Rats are omnivoresOmnivore An animal that eats both vegetable and animal matter. (Carnivore: meat eater; herbivore: plant eater). Both the rat and the mouse are omnivores. although this is a matter of discussion. Some regard rats as herbivores that can easily adapt to omnivoreOmnivore An animal that eats both vegetable and animal matter. (Carnivore: meat eater; herbivore: plant eater). Both the rat and the mouse are omnivores. feeding habits.
Rats learn by conditioningConditioning Habit formation or learning of conditional behavioral responses. This may for example occur when food delivery is coupled with a particular sound. to associate a particular flavor with illness and other external factors. In addition, they dislike strong flavors.

CoprophagiaCoprophagia The consumption of feces by an animal directly from its own anus, often during an active phase. It meets a need for essential nutrients.

The rat engage in coprophagia. By reingesting 5–50% of its stool, the alimentary canal efficiently absorbs a large quantity of vitamins, minerals, trace elements, and other nutrients during the second passage.

In laboratories, rats are most often fed ad libitumAd libitum Latin. At one's pleasure, free. In laboratory animals context: unlimited supply of food. Antonym: Restricted.. However, restrictedRestricted Limiting/limited. In the context of laboratory animals, the term relates to diet. Antonym: Ad libitum. It can also refer to an animal’s inability to move freely. feeding can contribute to increased lifespan in these animals, partly due to a reduction in the incidence of spontaneous tumorsSpontaneous tumors Tumors that are not induced, but that occur as a result of aging or some other natural defect. The frequency and incidence of spontaneous tumors and the tumor type are both species- and strain-specific..