Chapter 5: The Latest Cetology

Whales are incredibly mysterious creatures. Because they spend a lot of time under water in vast seas, observing and studying them is a real challenge. There are even species of whale whose existence has only been confirmed by the dead individuals which have washed up on beaches. Cetologists are working on various projects in an attempt to unravel whales’ mysteries and secrets.

There has been a series of announcements regarding new whale species in recent years. In 2019, Sato’s beaked whales were separated from Baird’s beaked whales and classified as a full species. The separation was based upon the fact that a group of beaked whales inhabiting the Sea of Okhotsk are different in their body size, body color, shape of skull and genes from the other Baird’s beaked whales. In the case of Bryde’s whales, the species has split into more than one full species. A group of whales with a smaller body size than Bryde’s were first described as a new species in 2003 and named “Omura’s whale”, while a group of whales which inhabit coastal waters have also been identified as a separate species and named “Rice’s whale”. Two Omura’s whales have been recorded off Chiba Prefecture, one of which is preserved as a complete skeleton. So little is known about these new species that this skeleton will surely make a large contribution to our learning about Omura’s whales.

It has been a conventional theory that there are five Japanese populations of the Narrow-ridged finless porpoise. Recent research, however, has shown the possibility of dividing the population inhabiting the seas between Sendai Bay and Tokyo Bay into two – one that inhabits the area off the Pacific coast and the other in Tokyo Bay. The Tokyo Bay population has not been well studied due to its small population size and infrequent observations. Stranded individuals, including newborns, are occasionally found on the shores in Tokyo Bay in Chiba, which suggests the porpoise may be breeding in the bay. Insignificant and slow though it may look, collecting data and thoroughly examining them will be a step forward towards unravelling the mystery of whales.

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