Circulating inhibin and testosterone during sexual maturation and reproductive seasonality of captive male killer whales (Orcinus orca)

The present study aimed to investigate the reproductive biology of male killer whales. Changes in the concentrations of two circulating testicular hormones, inhibin and testosterone, were monitored during sexual maturation of two male Type 1 Eastern Northern Atlantic killer whales over a period of 20 years. The two killer whales grew rapidly at the pubertal stage and reached a plateau at the age of 23 and 20 years, respectively, after which growth slowed down. In the younger male, circulating inhibin was higher in the juvenile than in the pubertal and mature stages; whereas circulating testosterone exhibited the opposite trend. The pubertal period was estimated to last approximately 5 years, from 12 to 17 years of age. In the elder male, circulating testosterone was high from the onset of this study (12 years of age), when the animal also sired successfully for the first time. This finding shows that the male killer whale is possible to sire even if it is not socially matured, if there is opportunity for copulation. During the mature stage, both animals exhibited significantly higher circulating testosterone concentrations in spring compared to autumn and winter; whereas no seasonal change was observed for circulating inhibin. These results clearly demonstrate that the male killer whale is a seasonal breeder, even though it is fertile throughout the year. This is the first study to elucidate the inhibin concentration and secretory source in the male killer whale

Hiroshi Ichikawa, Yudaya-kyo no Seishin Kozo (The Spirit of Law in Rabbinic Judaism) (University of Tokyo Press, 2004)

Book ReviewThis book review was originally written in Japanese

Abraham the iconoclast : different interpretations in the literature of the second temple period, the texts of rabbinic Judaism, and the Quran

ArticleThe Hebrew Bible does not describe how Abraham, the common patriarch of the three monotheistic faiths, came to know the one God. However, literature from the Second Temple period, texts of Rabbinic Judaism, targumim (Aramaic translations of the Hebrew Bible), the Quran, and other documents abound with narratives based on a common plot that recount how Abraham came to know the one God, confronted the idolatry that had continued until the generation of his father, and broke down the practice through various schemes. This paper presents translations of passages taken from the Book of Jubilees, the Apocalypse of Abraham, Genesis Rabba, Targum Pseudo-Jonathan, and the Quran that relate the tradition of “Abraham the iconoclast, believed to have been highly popular at the time of the writing of the respective texts. The passages are then analyzed to extract a common plot, identify different focal points, and compare in terms of Abraham\u27s relationship with his father, Terah. From this comparative reading, the following observations can be made: the focus is placed on the importance of knowing one God in the Book of Jubilees, and on confrontation with idolatry in the Apocalypse of Abraham; various narrative components appear evenly with similar frequency in Genesis Rabba and Targum Pseudo-Jonathan, possibly to maintain conformity as exegeses; in the Quran, the focus is on Abraham\u27s role of introducing the monotheistic notion to local residents