A "pre-satiety sequence" in rats drinking sucrose solutions.

Food-deprived rats were given intermittent access or, in a replication, continuous access to a 20% sucrose solution. Both drinking and nondrinking behaviors were recorded. During the ensuing drinking bout, latency of lapping after snout apposition, and duration of lapping bouts, did not change. Approaches to the sipper tube usually eventuated in lapping, though aborted approaches increased in frequency late in the session. Drinking was interrupted by nondrinking behaviors which appeared in a characteristic rostro-caudal sequence: partial head withdrawal from the drinking aperture, then full head withdrawal, then movements of the front paws, then movement of the hind paws with full-body locomotion. All these behavioral changes occurred before there was any appreciable reduction in rate of lapping.