The temporal character of feeding behaviour in captive tammar wallabies (Macropus eugenii Desmarest)

Abstract

Four tammar wallabies, maintained in a fixed 12 : 12 light : dark cycle, were fed ad libitum, one of three foods, of differing nutrient density and fibre content, consecutively, each for a period of two weeks. During the second week, food consumption was assessed daily and the temporal feeding pattern was monitored by visible and infrared video recording. Apart from a short rest period around noon, feeding continued throughout the 24-hour cycle, peaking crepuscularly. Total daily feeding time corrected to metabolic body weight was significantly longer, but dry-matter intake corrected to metabolic body weight was significantly lower than that of larger macropod species, indicating greater investment in chewing. Feed-event duration, inter-feed-event interval, rate of feeding, and dry matter intake all increased significantly on pelleted foods of low nutritional density. Rate of feeding and feed-event duration increased significantly on diced carrot such that dry-matter intake was not significantly different to that on high-quality pelleted food. Survivorship curves of inter-feed-event intervals were predominantly linear. This and the consistently higher positive correlations between the duration of individual feed events and inter-feed-event intervals than between meals and inter-meal intervals, indicated a nibbling rather than a meal-based feeding strategy. Levels of correlation of feed-event duration with inter-feed-event interval were generally low but there was a significant increase in positive correlation when food of lower quality was given. The duration of successive feed events tended to increase on low-quality and decrease on high-quality food more consistently than did successive inter-feed-event intervals.