The oldest finless porpoise in captivity has died of old age at an aquarium in Toba, Mie Prefecture, Toba Aquarium officials said Thursday.
The porpoise, known only as No. 36, died Wednesday. He was thought to be 35 years old.
No. 36 had been kept at the aquarium since being captured in Ise Bay on Sept. 20, 1973, the officials said.
He had been on a drip since weakening about a week ago.
The previous oldest porpoise of this kind, found in waters near Kyushu, lived to be 25, the officials said.
Finless porpoises are usually between 1 meter and 1.5 meters long and live along the coasts of Japan and China and in the Indian Ocean.
Several finless porpoises are being kept in aquariums in South Korea and China, but they are much younger than the late No. 36, the officials said.