Japanese monkeys living in the Okoppe Basin of the Shimokita Peninsula: The first report of the winter follow-up survey after the aerial spraying of herbicide

Abstract

In regards to the early winter ecological survey of the Japanese monkeys living in the Okoppe Basin and to investigate the aftereffects of the herbicide which was sprayed aerially by the Aomori Regional Forestry Office, I obtained the following results: three troops were found and their nomadic ranges were 15 km², 16 km², and 18 km², respectively; the total population was about 120 head; they used to feed chiefly on the small ‘red berries’ of shrubs during this season; the ‘red berries’ have hardly been seen in and around the area where the herbicide was sprayed; the monkeys never moved around in this polluted area, which they had previously frequented every year; these ‘red berries,’ which usually remain until the middle of January, were almost entirely consumed by December, 1970, and the monkeys had already begun to eat bark and winter buds. The shortage of their main foods will inevitably exert a serious influence on their lives during the severe winter.