Endocrinology of Sika Deer

There have been few studies of endocrinology of sika deer in Japan, although several studies have been conducted on reproductive physiology. In recent years, we have obtained basic information on sika deer endocrinology by applying fecal steroid analysis as a noninvasive method. In this chapter we explore hormonal changes during the estrous cycle and pregnancy in female sika deer and in addition consider what is known about "silent" ovulation. For male sika deer, we provide the annual testosterone pattern and relate it to aggressive behavior.