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1 September 2017 Three Cases of Anomalously White Risso's Dolphins Grampus griseus in Japan
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Three male anomalously white Risso's dolphins Grampus griseus were observed in the waters off Taiji, Wakayama, Japan. One (GG-1) was captured alive in 2007, and the other two (GG-2 and GG-3) were captured in 2014. The color pattern of GG-1 is approximately divided into two parts; the middle of the trunk and the lower part of the dorsal fin are white, whereas the anterior and caudal portions have dark pigmentations. GG-2 has an almost white body with some dark pigmentation in the head region, and GG-3 has a completely white body with some sparse dark flecks around the throat. All three dolphins have dark eyes similar to a normally pigmented Risso's dolphin; however, the oral mucosa of GG-2 and GG-3 and the mucosa in the blowhole of GG-3 are white to pinkish in color without any dark pigmentation. Furthermore, the mucosa in the blowhole of GG-2 is a mixture of white patches and dark pigmentation. These three dolphins are the first anomalously white Risso's dolphins to be kept in captivity; therefore they are valuable for understanding the cause of body color variations and the anomalous coloration effects in animals.

© The Mammal Society of Japan
Noriko Funasaka, Tetsuo Kirihata, Masayuki Hosono, Hidehiro Kato, and Seiji Ohsumi "Three Cases of Anomalously White Risso's Dolphins Grampus griseus in Japan," Mammal Study 42(3), 173-178, (1 September 2017).
Received: 23 March 2017; Accepted: 1 June 2017; Published: 1 September 2017

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