Rat Feature Distinction
The distinctive feature of the rat is its variety: instead of specializing in a particular kind of food, rats have specialized in omnivory. Accordingly they have a system of behavior which enable them not only to find food is a substantial area around their nest but also, to some extent, to select food according to need.
The explanatory behavior of rats keeps then informed on food supplies to their neighborhood; superimposed on it is additional tendency to be active when fasted or in some other deprivations, All possible food material are sampled, though some substance with (to man) strong tastes or odors are rejected. There also certain fixed preferences, for instance for sweet substances.
These preferences, seemingly independent of experience, have no evident homeostatic function; in detail they differ between wild and laboratory rats. The primary homeostatic effect of feeding is the maintenance of a steady energy intake. The selection a good deal on habit formation; foods, and avoidance of unfavorable (toxic) mixtures, both depend a good deal on habit formation; foods are sought or avoided according to their previously experienced internal effects, at least if these are fairly rapid.