Ultrasonic vocalizations in rats anticipating circadian feeding schedules.

•Activity and ultrasonic vocalizations (USVs) were recorded for 2h or 24h in rats fed ad libitum or 2h per day in the light period.•Food restricted rats exhibited a daily rhythm of food anticipatory activity.•Food anticipation was accompanied by FM and flat ∼50kHz USVs.•Flat ∼50kHz USVs were more dependent on the presence of food.•An audible tone prior to mealtime modulated anticipatory locomotor activity but did not evoke ∼50kHz USVs.