and Cathy Bickel
The core of your gerbils' diet should be a high-quality commercial gerbil food, a breeder-developed formula, or a home recipe from a reliable source. Gerbil food should have a minimum of 14% protein. Many commercial formulas labeled "Hamster and Gerbil Food" contain less than 14% protein. These formulas are okay for hamsters, but gerbils need heartier fare. You may find better, quite suitable foods sold as "Rat and Mouse Formula." Avoid those with many green alfalfa pellets, which gerbils will ignore. Some commercial rabbit food mixes contain antibiotics that gerbils shouldn’t have.
Choose a commercial food that has a mix of grains and seeds such as pumpkin and sunflower seeds. Formulas with a preponderance of tiny millet seeds are generally not of very high quality, although gerbils adore an occasional spring of millet spray, which you can purchase in the bird aisle. Corn is considered by some breeders to be second-rate nutrition, but some gerbils do enjoy it. Consider mixing in some regular supermarket oatmeal with your commercial food. In addition to seed mix, your gerbil will enjoy and benefit from small amounts of timothy hay, green vegetables, and fruits. Add green foods to your gerbils' diet gradually; at first, perhaps twice a week, gradually increasing to daily if you wish. Gerbils will happily eat bits and pieces of things intended for the dinner table: raw romaine lettuce, kale, beet greens, swiss chard, or spinach; cooked sweet potato or broccoli; a blueberry, strawberry, or bit of apple; even an occasional piece of cooked pasta, without sauce.
Foods to avoid: citrus fruit and peels, potatoes, chocolate, avocado, rhubarb, kidney beans, onions, shallots and apple seeds. A bit of dandelion is okay, but many other flowers are toxic to gerbils. They should not have much cheese, since lactose is hard for them to digest. The exception for cheese is when the gerbil has difficulty eating regular food due to problems with his teeth: eating a bit of cheese with his other soft food is better than going hungry. If you wouldn't eat a food raw, you probably shouldn't give it to your gerbils.
Gerbils do not need a food bowl; they will simply fill the bowl with bedding. Food can be dumped directly on the bedding so that they will find food when they dig, which is what gerbils do instinctively when they are hungry.