Abstract
Characteristics relating to the reproductive performance of wild male Japanese marten (Martes melampus melampus) were studied in Mt. Nyugasa, Nagano prefecture through the period from September 1996 through August 1997. Annual changes in testicular size, plasma testosterone concentration, home range and active time were analyzed in wild captured male marten and using the radio-telemetry method. The total number of animals captured and plasma samples obtained during this period were 46 individuals and 36 samples, respectively. Mean size of testes of the male marten started to increase from April and showed a peak during late June to mid July. Plasma testosterone concentrations exhibited a high level during May to June and slightly decreased in July. Home range area of the male expanded markedly in July and active time was at its peak in July and August. From these results, we concluded that the mating period in the local population of marten was mainly in July.
