You are currently browsing the tag archive for the ‘cephalopod’ tag.

The colossal octopus (Pierre Dénys de Montfort, 1801, pen and wash drawing)

The colossal octopus (Pierre Dénys de Montfort, 1801, pen and wash drawing)

The kraken is a giant sea monster from Norwegian and Icelandic lore. Various sailors who wrote epics from the golden age of northern exploration along the coasts of Iceland and Greenland described vast beings, larger than whales. The Örvar-Odds saga from the 13th century describes a being so large that it could be mistaken for a land mass. Its jaws looked like headlands and its teeth like rocks, yet it was capable of submerging and rising. The monster was dangerous for causing great whirlpools which could swallow ships.

Such bizarre sightings might be attributable to the vagaries of weather (or the treacherous volcanic nature of Iceland—where lands do indeed rise and sink), yet sometimes whales would be seen fighting with giant arms. Indeed occasionally 269503these arms would wash ashore. Living in a dangerous and superstitious profession, sailors kept the stories of a huge boat-sinking monster alive.

Carl Linnaeus, the father of modern taxonomy and biological classification, took these sailor’s tales seriously enough to classify the kraken as a cephalopod in his first edition of Systema Naturae (published in 1735), however subsequent editions omitted the animal. Various eighteenth and nineteenth century armchair natural scientists kept stories of the animal alive, until modern marine biologists untangled the myth from the (even stranger) realities of the giant squid and the colossal squid.

Today the kraken has moved definitively into the realm of unicorns, leprechauns, quilins, and other mythical creatures, but its popularity has not been affected. The huge squid monster haunts pirate movies and fantasy oceans all while selling rum and fending off the latest Hollywood heroes in CG animation. In fact the beast has even scaled the pinnacles of literary fame. The Kraken by Lord Alfred Tennyson is an irregular sonnet which describes the benthic monster in language which a poetic merger of Victorian gardening and Lovecraft horror. The monster sleeps in the depths of the ocean awaiting the day of revelation! Here is the poem in its entirety:

Below the thunders of the upper deep;
Far, far beneath in the abysmal sea,
His antient, dreamless, uninvaded sleep
The Kraken sleepeth: faintest sunlights flee
About his shadowy sides: above him swell
Huge sponges of millennial growth and height;
And far away into the sickly light,
From many a wondrous grot and secret cell
Unnumber’d and enormous polypi
Winnow with giant arms the slumbering green.
There hath he lain for ages and will lie
Battening upon huge seaworms in his sleep,
Until the latter fire shall heat the deep;
Then once by man and angels to be seen,
In roaring he shall rise and on the surface die.

A few weeks ago Ferrebeekeeper featured a post about belemnites, extinct cephalopods from the Mesozoic which teemed in immense schools through the reptile-haunted oceans of that bygone era.  Yet belemnites were certainly not the only cephalopods which swam in the Mesozoic seas.  Numerous shelled cephalopods—the ammonites—were widespread in every sort of marine habitat.  Ammonites are personal favorites of mine so I am not going to write a comprehensive explanation/description of the subclass.  Instead I wish to provide you with an idea of how big ammonites could get by providing a few pictures of large ammonite fossils which have been discovered.   Imagine these monsters jetting through the water with huge tentacles and big intelligent eyes scanning for giant predatory reptiles and you will have a better idea of the Mesozoic Oceans!

This one is only .7 meters (two feet) in Diameter but it sure is pretty.

Pfeffer’s Flamboyant Cuttlefish, Metasepia pfeffer (photo by Paz Santos)

In the waters of the Indo-Pacific swims an animal so profoundly fancy that it is difficult to find enough adjectives to summarize it—filigree, frilly, extravagant, surreal, frond-coated, Liberacci-esque?  Perhaps the name says it best: Pfeffer’s flamboyant cuttlefish (Metasepia pfeffer) is an adorable 2- 4 inch cuttlefish which lives in the tropical waters around Australia, New Guinea, Indonesia, and Vietnam.  Like leafy sea dragons, scorpionfish, and mighty wobbegongs, the little cuttlefish is a consummate master of disguise.  Unlike those other camouflaged sea creatures, Pfeffer’s flamboyant cuttlefish is capable of changing color and shape.  It is also capable of many different means of locomotion: it can walk along the sea floor on its tentacles, hover in the water using the fringe-like fin around its mantle, or it can zip through the sea via jet propulsion.

Pfeffer’s flamboyant cuttlefish hunts shrimp and tiny fish in the shallow sand and mud coasts of its habitat.  It utilizes complicated camouflage to hunt, but when roused it becomes a scintillating hot-mess of flashing red, white, magenta, yellow, and black in order to warn predators about its real self-defense. It turns out the list of endearing adjectives above is missing a few critical words: deadly, lethal, and poisonous. The flesh of these little cuttlefish contains a toxin as fatal to other animals as that of its famous neighbor, the blue-ringed octopus, a tiny but potent poisonous cephalopod of the Indo-Pacific responsible for many swimmer fatalities.

Pfeffer’s flamboyant cuttlefish is therefore as deadly as it is adorable, a combination which ought to make it a mainstay of action movies.  Speaking of movies you should click the following link to watch an amazing Youtube movie of Pfeffer’s Flamboyant Cuttlefish.  The happy little mollusk ambles along the ocean floor to jaunty music before zapping a shrimp with its horrifyingly alien feeding tentacles.  You should watch this all of the way: it is not a film to be missed.

Thus having successfully combined flamboyance, film, and horror, I am off to Tinseltown! I will try to blog from LA but I promise nothing.  Baby, let’s do lunch!

Vampyroteuthis infernalis (from

As you probably know, the financial firm Goldman Sachs has been famously compared to a mollusk.  During the bleakest depths of the great recession (assuming we are finally past such troubles) Matt Taibbi of Rolling Stone wrote, “The world’s most powerful investment bank is a great vampire squid wrapped around the face of humanity, relentlessly jamming its blood funnel into anything that smells like money.”  Naturally, the unbelievably rich bankers were offended and the aggrieved and bombastic spokesman for the bank Lucas Van Praag, hilariously missed the point of the insult by correctly pointing out that vampire squid are actually very small and harmless to humans.  Since then, the vampire squid has become the de facto mascot of Goldman Sachs and now represents the bank in political cartoons the same way Uncle Sam appears as the United States or a dragon represents China. The Goldman Sachs squid is usually portrayed as a giant squid dressed up in gothic garb and sporting a vampire’s voracious mien.

Gothic Squid: the reason nobody had a good job for the last three years?

Goldman Sachs indeed deserves such opprobrium for crafting shell-game style derivatives and credit default swaps which helped bring about the recession (while making the bank richer) but what did the actual vampire squid do? The real victim of the quotation was this fascinating oddity of a cephalopod which shares similarities between squids and octopuses and thus merits placement in its own unique taxonomic order, the Vampyromorphida. As Van Praag observed, vampire squid are indeed quite small: they seldom exceed 6 inches (15 cm) with another 6 inches for their tentacles.  Although they have eight arms, like octopuses, the creatures additionally possess unique retractile sensory filaments and immense blue-red eyes to help them apprehend their black surroundings. They have two light-sensitive photo-receptors on their head and their bodies are covered with photophores, specialized organs capable of producing light.  The photophores at the tips of the arms are larger than the rest and appear as white spots. Vampire squid use these photophores to communicate, to dazzle predators, to hypnotize prey, and to hide themselves by mimicking ambient surface light.

An illustration of the vampire squid by Citron

Vampire squid live in the benthic depths of the ocean 2,000-3,000 feet (600-900 meters) below sea level. They “fly” through their habitat by means of ear-like fins which project from their mantle. To deal with the inhospitable conditions of such depths, they have large gills and hemocyanin-rich blue blood.  Much like ground-water dwelling catfish mentioned in a previous post, their velvety/slimy skin is oxygen permeable in order to exploit the precious oxygen to the maximum extent.  To quote Wikipedia “The animals have weak musculature but maintain agility and buoyancy with little effort thanks to sophisticated statocysts (balancing organs akin to a human’s inner ear) and ammonium-rich gelatinous tissues closely matching the density of the surrounding seawater.”

Ballooning defensive behavior (photo by R. Flood)

Unlike most cephalopods, Vampire Squid lack ink sacs (which would be of little use in the nearly lightless depths).  To make up for the loss, they possess sacs of brightly bioluminescent mucous which they squirt out at predators to dazzle and confuse them.  Such a defense costs the squid dear and is only undertaken as a measure of last resort.  Additionally when confronted by predators, the vampire squid can inflate its webbing to appear bigger (as in the photo above). The squid pray on larval fish, copepods, prawns, cnidarians, and other deep sea arthropods.  They are eaten by deep sea fish and by deep diving marine mammals like whales, seals, and sea lions. Little is known of their reproductive cycle although young squid pass through various stages of morphologic form possessing first one set of fins, then two sets of fins, and then one again.

Common cuttlefish - Sepia officinalis (photo by David Nicholson)

When I was a child, my family went to the invertebrate house in Washington, DC.  Upon entering the building, there was a very beautiful aquarium which contained the most alien creature I have ever encountered.  It was a beautiful glistening red…and then it instantly changed color to bright white with pale dun spots.  Next the strange being sank through the water column and changed color and texture. Its smooth skin knotted up into ropey bumps.  The speckled white tuned to wavy deep brown lines.  Intelligent eyes with W-shaped pupils regarded me from what suddenly seemed to be a hunk of rock. I had encountered my first live cuttlefish.  In fact there were two in the tank, as I discovered when a patch of unremarkable sand changed shape and color and jetted to the surface while flashing rainbow colors.  They were worked up because they were about to be fed and, when eating their suppers, the cuttlefish put on a particularly good show.  They changed color like digital screens and waved their eight arms about and then ZAP!  elongated feeding tentacles shot out from under their mantles to grab the anchovies from across the length of the tank. Then they rocketed around with uncanny torpedo speed.

Cuttlefish by Doug Deep

Cuttlefish are cephalopods like octopuses, argonauts, squid, and nautiluses.  Across the long ages they have descended from those magnificent nautiloids and othocones who ruled the world during the Ordovician era.  Cuttlefish are one of the most intelligent invertebrates: their brains make up a substantial portion of their body mass, and their behavior when hunting, hiding, and courting is complex. The unusually shaped eyes of the cuttlefish are among the finest in the animal kingdom.  Their blood makes use of copper rather than iron to fix oxygen so it runs green.  All cuttlefish possess poisons in their saliva.  In fact the Pfeffer’s Flamboyant Cuttlefish is as toxic as the Blue-ringed octopus.

Camoflaged Cuttlefish

But why am I talking about these extraordinary mollusks during a week devoted to blogging about color? First of all cuttlefish are “the chameleons of the sea.” As I observed at the zoo, they can change color with a speed and facility unrivaled by any other creature. They use their mastery of color to camouflage themselves, to hunt, and to communicate with each other.  The animal’s existence literally hinges around the color-changing chromatophores in their skin. But the association of cuttlefish and color doesn’t stop there. Cuttlefish produce a dense ink which they squirt into the ocean to disguise their movements when frightened. This sepia ink, collected from the ink-sacks of common cuttlefish destined for the table, was prized for writing and for drawing during the classical era.  Many of the great histories and literary masterpieces of Greco-Roman thought were first penned in sepia ink. Although other inks took the place of sepia for writing, it maintained its place in the artist’s studio up until the late nineteenth century when it was supplanted by synthetic pigments.

sketches for "The Last Supper" (Leonardo da Vinci, 1495, sepia ink on paper)

This means that many of the masterpieces of draftsmanship were also created with sepia ink.  A particularly effective and pleasing style was to sketch something in watered down sepia washes and finish the details with black india ink. Like chartreuse, magenta, and vermilion, the name sepia itself has become synonymous with a color.  This reddish brown is famous in old masters pen-and-ink drawings, antique photos, and memory-hazed movie flashbacks.  Not only has this ink provided some of the most beautiful drawings in history, recent studies have shown that cephalopod ink is toxic to certain cells—particularly tumor cells, so we may not have written the last concerning sepia ink.

Giant Grave by the Sea (Caspar David Friedrich, 1806-1807, sepia wash and graphite on paper)

A model of Argonauta argo from the American Museum of Natural History

The paper nautilus, aka the argonaut (family Argonautidae) bears an uncanny resemblance to the majestic nautiloids of yore.   This resemblance becomes bizarre when one realizes that the resemblance is superficial.  The paper nautilus is no nautiloid at all.* It is in fact an octopus.  Its shell is not a true shell manufactured within an internal shell sack (as in other mollusks), but is rather an egg case secreted and delicately assembled by the female.  It is as though, instead of having a protective skeleton from birth, you were expected to build one and hatch your young inside of it.

Argonauts are pelagic predators, hunting planktonic mollusks, minnows, and small octopi and squid.  Like other cephalopods, they can change colors and alter their shape.  They move by means of jet propulsion.  Argonauts exemplify one of the most formidable traits of the cephalopod: intelligence. To quote Marcie Orenstein’s Marine Animals of Bermuda, “These animals often form associations with gelatinous marine species, utilizing them for food, locomotion, and protection.”  For example Argonauts are often found clutching the top of jellyfish and steering the latter around the ocean.  The Argonaut eats through the jellyfish’s mantle into its digestive tract.  It can thereafter rely on the jellyfish’s tentacles as a sort of fishing apparatus with which to catch prey (which it takes from inside the jellyfish’s gastral cavity).  The jellyfish further serves as a protective shield, for the argonaut’s predators, such as tuna and dolphins, tend to shun such hydrozoans.  Additionally the Argonaut gets a free ride for as long as its jellyfish remains alive.

We have pictures of this behavior! Argonauta argo atop the jellyfish, Phyllorhiza punctata. Photographs Copyright ©, Thomas Heeger, University of San Carlos, Philippines.

I mentioned above that only female argonauts build shells.  The male is a strange armorless dwarf, a tenth the size of the female.  One of the male argonaut’s arms, the hectocotylus, is specialized for mating.  The Tree Of Life Argonaut webpage describes this process, “At mating, the hectocotylus, which carries one large spermatophore, breaks out of its sac and then from the male body. The free hectocotylus invades, or is deposited in, the female’s mantle cavity, where it remains viable and active for some time.”  Georges Cuvier first discolvered the hectocotylus but mistakenly described the organ as a worm parasitic on the female argonaut.

Georges Cuvier's original illustration of the Hectocotylus of an Argonaut (Iconographie du règne animal de G. Cuvier, 1829)

The paper-thin calcareous shell of the female argonaut is truly an egg case.  It is shaped in a Fibonacci spiral for reasons which are unclear, however, like a nautiloid’s shell, it contains a bubble of air which the adult female nautilus manipulates for buoyancy.  Aristotle wrote that the Argonaut used its egg case and its flattened tentacles to catch the wind and sail, however there is no current evidence of such behavior (although cephalopods travel all sorts of strange ways).  When the eggs grow large in the shell case and hatch, the female is pushed out of her egg case and she dies.  Marianne Moore very beautifully described the female argonaut’s maternal solicitude in her poem The Paper Nautilus (while additionally cross-referencing the hydra, which we love at this blog).  Moore describes the female argonaut as a metaphor for creativity:

for she is in
a sense a devil-
fish, her glass ram’shorn-cradled freight
is hid but is not crushed;
as Hercules, bitten

by a crab loyal to the hydra,
was hindered to succeed,
the intensively
watched eggs coming from
the shell free it when they are freed

(From The Complete Poems of Marianne Moore. Copyright © 1961 Marianne Moore)

An Argonaut Illustration by the gifted Debby Mason

*Of the shelled nautiloids which once ruled earth, which teemed in countless numbers through the oceans of the Paleozoic and the Mesozoic, exactly one species is left–the magnificent pearly nautilus, concerning which, more anon.

A diorama portraying the seas of the Ordovician Period (from the Exhibit Museum, University of Michigan)

The Ordovician Period, the second period of the Paleozoic Era, took place from 488 to 444 million years ago.  During those 44 million years, the landmasses of earth were devoid of life except for hardy lichens, tiny algae, and a few lowly non-vascular plants. The oceans, however, teemed with diverse marine invertebrates and primitive vertebrates.  The ecosystems of these great shallow seas seem familiar–with colorful intermeshed filter feeders, grazing herbivores, and swift deadly predators. And yet the creatures are so alien as to make Ordovician reconstructions almost resemble another planet.  All of the creatures of a modern coral reef are replaced by strange analogs:  the dominant filter feeder were not corals but weird sponge-like animals—the archaeocyathids.  The grazers were conodonts and trilobites.  The predators were primitive sharks, huge scorpion-like eurypterids, and above all, the nautiloids–for the Ordovician was a time when cephalopods ruled the earth.

Clever mollusks with multiple tentacles, eyes, and a method of jet propulsion, cephalopods had evolved in the Late Cambrian from a snail-like ancestor.  Their taxonomy exploded in complexity during the Ordovician period.  They also left the shallow continental shelves to range across the pelagic ocean and to descend into the benthic depths.  The cephalopods of the Ordovician period were the nautiloids, animals which manipulated a bubble of air within a chambered shell to move up and down the water column.  They could grab prey with their many tentacles or retreat into their calcium-based shell. The family quickly exploded in complexity. To quote

At least ten different orders flourished at this time, all but one appearing for the first time during the early or middle part of the Ordovician.  This astonishing diversity included straight, curved, loosely coiled, and tightly coiled shelled types, and even one group (the Ascocerids) that in order to become lighter and more streamlined lost the a large part of their shell altogether.  These intelligent carnivorous molluscs replaced the Cambrian Anomalocarids as the dominant life form and top predator of the world’s ocean.  The biggest, such as the endocerids, attained huge size; with shells of up to 10 meters in length they were the largest animal that, up until that time, had ever lived.

Some paleontologists have expressed doubts about this magnificent ten meter endocerid shell.  But, even so, it is worth remembering that this measurement did not include the tentacles and the head of the creature.  These giant orthocones must have been formidable predators, living on nautiloids, eurypterids, and jawless fish.  The great monsters are believed to have had weak eyes (and could probably be avoided by staying shell-side of the behemoths).  However an even bigger problem faced the tentacled masters of that world.

A giant orthocone

During Ordovician times, the land masses that are now South America, Africa, Madagascar, Antarctica, India, South Asia, and Australia were all joined together as a supercontinent, Gondwanaland.  Over tens of millions of years Gondwanaland gradually drifted into the Southern Polar regions of the globe.  This resulted in heavy glaciation, which in turn caused rapid deep freezes and sudden interglacial warm periods—in other words, an ice age.  This great ice age caused the depth of the ocean to fluctuate wildly which brought a crashing end to the Ordovician and its dominant cephalopods.   The mass extinction which ended the Ordovician period was the second worst in the history of the planet (eclipsed only by the mass extinction at the end of the Permian period).   More than 60% of marine invertebrates went extinct (including whole families of mollusks).   This was but one set back for cephalopods.  The family has burgeoned and then crashed many times, but it marked the end of their time as apex predator.

Various Ordovician cephalopods, including the infamous Cameroceras trentonese, shown feeding on a hapless Aphetoceras americanum, while a quartet of Cyclostomiceras cassinense swim by (illustration by Stanton F. Fink).

I’m always surprised by how numerous and varied the cephalopods are.  A quick jaunt down the taxonomical branches of their family tree reveals marvelous creatures to delight even the most jaded marine biologist–and, we are still discovering new cephalopods all of the time!

Today’s post, however, is not a larger examination of squids and allied cephalopods (although I have been thinking about adding a “mollusk” category to this blog and embarking, to some small degree, on such a task), instead we are concentrating on a very specific and unusual behavior practiced by certain squid in dire circumstances—namely flying.

A Red Flying Squid (Ommastrephes bartramii) zips along above the Sea of Japan. Notice how the squid has altered its shape to become aerodynamic.  Original photograph by Geoff Jones.

Flying fish are well known for their aerial prowess, but flying mollusks (for such is, of course, what squid are) seem almost to strain credibility.  To imagine a cousin to the stolid clam whipping through the air propelled by jet propulsion takes temerity…or at least it would, if such behavior were not well documented.  Many different species of squid from around the world have been observed leaping out of the water to avoid heavier predators. In fact the common names of several commercially important squid reflect this: Spanish fishermen hunt for voladores “flyers”, Nototodarus gouldi is commonly known as the arrow squid, and Japanese Flying Squid (Todarodes pacificus) is a mainstay in Ika Sushi.

The Caribbean Reef Squid (Sepioteuthis sepioidea) propels itself above the waves with a jet of water.

These flying squid are not merely popping out of the water for a moment before returning: some of the creatures form their tentacles into a fan/wing then stretch out a membrane running along their body and actively flap the fins at the front of their mantle.  The Journal of Molluscan Studies cites an example of a squid flying 6 meters (20 feet) above the water for a total distance of 55 meters (180 feet) thus outdoing the Wright Brothers’ first flight!  I wonder if the ancient belemnites (extinct squid-like cephalopods of the past) were ever able to fly in such a way or if this is a new feature of cephalopod evolution–maybe in a few million more years we will have even more deft flying mollusks zipping around with the sparrows.

A cool acronym…or a harbinger of days to come?

Ye Olde Ferrebeekeeper Archives

July 2017
« Jun