Behavioural ecology of sloth bear in Panna National Park, Central India.

Abstract

The patterns in daily and seasonal activity of sloth bears in Panna NP were studied and the factors that influenced the patterns were assessed. • Activity states were recorded by manually monitoring radio-tagged, motion-sensor fitted bears, and by deploying automated receiver-recording units that logged the strengths and pulse rates of signals from the bears. Daily and seasonal changes in temperature, relative humidity and other heat indices of the microhabitats used by bears were recorded using temperature and RH loggers. Tiger and human activities were also monitored to assess the influence of these on bear activity patterns. • Bears were found to be essentially nocturnal and crepuscular in activity and they rested during midday. This pattern of activity was similar among all radio collared bears, but with some variability. The differences in diel activity patterns among climatic and fruiting seasons were rather small. In the wet and cold seasons, bears extended their activity into the day hours and reduced their activity in post-midnight, pre-morning hours, as compared to the dry season. • Bears (except the cubbing females) were active almost every day of the year, and for several hours (> 10 hours) each day. Overall, bears were active for 48% to 54% of the whole day (out of 24 h) in all seasons. There were no large differences seen among months in percent of whole day, day time, night time, and morning time the bears were active, but evening time showed large differences. • The differences in activity start and end times among individual bears within seasons were large in certain seasons, and the differences among seasons of a bear were large for certain bears. Bears such as F63, F78 and M69 did not show much difference among seasons, while others such as F76, F80 and M50 showed large differences. Also many bears showed higher variability in cold and wet seasons than in dry season, particularly in activity start times. • Bears started their activity later and ended it earlier in the dry season than the other two climatic seasons. The earliest activity start and latest activity end was in the cold season. The differences among climatic seasons in both timings were statistically significant (ANOVA, α = 0.05). However, when activity start and end times were adjusted for seasonal sunset and sunrise times, the patterns in seasonal differences changed remarkably. 109 Wet season activity start times with reference to sunset were much earlier than the other two seasons, whereas the difference between cold and dry seasons became small. Differences in activity end times after sunrise between cold and the other two seasons too became small. • Escarpment habitat was most frequently used (50% to 85%) for day resting by bears in all months, followed by Lantana shrub thickets (15% to 50%). The use of escarpment was predominant in dry season months and decreased in monsoon and post-monsoon months, with a converse increase in the use of Lantana habitat as day-bed. • The core bears, which had substantial escarpment habitat available within their home ranges, used escarpments for day-resting predominantly in all seasons, and the peripheral bears, which had low escarpment and high Lantana cover available, used these habitats for day-resting variably. Tigers were generally nocturnal and crepuscular in activity during the dry and cold seasons. The activity of tigers peaked during crepuscular times; they predominantly rested during mid-day, and had a reduced level of activity during post-midnight, pre-morning hours. • Diel activity patterns of bears and tigers were similar to a large extent, in the two seasons tigers were monitored. The activity peaks of both species more or less coincided in the mornings and evenings, and high levels of activity of both occurred in night and crepuscular times. • Tiger activity does not seem to influence bear activity timings. The hourly activities of both were strongly positively correlated, even after controlling for temperature, with which bear activity was strongly correlated. • Humans using the forest habitats showed a high level of activity in the morning and evening times, moderate level of activity in the mid-day, early morning and late-evenings, and a low level of activity in the immediate premorning and early night hours. • Human activity overlapped highly with that of bear activity during early morning and evening hours. Overlap period was longer and the activity peaks of both coincided in the evenings of wet and cold seasons. No relationship could be seen between their hourly activities