Blainville's Beaked Whale

Blainville's beaked whale, or the dense-beaked whale, is believed to be the widest-ranging Mesoplodon beaked whale. Males reach at least 4.4 m and 800 kg and females at least 4.6 m and one tonne, and calves are about 1.9 m and 60 kg at birth. It is dark bluish grey on top and lighter below, with a head that can be brownish shading to light grey around the lip and jaw. Animals may carry white oval scars, possibly from cookie-cutter sharks, and adult males also long white scratch scars (Wikipedia, general species account).

It inhabits deep offshore water at 200–1,000 m and is associated with steep underwater structures. It feeds mainly on squid and small fish by suction rather than biting, in groups averaging about four animals, and there is no evidence of seasonal migration. It stays silent for up to 80% of the time. Its occurrence in Japanese waters is documented by the National Museum of Nature and Science marine-mammal database.