From March to December 2009, we investigated the behavior of captive sun bears (Helarctos malayanus) at Shanghai Zoo using manual observation and infrared cameras in order to supplement valuable information for captive management of this species. Ethograms were composed of resting, locomotion, pacing, begging, feeding, climbing, exploring, rubbing, playing, chase, sniffing, warning, fighting, mounting, cunnilingus, mating, and elimination. These behaviors were categorized as resting, locomotion, begging, stereotyped (e.g., pacing or waving), social, or other behaviors for comparison and analysis. Each animal was scanned every 6 min by one observer between 8:30 and 16:30 and by infrared camera recordings for a period of 24 hours. Observations were carried out on 5 bears (3 males and 2 females) during spring and summer, and 6 bears (4 males and 2 females) during autumn and winter. The bears ranged in age from 5 to 13 years. Sun bears spent more time resting (45.66%) in the daytime (from 8:30 to 16:30), followed by locomotion (30.01%) and begging (12.29%). Sun bears showed different patterns of activity across seasons. Locomotion(F=62.748,P<0.001)and social behavior(F=26.041,P<0.001)varied significantly among seasons. Locomotion was lower during spring and summer, and lowest in summer (13.96%). Locomotion was significantly higher during autumn and winter, and highest in autumn (43.99%). Social behavior was highest during spring and summer. Stereotyped behavior differed significantly among seasons (F=4.667, P<0.05)and was highest in spring (7.65%) and lowest in summer (0.69%). No significant differences were found in resting(F=1.857, P>0.05)and begging(F=1.180, P>0.05)among different seasons. There were significant differences in the proportions of locomotion (P=0.002) and stereotyped behavior (P=0.001) between spring and summer. Sun bears exhibited significantly higher levels of locomotion and stereotyped behavior in spring than in summer. There was no significant difference between autumn and winter in the remaining six types of behaviors. Sun bears showed different daily patterns of activities in captivity. Resting behavior exhibited a "W" type curve on a daily basis. Resting was recorded mainly from 00:00-5:00 hrs and from 20:00-24:00 hrs. Activity generally began around 6:00 hrs, and a peak in feeding was recorded at 8:00-8:54 hrs. During the same time intervals, locomotion, begging, and social behaviors gradually increased. The bears were housed in cages to which access was available from playground. In the playground, peaks of begging occurred around 10:00 and 16:00 hrs when there were many tourists in Shanghai Zoo. Activity gradually declined after 19:00 hrs as resting increased. Comparison of behaviors by age class during spring and summer indicated that age was a significant variable affecting resting, locomotion, social, begging and stereotyped behaviors. Males showed significantly more social behavior (in spring: P=0.000, in summer: P=0.002) than females. Activity levels were higher in the playground than in cages. Resting and stereotyped behaviors mainly occurred in cages, and locomotion mostly occurred in the playground. Resting behavior in cages plotted a curve of the "W" type on a daily basis. Our study showed that the behavior of sun bear is influenced by season, sex, and presence of visitors.