Day length affects feeding behaviour and food intake in adult male emus (Dromaius novaehollandiae)

1. In south-western Australia, male and female emus decrease their food int ake when they start breeding in early winter and increase their intake duri ng spring and summer when the breeding season and egg incubation are finish ed. 2. This annual feeding cycle seems to be under the influence of several env ironmental factors. Here, we tested the importance of photoperiod using mal e emus kept in light-controlled rooms with ad libitum access to food and wa ter. 3. Long days increased food intake whereas short days decreased it. Emus fe d only during the light hours. 4. Frequency of meals was similar under the 2-day lengths but meal duration was shorter when the emus were on short days than when they were on long d ays. Thus, day length seemed to affect appetite but not interest in food. 5. Further investigations are needed to test whether these changes in feedi ng behaviour are a direct consequence of day length or if they are secondar y to photoperiod-driven changes in sexual activity.