Relationship between acorn selectivity and tannin astringency in three middle- and large-sized mammal species inhabiting the western part of the mainland, Japan

Abstract

It is well known that acorns, the seeds of Fagaceae family plants, are important food sources for many wildlife species during autumn and winter. However, they contain tannins as defensive chemicals. We conducted cafeteria tests on wild mammals using acorns of four plant species: Quercus serrata, Quercus acutissima, Quercus glauca, and Castanopsis cuspidata, all of which have different tannin astringencies. In the cafeteria tests, although the data were insufficient and fragmentary, raccoon dogs (Nyctereutes procyonoides) significantly selected the less astringent Castanopsis cuspidata over the relatively strong astringent Quercus spp. Since some rodents and browsers have been reported to have physiological responses to tannins, it is desirable to develop physiological studies in raccoon dogs and other middle- and large-sized omnivores.