Log Transcript

This is Genevieve Johnson speaking to you from the Odyssey in the central Indian Ocean.

A global expedition like the Voyage of the Odyssey affords the potential of experiencing unique events, including new information that may assist in creating a greater understanding of the marine environment and even the possibility discovering a new species.

We are anchored off a tiny islet, one of a small group that makes up the island of Salomon, an exquisitely beautiful atoll in the Chagos Archipelago. We are here because Captain John Cole of the British Indian Ocean Territory (BIOT) Fisheries vessel, the 'Pacific Marlin', informed us that there was an unidentified whale skull on Takamaka Island that we should take a look at.

We located the skull yesterday morning. It certainly did not belong to any species of baleen whale, nor was it a sperm whale or any small species of Odontocete (toothed whale) such as a dolphin. But the size and shape of the skull, and the single pair of tooth sockets situated at the tip of the mandible (lower jaw), indicatecd that the bones belonged to some species of Beaked whale.

In general, beaked whales are relatively large in size, and very poorly known. Many species are known only, or primarily, from skeletal material, or a few stranded carcasses. As both the behavior and the external appearance of many beaked whale species are poorly documented, it is very difficult, and sometimes impossible, to identify whales from this group down to genus and species, from sightings at sea. Even when specimens are found, museum preparation is often necessary for a positive identification. However, adult males of some species are an exception to this rule and can be more easily recognized by beak length, the shape of the gape, and, in particular, the location, size and shape of their teeth (though in many beaked whale species it is only the males that possess specialized teeth).

The skull we examined was originally found on the northern sandy spit of Takamaka island at the entrance to the lagoon. Diane Holmes, a yatchsperson visiting the island, discovered it over a year ago. It has been admired by visiting yachting crews passing through the area ever since. It is not known if the animal stranded alive, or washed ashore dead.

We could only identify the skull as belonging to one of three possible species. It seemed most likely that this specimen was an adult male Cuvier's (Ziphius cavirostris), or a True's (Mesoplodon mirus) or a Longman's (Mesoplodon Pacificus) Beaked whale. Cuvier's beaked whale is believed to be widely distributed in deep offshore waters of all the world's oceans. In fact it is thought to be the most widely distributed of any beaked whale species. True's beaked whale is known only from strandings and there is almost no information available regarding the natural history of this species. Longman's beaked whale is the least known of all the world's marine mammals. There is nothing known of it's external appearance, in fact the only evidence of its existence comes from two damaged skulls found in East Africa and Northern Australia.

A Cuvier's Beaked Whale Skull. Adult males may grow up to 23 feet in length.

Photo: Chris Johnson

Chris Johnson photographed the remains of the whale from all angles, and we made measurements of various parts of the skull and emailed all pertinent information to Dr. James Mead, curator of marine mammals at the Smithsonian National Museum of Natural History in Washington, D.C. for identification.

I suppose it is fair to say that we all hoped the skull belonged to that most mysterious of all whales, Longman's beaked whale. However this was not to be. We got word back this morning from Dr. Mead that the skull was that of a Cuvier's beaked whale. He said he was very pleased to have the record as not many Cuvier's Beaked Whale skulls have been found in such good condition in the Indian Ocean region. The extraction of DNA from the one tooth that was still present will also help researchers learn more about this elusive species.

The Odyssey crew has since been granted permission to collect the specimen and hand it over to the appropriate BIOT authorities in Diego Garcia. The skull will be sent to one of the major museums in the United Kingdom - the Natural History Museum or the British Museum where it will be formally identified and then possibly put on public display.

This has been an exciting find for the crew of the Odyssey. So little is known about these animals, that any finding is precious and adds to the severely limited knowledge base that has so far been accumulated about the natural history and distribution of the least well known of all the world's whales, the mysterious beaked whales.

Log by Genevieve Johnson

The crew of the Odyssey would like to thank Dr. James Mead, curator of marine mammals at the Smithsonian National Museum of Natural History in Washington, D.C. for the identification of the Cuvier's Beaked Whale skull.

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