Specific dynamic action (SDA), the increase in metabolic rate above resting levels that accompanies the processes of digestion and assimilation of food, can form a substantial part of the daily energy budget of free‐ranging animals. We measured heart rate (f_H) and rate of oxygen consumption ( ) in 12 little penguins while they digested a meal of sardines in order to determine whether they show specific dynamic action. In contrast to some studies of other penguin species, little penguins showed a substantial SDA, the magnitude of which was proportional to the size of the meal. The energy utilized in SDA was equivalent to 13.4% of the available energy content of the fish. Furthermore, animals such as penguins that forage in a cold environment will probably expend further energy in heating their food to body temperature to facilitate efficient digestion. It is estimated that this additional energy expenditure was equivalent to 1.6%–2.3% of the available energy content of the fish, depending on the time of year and therefore the temperature of the water. Changes in f_H during digestion were qualitatively similar to those in , implying that there were no substantial circulatory adjustments during digestion and that the relationship between f_H and in penguins is unaffected by digestive state.