Rat and Mouse
A rescued rat, by Rattie Rescue / Flickr
Rats and mice are omnivorous species. They are hind-gut fermenters, meaning fermentation of fiber occurs after the stomach and small intestine. Because of this, they practice coprophagy to consume valuable nutrients that were newly formed in the hindgut and would be lost in the feces. Most commercially available pellets provide all the nutrients a rat or mouse needs. It is better to provide hard pellets and some supplemental grains, because they beneficially wear down incisor teeth. Their diet maybe supplemented with seeds, fresh vegetables, and fruits. However, it is important to limit their intake to prevent them from preferring the treats and not consuming the pelleted diet. In addition, too many treats can cause nutritionally related diseases. It is important that food is available at all times. We have to remember that they have a very fast metabolism and the lack of food can affect them seriously in a short period of time.