Friday, April 15, 2011

Of the Monstrous Pictures of Whales

"But it may be fancied, that from the naked skeleton of the stranded whale, accurate hints may be derived touching his true form. Not at all. For it is one of the more curious things about this Leviathan, that his skeleton gives very little idea of his general shape"

- Herman Melville. Moby-Dick; or, The Whale. Chapter 55.


Suspiciously similar to a photo taken by Markus Bühler.

What would be made of cetaceans if they were known only from fossil bones? The reconstruction above shows how a mildly unusual Sperm Whale (Physeter macrocephalus) may appear in this hypothetical alternate reality. The unfortunate cetacean is subjected to almost unadulterated 'shrink-wrapping', with the exception of the 'forehead' region. This area of the skull has a strongly concave surface which would look highly implausible on an aquatic creature. What the angle of the reconstruction fails to show is that the concavity is part of a basin-like depression which covers most of the Sperm Whale's cranium; coupled with crests for the attachment of the maxillonasalis muscle, it should be clear that vast amounts of soft tissue were present. The soft tissue is so considerable in mass that Clarke (1978) referred to the head of a Sperm Whale as "largely snout and the crest of the skull necessary to support it". 

A huge nose can be inferred from a Sperm Whale skeleton, yet Melville's assertion is still likely correct. A sloping, prow-like snout would probably be viewed as most likely due to the shape of the skull and hydrodynamic concerns. It seems unlikely, if not impossible, for internal structures such as the spermaceti organ, junk, museau de singe, and distal sac to be inferred; the first two have a major influence on external appearance, as demonstrated by Carrier et al. (2002). Who knows what functional morphology would be hypothesized without knowledge of the complex inner anatomy of the snout, but with knowledge of the strong asymmetry, lack of functional teeth, and a big lump of tissue that must be doing something other than fill out a basin-shaped skull. 


Thanks to cryptozoology, hypothetical alternate realities are not needed for cetacean remains to be grossly misinterpreted. I really couldn't ask for a better springboard for showing off the ludicrous contrast between the skeleton and life appearance in cetaceans.




Above is an extremely literal reconstruction of the 'hairy' Russian 'plesiosaur' carcass. The position of the nostrils is unambiguously cetaceous, but surely the head is too crocodilian and the body too serpentine for this to be a known species? Nah, the skeletal morphology is unambiguously identical to that of a Beluga whale (Delphinapterus leucas). Who knew that beneath all that blubber and muscle, Belugas were reptilian monsters?

Delphinapterus leucas skeleton from Wikipedia Commons.
Beluga, from Flickr user Travis S.
What I find particularly striking is how much of this cetacean's mass lies outside of the ribcage, and that the ribcage appears to have very little 'influence' on the overall shape of the animal.


Delphinapterus leucas head 3 - taken and modified from Wikipedia Commons.

It seems that a few suggestions of the underlying skull can be seen on the live Beluga's head, but it still seems amazing that the two have anything to do with one another.

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In 1996, a 'dragon' skeleton was pulled out of the ocean in Langkawi, Malaysia. The only available photo is unfortunately tiny, but the shape of the skull as well as the shape and number of the teeth make an Orca (Orcinus orca) identity probable. That, and it was identified as such.


Based on this.

The situation is essentially the same as that of the Beluga, but with a scarier and vaguely crocodilian head. I think that this shows that, underneath that adorable layer of blubber and high-contrast markings, Orcas are capable of serious macropredation.

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The Ataka carcass - Worst 'Mystery' Ever.

Something like 6-7 years back in Rhode Island, a local news station ran a brief blurb on a carcass similar in condition to the Ataka specimen being unceremoniously disposed of. It was identified as a Humpback Whale (Megaptera novaeangliae) and nobody appeared to have given it a second thought. The Ataka carcass itself is similarly a complete non-mystery - it was unambiguously identified as a Bryde's Whale shortly after washing up. Even Heuvelmans' great tome, In the Wake of the Sea-Serpents, summarily lists it as such. It is then utterly baffling that some cryptozoology sites insist that this is still a valid mystery. Apparently, some people sincerely believe that this is roaming the oceans:




A thin membrane was added between the tusks so it would have some semblance of functional morphology. Baleen whales probably have the most 'alien' looking mammalian skulls around, so it is quite difficult imagining what a blind reconstruction would look like. I'll admit I just wanted to draw something which looked like a bird skull with pincers coming out of it.


This article is a runaway introduction to a somewhat more rigorous topic - giving extinct whales proper amounts of soft tissue. Yes, shrink-wrapped cetacean reconstructions have been done in all sincerity despite, as this post hopefully demonstrated, that making no sense whatsoever.


References:

Carrier, D. R., Deban, S. M., and Otterstrom, J. (2002). The face that sank the Essex: potential function of the spermaceti organ in aggression. The Journal of Experimental Biology 205, 1755-1763. Available.

Clarke, M. R. (1978). Structure and Proportions of the Spermaceti Organ in the Sperm Whale. Journal of the Marine Biological Association of the United Kingdom 58, 1-17. Available.