and legumes
• Raw sweet potatoes
• Raw squash
• Green potato skins and eyes
• Raw peanuts

The pulp/flesh of the avocado is safe for rats and actually a healthy treat, especially for sick or underweight rats. But never let your rats eat any of the skin or eat off the pit. They contain an oil-soluble fungicide called persin, which animals are sensitive to.

For the same reason humans shouldn’t eat most raw beans and legumes, rats shouldn’t either. They contain lectins that our bodies can’t break down and can lead to sickness — and sometimes even death. If you’re ever unsure of what beans your rats can eat and how they should be safely prepared, research how humans should eat them.

Raw peanuts can contain mycotoxins that are naturally found in mold and are unsafe for rats. While roasted and unsalted peanuts are safe, they are very high in fat and should only be given occasionally in very sparing amounts.

Green potatoes can contain the toxin solanine, which can cause digestives issues and illnesses. Both humans and rats should not be eating green potato skins or eyes. Research how to tell if your potatoes should be thrown out.

I consistently read that the mold in blue cheese is highly toxic to rats and is even used to kill wild rats and mice. I can’t find any real scientific studies on this myself, but it seems prudent to avoid giving your rats. I mean, do they need blue cheese? No. More common cheeses like cheddar and Monterey jack are safe, but their high fat content means it should only be offered occasionally and in tiny portions.

Foods Best Avoided

There are foods that won’t outright kill your rats but aren’t necessarily healthy for them either. Avoid offering them.

• Sugary foods
• Fast food
• Fried food
• Highly processed food
• Sugar substitutes
• Foods high in sodium
• Sticky foods (see Choking Risk)
• Carbonated beverages
• Alcohol
• Caffeine
• Dried corn
• Citrus peel (see The Myth About Citrus)
• Tap or fluoride-treated water

For obvious reasons, never give your rats foods high in sugar, fat, salt, or anything highly processed or fried. Can you give them a nibble of a French fry or some ice cream every now and then? A teeny, tiny taste maybe, but this should absolutely not be a regular occurrence — no matter how much they beg for a bite of your fast food.

There’s a myth that carbonated drinks will kill rats and mice. This is unfounded, but due to the rat’s inability to burp or vomit, carbonated drinks aren’t exactly ideal for your rats either. Besides these drinks potentially making your rat feel really uncomfortable, they absolutely do not need any of that sugar or sugar substitute.

It is said that dried corn can contain toxins from mold. For this reason, it has been on the “do not feed” lists for rats for decades. In the past I was against this as an ingredient, but I’ve since learned that there’s a lot of conflicting data on whether it’s actually harmful to pets or not. And it’s in many of the most highly recommended commercial rat diets, even the ones specifically formulated for lab rats that require controlled diets and weight. So, I honestly don’t know what to say about dried corn, except that, if you feel uncomfortable giving it to your rats, then don’t. But it is perfectly safe to offer your rats a few kernels of freshly cooked corn, which they will love.

Choking Risk

Some foods are perfectly fine for rats to eat, but can cause a choking risk, especially when given alone.

• Honey
• Peanut or nut butters
• Overly soft dried fruits
• Mashed potatoes
• Soft, doughy bread
• Popcorn
• Chips
• Pizza crust

For instance, honey, dried fruits, mashed potatoes, doughy bread, and especially peanut butter can become too thick or sticky for rats and get stuck in their throat. Foods like this should either be thinned out or used as an ingredient in something else. I have personally witnessed a rat choke on peanut butter. He survived, but it was a horrific, frightening ordeal that no one should have to experience.

I’ve also had a rat choke on dried fruit before. It was a plump piece that was very soft and sticky. Allowing fruit like this to dry and harden a bit more makes a huge difference.

The food items on this list aren’t forbidden, but be really mindful when offering them to your rats. Seriously, never give your rat any type of nut butter straight from the jar!

The Myth About Citrus

For decades, rat owners have been warned against giving citrus fruits like oranges and mangos, or orange juice to male rats. This is due to the chemical compound D-limonene, which is found in the peel of citrus fruits. The warnings claim that the D-limonene from the peel could get on the fruit or in the juice and could cause kidney damage or cancer in male rats. Unfortunately, this was based on studies done where rats were fed D-limonene in extraordinarily large amounts that far exceed what even humans would ever consume. It is nowhere near comparable to the reasonably sized serving that a rat might be given. It is not fair to conclude that the tiny amount of D-limonene found in a rat-sized chunk of mango would have nearly the same effect on your rat as to what the lab rats were given over long periods of time.

For this reason, it is my opinion that citrus does not need to be avoided at all costs. I have given my boys small chunks of mango and oranges before. I do think, however, that it’s fair to keep citrus skin and peels away from your boys. They likely do not contain enough D-limonene to be an issue, but why risk it when your rat doesn’t actually need to eat it. To read more about this myth, check this blog.

Moldy And Spoiled Foods

This should go without saying, but just in case: do not give your rats anything that is moldy or spoiled. Just as it would make you sick, it will make your rats sick. And cutting off the mold doesn’t automatically make the rest of the food safe, because mold is not always visible. This is especially true in soft foods like bread, soft cheese, and fruits and vegetables, where the roots of the mold continue to burrow their way through. Yuck!

All of this may seem a bit daunting, but don’t worry too much. A lot of this is just basic common sense. If you’re ever in doubt about a food, just don’t give it to your rat. There are plenty of other things you can offer them. For a much more in-depth article on rat diets and knowing how to feed them, check out the diet article I helped co-write on the Rat Guide.

And if you’re ever worried that your rat has eaten something toxic, contact the ASPCA Animal Poison Control hotline at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661.