关键词: 东黑冠长臂猿, 日食性变化, 活动节律, 行为适应, 喀斯特森林

Abstract: Diet and activity rhythms are important aspects of animal behavior. Studying these topics provides valuable insights into how variations of food,temperature and illumination time impact animal behavior and behavioral adaptations. To better understand how these variables affect the endangered cao vit gibbon,we collected behavioral and dietary data using instantaneous scan sampling at 5 -min intervals on two groups in Bangliang Nature Reserve in Guangxi,China from January 2009 to December 2009. Both activity and diet showed an obvious rhythm in rainy and dry seasons. Gibbons sang only before 12:00 in both rainy and dry seasons,but later in dry season. There were two feeding peaks each day,one in the early morning after leaving sleeping trees and the other in the afternoon before entering sleeping trees. Gibbons fed primarily on fruit and figs in the early morning (07:00),and ate more fruit but less figs in the late afternoon (16:00). They consumed more leaves and buds between 13:00 and 15:00. Gibbons spent more time resting and exhibiting social behaviors between 10:00 and 12:00. Seasonality in diet corresponded with availability of preferred foods. In the warm rainy season when fruit and figs were most abundant,gibbons’diet consisted mainly of fruit and figs,as well as more invertebrates.In the cold dry season,their diet mainly comprised leaves and buds. In response to variations of temperature and lower fruit abundance in the dry season,the gibbons spent more time feeding,and decreased their time spent traveling,but increased their resting time,presumably as a mechanism to conserve energy and cope with lower temperatures. In the rainy season, gibbons spent more time exhibiting social behavior,which peaked between 08:00 and 10:00,whereas in the dry season social behavior was predominantly observed between 11:00 and 14:00.There was no obvious resting behavior peak in the rainy season,whereas resting behavior clearly peaked at 10:00 in dry season We suggest the contrasting behavior of gibbons between wet and dry seasons demonstrates the special adaptation this species has to persist in highly seasonal karst forests.

Key words: Activity rhythm, Behavioral adaptation, Cao vit gibbon, Diurnal variation in diet, Karst forest