Factors influencing winter home ranges and activity patterns of raccoon dogs Nyctereutes procyonoides in a high-altitude area of Japan

Abstract

Between October 2006 and June 2007, we radio-tracked six adult raccoon dogs Nyctereutes procyonoides (Gray, 1834) in a high-altitude area of Japan to determine which factors influenced home ranges, daily movements, and activity patterns of Japanese raccoon dogs, with an emphasis on the winter season. The home-range sizes for the six individuals were smaller in winter than in autumn. In winter, the daily movement distances significantly decreased in response to decreasing temperature and increasing snow depth, suggesting these environmental factors contributed to a decrease in the home-range sizes during this period. Moreover, during daytime, raccoon dogs were more active in winter than in the snow-free periods (autumn and spring), and the proportion of the daytime movement distances to the total daily movement distances significantly increased as the mean daily air temperatures decreased. Therefore, it appears that the raccoon dogs in our study area passed the winter by minimizing their energy expenditure by restricting their movements when temperatures were at their lowest and snow depth was highest, and by moving more during the daytime when temperatures were higher.