Explaination of the cover photograph
Circulating Testosterone and Inhibin Levels at Different Ages in the Male Beluga
(Delphinapterus leucas)
Etsuko KATSUMATA et al. (pp. 293–300)

The beluga is a medium sized toothed whale in the family Monodontidae and lives around the Arctic Ocean. Body length of matured beluga is 300–500 cm and, the body weight is 500–1,500 kg which altered by groups. “Duke” in this picture is a quite large beluga (length 480 cm, weight 1,500 kg) and still in Kamogawa Sea World. In our study, circulating testosterone and inhibin levels of two captive belugas were measured for 9 years in order to monitor gonadal function during the course of sexual maturity.

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