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LatestPhoto
A rare Andrew's Beaked Whale stranded in Western Australia. Only the males of this species have teeth which are believed to be responsible for the heavy scaring found on the bodies of many beaked whales.
Photo: Courtesy of Doug Coughran, CALM

April 24, 2002
Andrew's Beaked Whales
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Log Transcript

This is Genevieve Johnson speaking to you from the Odyssey in Fremantle, Western Australia.

Although some people may find it difficult to believe, scientists still know almost nothing about several species of large whales. This mysterious group of roughly twenty species is the beaked whales. (Perhaps even more surprising, is that there may be more beaked whale and baleen whale species yet to be discovered.)

Over the course of the Voyage so far, we have spoken several times about beaked whale sightings and strandings. Some were encounters with relatively well-known species, while others were species so unfamiliar we couldn't identify them at sea. A few days ago, Doug Coughran of Conservation and Land Management (CALM) in Western Australia informed us of another beaked whale stranding.

Every stranding of such a little-known group of species may provide precious clues and shed new light on the otherwise all-but-impenetrable lives of these animals. As a group, beaked whales are the least known of all marine mammals and there are still several species for which there are no confirmed sightings at sea, only corpses and skeletons. As we move across the oceans of the world, it is our hope and intention to contribute to the slowly expanding knowledge about this group.

Although many beaked whales are large animals, people seldom seem to notice them, and it is often only through strandings that we learn anything at all about them. Given how little one can learn from a partly decomposed corpse it is not surprising that our knowledge about many beaked whale species is all but non-existent. This most recent, local, live-standing was of the very rare Andrew's Beaked whale-found, alive, by a group of recreational campers on remote Yeagarup Beach, south of Point Naturaliste. Attempts were made to return the 4 meter male to the sea, but unfortunately as with most beaked whale strandings, the animal eventually died. No one had any tools with which to perform a necropsy. However, we did get skin samples for DNA analysis, and blubber samples for toxicology studies. Those running the stranding then buried the carcass so decay organisms could strip the flesh from its bones. When that process is complete, in about a year's time, the Albany Whaling Museum will recover the skeleton and display it as part of their public education program.

Andrew's beaked whales are only known from about 20 stranded specimens, all of which have come from southern Australia, Tasmania and New Zealand. Such a small number of specimens makes it impossible to get a clear idea of the overall distribution of this species. In fact, this is just the third record of Andrew's Beaked Whale from Western Australia. The last occurred in 1961 (more than 40 years ago).

Beaked whales are big animals, and upon seeing one stranded, most bystanders have no idea what it is. They often ask whether it's a giant dolphin. Like sperm whales, beaked whales have teeth rather than baleen. However, evolutionarily speaking, sperm whales appear to be more closely related to baleen whales than to beaked whales.

One of the most surprising features of beaked whales is their teeth. Only one species, Shepherd's beaked whale, has what you might think of as a standard set of teeth-uniform rows in both upper and lower jaws. In the other 20 odd beaked whale species the females rarely have any teeth, and the males are distinguished by either 2 or 4 teeth in one of several peculiar arrangements. For example, in some species a single pair of huge teeth, that are greatly compressed side-to-side, erupt from the lower jaw. In some instances they eventually overgrow the upper jaw so that the whale can barely open its mouth. When a whale's teeth reach this stage, no one knows how it feeds, but it does; whales have been found that have reached this point, but that show no signs of starvation.

LatestPhoto
The extensive scars on the body of the Andrew's Beaked Whale.
Photo: Courtesy of Doug Coughran, CALM

The males of many species are frequently marked with scars consisting of parallel pairs of lines in "criss-cross" patterns covering the animals' bodies. It is believed that the teeth of other males are responsible for this scarring, and that it occurs during skirmishes between males.

Such scars were particularly evident on the dark, blue-black body of the Andrew's beaked. It was a mature male, so we had the rare chance to observe the pair of fully erupted, wide, flat teeth located in raised sockets on the highly arched jawline, halfway along the length of the lower jaw.

Presumably such teeth serve some function in securing a mate; they are probably either used as visual threats by one male to another, or as weapons for fighting (or as a feature useful to females when assessing the desirability of different males as potential mates). However, as with almost everything we know about these animals, we're just guessing about the true use of the bizarre teeth of beaked whales.

Links - Beaked Whales

Log by Roger Payne & Genevieve Johnson

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