Gerbils need a sensible diet to make sure that they have the balanced nutrients - including protein, minerals and vitamins - to sustain their little bodies.
By reading many books one could conclude that regular feeding with any old "Rodent Mixture" from the local pet shop will fit their needs, but let us quickly sweep away that old wives tale! What is okay for mice, rats and hamsters, could, seriously harm your gerbils health in the long run.
The choice of mixture that you feed to your gerbils is vital and will go a long way in determining whether there will be major health problems later in their lives.
Young gerbils appreciate plain oats in the enclosure and adult gerbils devour these foods quickly. Budgie food is good for younger gerbils, while older ones tend to ignore the small seeds in favour of larger items, though spray millet is consumed.
In the wild gerbils do eat insects and other small living creatures, but I do not provide any form of meat for gerbils and rely upon other forms of food. Cannibalism of baby gerbils is rare and I strive to make it stay that way by avoiding the possibility of developing in our gerbils an appetite for flesh of any kind. In the decades that I have kept gerbils there have been only a few cases of cannibalism and this is a vindication of the non-meat policy.
Do not take the previous information to imply that you cannot give gerbils peanuts and sunflower seeds, but it is important to ration such items because they will be consumed to distraction. Regard peanuts and sunflower seeds as treats that will "spice" up their diet and help avoid the boredom that can creep into their daily lives, from a food point of view.
Feeding such items by hand is a good way to get the gerbil accustomed to hand contact and smooth the path to more involved handling. Avoiding too much of the fats that these items contain can thus prevent obese gerbils that always look sluggish, unattractive and of course down right unnatural.
From an early age I start my gerbils on fresh vegetables and fruit because this is a natural way to provide water and the goodies that gerbils need while growing and developing strong bones, muscles, teeth, and so on...
Cucumber is demolished in no time - which usually results in cucumber skins littering the floor of the enclosure. Apple is another favourite, along with grapes, carrot, cabbage and celery. It is best to remove such items after a day because they can dry out and start to smell otherwise.
Gerbils attack mineral blocks the moment that they are introduced into the enclosure and this applies equally to pups too. Instinctively they realise that they need the salts, minerals, seaweed, starch, calcium phosphate, talcium that the blocks contain - they may not know the fancy names, but they like the results. Always ensure that such blocks are present in the enclosure.
Finally, gerbils love toast. Many mornings I cook some toast and cut it up into little squares. I place these squares of toast into the gerbil enclosures - minus the margarine - and watch them all stand around eagerly consuming their portion. Very rarely I put some peanut butter on the toast, but this can sometimes lead to unsavoury displays of gobbling down your food and then trying to eat your partners.....
There are a variety of treats that your gerbil can have. Gerbils can be treated with chocolate drops that are especially made for pets, but these can be unhealthy if they are fed to your gerbils in excess. A healthier alternative is to give your gerbils yoghurt drops, witch can be obtained in a variety of flavours, and have added vitamins to help meet your pets requirements and keep them healthy.
Dried fruit will often be accepted readily by your gerbils. A selection of different dried fruits can be obtained form a good pet shop.
Hanging sticks can also be used. These let your gerbils treat themselves when they feel like it. These are available in flavours such as wild fruit and nut, but flavours like popcorn etc.. can also be found.
The key to treating is to keep every thing in moderation. Keep treats in small amounts, especially things like lettuce, which are mostly water and can cause diarrhea. You must still feed your gerbils their required staple diet, as this is what they live off of.