Objectives of the Research

 What we wish to do is to explore and propose an adequate bear management plan that will enable man and bear to continue their coexistence. This objective will be achieved through analysis and evaluation of the living mode and environment of black bears in Okutama Mountains in Tokyo.

Period of the Survey: Begun in 1992, it is ongoing.

Target Area: Our survey covers all the habitable areas of 550 square
kilometers, but a particular emphasis is put on the rims of Lake Okutama. The
items of our survey are extensive, so allow us to list up main items.

Capture

　Capturing it alive, we measure the bear's body weight, sample its tissue and/or blood, and attach a radio-wave transmitting collar

Photo: Weighing an adult male (74 kg, 11.5 years of age). The black bears  in Tokyo are considered smaller than those in Tohoku and Hokkaido.

Radio telemetry

　We track the roaming paths of the radio-attached bear and look into its life patterns.

A snapshot from radio-telemetry tracking

Photo: Locating the hibernation den of the radio-tracked bear. The directional antenna points to the bear's hideout.

Survey of food items

　Acorns serve as a principal food for bears in autumn. We examine the annual yield of acorns as well as its variation from year to year.

Photo: A seed-trap is being mounted for quantitatively estimating the number of Konara oak(Quercus serrata), Mizunara oak(Quercus crispula), Chenuts that have bore fruit. About 250 traps have been set up in the mountains at present.

A scene of scat sampling

　Analyzing the contents of bear scat allows us to guess the types of food the bears eat and how they vary over a year.

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