Narita, R., Sugimoto, A. & Takayanagi, A. 2006: Animal components in the diet of Japanese black bears Ursus thibetanus japonicus in the Kyoto area, Japan. - Wildl. Biol. 12: 375-384.
We measured stable carbon and nitrogen isotope ratios of hair, muscle and potential food items of Japanese black bears Ursus thibetanus japonicus in Kyoto Prefecture and its surrounding area in order to determine the contributions of animal and plant foods. The ä13C values of hair samples of bears were -22.7 ± 0.4‰ in early summer, -22.8 ± 0.3‰ in late summer and -22.7 ± 0.7‰ in autumn, while ä15N values were 3.5 ± 0.4‰ in early summer, 3.2 ± 0.4‰ in late summer and 3.6 ± 0.5‰ in autumn. The ä13C values of muscle samples of bears were -24.6‰ in early summer, -23.2‰ in late summer and -23.1 ± 0.3‰ in autumn, while ä15N values of bears captured were 3.7‰ in early summer, 5.0‰ in late summer and 4.5 ± 0.7‰ in autumn. We determined the isotopic endpoints of seven food groups from the isotope ratios of food groups and calculated the contribution of each food group using a stochastic method. Our results suggested that animal components were the major constituent of body tissue, contributing > 61% in all samples except for muscle samples collected in early summer. In muscle samples collected in early summer, none of the food items were estimated to be the major source. In cases in which the animal components were estimated to be major food sources, invertebrates were estimated to account for most of the animal components. It was concluded that animal components are an important source of tissue material in Japanese black bears in Kyoto and its surrounding area.
Key words: animal foods, food habits, isotopes, Japan, Japanese black bear
Ryo Narita & Atsushi Takayanagi, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 Japan - e-mail addresses: ryoryo@kais.kyoto-u.ac.jp (Ryo Narita); atsushi@kais.kyoto-u.ac.jp (Atsushi Takayanagi)
Atsuko Sugimoto*, Center of Ecological Research, Kyoto University, Kamitanakami Hiranocho, Otsu, Shiga 520-2113, Japan - e-mail: atsukos@ees.hokudai.ac.jp
*Present address: Graduate School of Environmental Earth Science, Hokkaido University, N10, W5, Sapporo 060-0810, Japan
Corresponding author: Ryo Narita
Received 30 April 2005, accepted 20 September 2005
Associate Editor: Andrew E. Derocher