著者

松浦 義雄

出版者

東京動物學會

雑誌

動物学雑誌

巻号頁・発行日

vol.54, no.12, pp.466-473, 1942

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The Northern Porpoise Whales visit the coastal waters of Sirohama, Tiba Prefecture in the months extending from June to October every year and are caught in numbers by small whale-boats in the period above-mentioned. Males and females show no significant difference in length, but on the average the females grow rather larger than the males, the fact is quite different from what is known on the most toothed whales, where the males are far greater than the females. As is known on the most whalebone whales and sperm whales, this whale also leaves a pormanent records of all ovulations in the ovaries as a form of corpus luteum. The females reach the sexual maturity at the approximate length 10.0m.