As nuts make a good occasional treat for your pet rats, you may wonder if this applies to peanuts, too. Peanuts aren’t actually nuts – despite their name – but belong to the family of legumes.
But is it safe to feed your pet rat peanuts? Are they really toxic, and if so, in what amounts?
In short: There are several concerns with feeding peanuts to your rats. Peanuts contain certain anti-nutrients, and they can be contaminated with aflatoxin. While an occasional peanut won’t kill your rat, there are better foods around for your mischief!
We’ve summed up all the research on peanuts and the safe amounts to feed for you in the article below.
Can You Feed Peanuts to Your Pet Rat?
Why Can’t Rats Eat Peanuts?
Peanuts are fairly high in protein and a great source of healthy fats1. They also contain various vitamins and minerals, such as biotin, copper, and folate1. Sounds great, doesn’t it?
On the other hand, peanuts also contain so-called anti-nutrients. For example, the anti-nutrient phytic acid binds to iron and zinc in peanuts, making these less available for digestion.
So, while peanuts may have good iron and zinc levels on paper, the bioavailability of these nutrients in the body will be much lower2. Anti-nutrients may also interfere with the absorption of other minerals and trace elements2.
Furthermore, peanuts and peanut products naturally contain mycotoxins. These toxins are produced by fungi that grow inside the peanut shell3 . Specifically, the mycotoxins most frequently found in peanut products are aflatoxins, which are produced by fungi of the genus Aspergillus4.
Aflatoxins can cause liver failure and have toxic effects on brain cells5,6. They’ve also been linked to the development of cancer7.
So, why aren’t peanuts an issue for humans, you may ask? They sometimes are, especially in warm tropic regions where more mold will grow inside the peanut shell during storage, and legumes tend to make up a large portion of the local diet3.
However, humans need to ingest quite large amounts of contaminated peanut products for the aflatoxins to cause problems. Much smaller amounts may be harmful to rats – so it’s safer to avoid peanuts and peanut products altogether or to at least limit them strictly.
Can Rats Eat Raw Peanuts in the Shell?
Raw peanuts have a higher concentration of aflatoxins than oven-roasted peanuts8. Offering peanuts raw is therefore not the best choice.
If you want to feed your rats peanuts, make sure you choose roasted peanuts and only give small amounts (one peanut per rat once per week, at most).
If you want to feed your rats roasted peanuts, make sure you choose a brand without additives, such as salt, spices, or sugar. These are all unnecessary and potentially harmful additions to your rats’ diet.
Usually, rats tend to love peanuts and peanut products. This should not be a reason to disregard their health, though – so limit peanuts to a very small and infrequent amount, or don’t offer them at all.
Peanut butter may also contain aflatoxins, and is also a choking hazard, so it’s best avoided completely.
What Kind of Nuts Can Rats Eat?
While peanuts are not nuts, we humans tend to think of them as such. So, you may be wondering if other nuts are best omitted from your mischief’s diet, too.
Basically all nuts that are edible for humans are safe for rats to eat. You can offer your mischief walnuts, hazelnuts, almonds, chestnuts, brazil nuts, pecans, and macadamia nuts. All nuts are high in (healthy) fat, though, so should only be fed as an occasional treat.
To Sum Up
Peanuts and peanut products contain anti-nutrients and can be contaminated by fungal toxins. While an occasional peanut here and there won’t kill your rat, peanuts don’t make a good choice of treat.
If you insist on feeding them, go with oven-roasted peanuts – but make sure you avoid salted, sweetened or spicy varieties. Only offer peanuts on rare occasions – or best not at all. Actual nuts such as almonds or walnuts make a much healthier treat for your mischief.
1. U.S. Department of Agriculture. FoodData Central – Peanuts, raw. 2019. https://fdc.nal.usda.gov/fdc-app.html#/food-details/172430/nutrients.
2. Lopez HW, Leenhardt F, Coudray C, et al. Minerals and phytic acid interactions: is it a real problem for human nutrition? International Journal of Food Science & Technology 2002;37:727-739. https://doi.org/10.1046/j.1365-2621.2002.00618.x.
3. Wild CP, Gong YY. Mycotoxins and human disease: a largely ignored global health issue. Carcinogenesis 2010;31:71-82. https://pubmed.ncbi.nlm.nih.gov/19875698/.
4. Lien KW, Wang X, Pan MH, et al. Assessing Aflatoxin Exposure Risk from Peanuts and Peanut Products Imported to Taiwan. Toxins (Basel) 2019;11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6409992.
5. Hanigan HM, Laishes BA. Toxicity of aflatoxin B1 in rat and mouse hepatocytes in vivo and in vitro. Toxicology 1984;30:185-193. https://pubmed.ncbi.nlm.nih.gov/6424269/.
6. Ikegwuonu FI. The neurotoxicity of aflatoxin B1 in the rat. Toxicology 1983;28:247-259. https://pubmed.ncbi.nlm.nih.gov/6138886/.
7. Wogan GN, Paglialunga S, Newberne PM. Carcinogenic effects of low dietary levels of aflatoxin B1 in rats. Food Cosmet Toxicol 1974;12:681-685. https://pubmed.ncbi.nlm.nih.gov/4375655/.
8. Martins LM, Sant’Ana AS, Iamanaka BT, et al. Kinetics of aflatoxin degradation during peanut roasting. Food Research International 2017;97:178-183. https://www.sciencedirect.com/science/article/pii/S0963996917301187.
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.