Diel and monthly activity pattern of brown bears and sika deer in the Shiretoko Peninsula, Hokkaido, Japan

Abstract

Mammals exhibit several types of diel activity pattern, including nocturnal, diurnal, crepuscular, and cathemeral. These patterns vary inter-and intra-specifically and are affected by environmental factors, individual status, and interactions with other individuals or species. Determining the factors that shape diel activity patterns is challenging but essential for understanding the behavioral ecology of animal species, and for wildlife conservation and management. Using camera-trap surveys, we investigated the species distributions and activity patterns of terrestrial mammals on the Shiretoko Peninsula, Hokkaido, Japan, with particular focus on brown bears and sika deer. From June to October 2019, a total of 7,530 observations were recorded by 65 camera-traps for eight species, including two alien species. The diel activity pattern of brown bears was diurnal/crepuscular, similar to that of bears in North America, but different from European populations. Bear observations were more frequent during the autumnal hyperphagia period, and adult females and sub-adults were more diurnal than adult males. In addition, bears inside the protected area were more diurnal than those outside it. These findings suggest that appetite motivation, competitive interactions between conspecifics, and human activities potentially affect bear activity patterns. Similar to other sika deer populations and other deer species, the diel activity patterns of sika deer were crepuscular. Deer showed less variation in activity patterns among months and sex-age classes, while adult males were observed more frequently during the autumn copulation period, suggesting that reproductive motivation affects their activity patterns.

Estimation of breeding population size using DNA‐based pedigree reconstruction in brown bears

“…In late summer to autumn, scat samples collected in the Rusha area along the coastline contained large amounts of pine nuts (August), salmon (August–October), and acorns ( Q. crispula ; September–October), suggesting that the bears frequently travel between subalpine or forest areas and coastal areas. Furthermore, the number of bears recorded by automatic cameras installed at tree‐rub traps doubled in September–October in comparison with June–July, suggesting that bears aggregate in the coastal area in the salmon running season (Kawamura et al, 2022). Therefore, it is reasonable to suggest that few bears remained in the area with low sampling intensity all year round (i.e., highly elevated mountain areas), and that most of the bears on the peninsula had the potential to be sampled.…”