Rodent (Rat and Mice) Feeding Guide

Rat and mice are omnivores, eating both plant and animal based foods. Historically, they have been fed muesli, grain and seed mix diets. This allows the rodents to pick out of the mix and is generally not recommended due to the lack of nutrition and high fat content in this diet. This can lead to many health deficiencies, organ disease, and obesity, so it is best avoided.

Instead, a rodent ration providing minimum 16% protein and 4-6% fat in either a pellet or block form is recommended, limiting to 1 teaspoon a day (for rats). These should not contain any nuts, dried fruits or coloured pellets, and should comprise 80-90% of their total diet. Vegetables should be provided daily (ad lib), but the other foods should be portion controlled as rats with unlimited food supply have been shown to be obese, with higher incidences of mammary, pituitary and pancreatic cancers. Keep in mind, a finger nail sized portion for rats and mice, is equivalent to a plate sized portion for a human. A calorie restricted high quality diet is one of the best ways to prevent disease.

Fresh washed nutrient dense fruits like berries, bananas, apricot and pears may also be supplemented into the diet in moderation. 

  • Vegetables: broccoli, bok choy, capsicum, corn, zucchini, cucumber, corn, herbs, peas, carrots
  • Fruits: apple, banana, citrus, melons, pears

Acceptable foods as occasional treats (in small and limited amounts to avoid obesity) include:

  • Carbohydrate: whole meal (brown) rice, whole meal pasta, oats
  • Dairy: low fat yogurt and cheese (in tiny amounts as cheese can be high in fat and rats cannot tolerate high amounts of lactose)
  • Meats and nuts: red meat, chicken, fish, unsalted raw nuts. Careful with meats as the high protein has been associated with the development of kidney disease in adult rats.
  • Non meat sources of protein include beans and lentils such as chickpeas, butter beans, kidney beans
  • Plain popcorn
  • Low sugar cereals like cheerios
  • Commercially available seed based diets

Avoid high fat and sugar foods such as fast foods and sweets.

Foods that are TOXIC include: Avocado, garlic, onion, coffee, tea, and alcohol.

Fresh water should be available daily, whether in a bottle sipper or bowl, it should be emptied, cleaned and refilled daily. Sipper bottles are preferred to prevent bedding material soiling the water in a bowl, however, they can become blocked or leak, so it needs to be changed and tested daily. Take caution with new pets as they may not recognize water placed in a different type of container and can dehydrate quickly if not drinking.

On average, rats consume about 5-6grams of food per 100gram body weight, and drink 10-12ml of water per 100gram body weight a day. E.g. A 300gram rat will eat 18 grams of food and drink around 36ml of water a day.

Author: Dr Melanie Ngo