Effects of body size on the diurnal activity budgets of African browsing ruminants.

摘要: We compared the diurnal activity budgets of four syntopic species African browsing ruminant that differ widely in body size. These were concurrently studied through all phases seasonal cycle, same area, using methods. tested five predictions from literature on how size is expected to influence behaviour tropical ungulates: smallest members guild exhibit (1) lowest allocation time activity; (2) greatest hour-to-hour variation and resting time; (3) reduction during hottest days; (4) least change between wet dry seasons ratio feeding: ruminating (5) budget vigilance. Prediction 1 was supported smaller spent less being active day. 2 also more variable their relative allocations successive hours Contrary 3, however, with increasing temperature found for largest member. The can achieve daily food intake requirements by feeding at night cool day, while larger have feed day are thus susceptible thermoregulatory constraints foraging. 4 partially upheld (giraffe) displayed widest cycle. 5 not supported, indicating multiple factors interact determining vigilance behaviour.