Beached whale skull sparks scientific interest

Remains of what could possibly be a new whale species have been found along the Skeleton Coast. Although it is still too early to tell whether this is the case, there is evidence suggesting that it could be a new species. Willem Snyman of the Namibian Broadcasting Corporation speaks to Mike Griffin, a conservation scientist in the Directorate of Scientific Services in the Ministry of Environment and Tourism (MET).

In 1998 a joint scientific expedition made up of officials from the MET and the National Museum of Namibia, amongst others, headed to Namibian shores to collectively gather plant and animal samples along the Skeleton Coast.

It was during this expedition that researchers chanced on the skeletal remains of a dead whale a few kilometres south of the mouth of the Kunene River. They found that the skull still had its lower jawbone intact, a rarity say specialists, and that there was a tooth. All the remains were submitted to the MET for analysis.

Conservation scientist Mike Griffin says he immediately recognised the skull as belonging to the beaked whale genus Mesoplodon. Beaked whales are the rarest and least-known group of the world’s whales, dolphins and porpoises, because they tend to be deep-sea mammals. They occur as solitary swimmers as well as in small groups, and are only found ashore if they wash up on the beach after dying, or happen to beach themselves when they become too stressed.

Griffin says the skull was that of an adult male whale, estimated to have been about five metres long and probably weighing several tons when it was alive. However, he says, while all the remains needed to confirm that it was a beaked whale were there, he had been unable to match them to existing records of other beaked whales.

“The lower jawbone is here, along with one tooth, so I started looking through the books. But none of the illustrations I found exactly matched this species of beaked whale. So I made measurements, took photographs and made diagrams, and sent them to the Smithsonian Institute in Washington DC, where they keep a database on the beaked whales of the world.”

His contact in Washington DC is scientist James Mead, a specialist in and curator of cetaceans (whales, dolphins and porpoises) at the Smithsonian. Mead replied that based on the evidence submitted, he thought the Namibian Mesoplodon specimen looked like M. europius, a species of the beaked whale found widely in the north Atlantic and Caribbean oceans.

Griffin says that if this were the case, the find is important because, although there are many records of beaked whales found in the southern region, there was none of the species found along the Skeleton Coast. “Now, since it does not exactly fit the look of a proper, north Atlantic, M. europius, it might be a new species altogether. Basically the shape of the lower jaw differs from that of M. europius. The placement of the one tooth is another clue. While it is in the morphological range of M. europius, it is on the very outside edge of that range, and that’s what leads me to believe that this specimen is possibly not M. europius. In general, the more people look at the genetics of whales, the more they are finding that there are northern as well as southern hemisphere whales species.”

He adds that if the whale were proven to be genetically different from its counterparts in the north, even if both the northern and the southern groups are from the same species, it might have been the remains of a new whale species that was discovered on Namibian shores. “What I’m speculating is that the specimen from the Skeleton Coast is possibly the first known specimen of a southern population of beaked whales. In other words, the Namibian specimen could be from a Southern Atlantic population of a species that could be closely related to the northern Atlantic population of European beaked whale.”

However, says Griffin , it is still too early to tell whether the skull belongs to an entirely new species of whale, since several specimens are needed to compare with each other to confidently, and scientifically, make such a statement.

“To give an example of how this works: A Mesoplodon species was washed up on a beach in Peru about 25 years ago. It was also an unknown species, and it took the scientists about 25 years to gather enough material to actually describe this new species, classified as M. peruvianus. And over these 25 years they collected a number of specimens, so they were able to bolster the statistical issue, and are now confident in describing the specimens they have as belonging to a new species.

“From where we are standing now there is one specimen from the southern Atlantic which could be a vagrant from the north Atlantic Ocean. However, it could also possibly represent a hitherto unknown population of a southern Atlantic species of Mesoplodon.”

“You might reasonably say that if, after some 50 years of opportunistic collecting of whale skulls on the Namibian coastline, this were the first one, we might wait an awful long time for the next one.”

Why not extend the search into the open ocean? Griffin explains. “It is possible – of course you could go out into the ocean and spend months and months floating around out there and you’ll undoubtedly see a couple of beaked whales as individuals, or occasionally in pairs or small groups. But although there are some beaked whales you would be able to identify, in the case of the specimen from the Skeleton Coast, you wouldn’t be able to, because the only information we have is provided by that skull.”

And although some particulars can be judged from the skull such as weight and size, says Griffin, you would also need other particulars to distinguish it accurately, such as skin colour and shape. This information is not available yet.”

There are currently about 80 species of whales in the world, of which about 40 do or should occur in Namibian waters. Among them are five species of beaked whales – possibly six…

This article appeared in the 2003/4 edition of Conservation and the Environment in Namibia.