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An Adult Female Blanket Octopus

“Blanket octopus” sounds like an endearing nursery game, but the blanket octopuses are actually pelagic hunters which have adapted to living in the ultra-competitive environment of the open ocean.  There are four species of blanket octopuses (Tremoctopus) which can be found ranging from the surface to medium depths of open tropical and subtropical seas worldwide.  Because they often live far from any land, some of the methods which other octopuses use to escape predators do not work very well for them.  Fortunately Blanket octopuses have adapted in their own unique bag of tricks.

An Adult Female Blanket Octopus

Blanket octopuses are named after the distinctive appearance of adult female octopuses which grow long transparent/translucent webs between their dorsal and dorsolateral arms.  Blanket octopuses use these webs as nets for hunting fish, but they can also unfurl and darken their nets in order to appear much larger than they actually are.  Since blanket octopuses do not produce ink and can not camouflage themselves as rocks, coral, or sand, they rely heavily on their blankets.  As a last resort they can jettison the blankets as a decoy and jet away while the confused predator attacks the highly visible membranes.

Blanket octopuses exhibit extreme sexual dimorphism.  Whereas the female octopus can grow up to 2 meters (6 feet) in length, the male octopus is puny and does not grown longer than a few centimeters (1 to 2 inches).  Males store their sperm in a modified quasi-sentient third right arm, known as a hectocotylus.  During mating this arm detaches itself and crawls into the female’s reproductive vent.  As soon as the hectocotylus is detached the male becomes unnecessary and dies.

Male Blanket Octopus

Tiny males and immature females do not have blankets, but they utilize another trick to protect themselves.  Because they hunt jellyfish and other hydrozoans, the little octopuses are immune to the potent venom of the Portuguese man o’war.  The octopuses tear off stinging tentacles from the man o’war and wield them in their tentacles like little whips to ward off predators.

An amazing illustration of a blanket octopus sheltering in a Portuguese man o’war’s tentacles

A very lovely photograph of an octopus kite by Nigel Bence

Ferrebeekeeper has written about actual flying squids which dart above the water waving their lateral fins to extend their gliding ability.  But real squid are not the only cephalopods that one sees in the skies–especially around springtime.  Two of the classical shapes for kites are squid & octopus shape.  The squid’s finned oblong shape, and the octopus’ round shape are perfect for balance and for catching the wind.  The dangling tentacles act perfectly as multiple tails. This spring has taken a cold gray turn—at least in New York, but while you are inside planning what to do during May, perhaps you should build some octopus and squid kites.  Here is a little gallery of images from different kite festivals and kite makers around the world.

A Commercially available Octopus kite/kit

Like squids and octopuses, none of the kites I had when growing up ever lasted long (well none of the ones I actually flew).  The beautiful range of mollusks suspended on the wind in the sky makes me wonder if I have any time to get out some dowels and crepe paper and build some more kites [sadly you do not have any such time—ed.].  As the soon as the  weather clears up again, I hope you enjoy some kite flying!

Sealife Mosaic from "the House of the Dancing Faun" in Pompeii (ca. 1st century AD)

So much of Roman artwork is lost.  Except in remarkable circumstances, Roman paintings, textiles, and drawings were too fragile to survive the long centuries of neglect.  Almost all are now long gone.  Fortunately the Romans were masterful mosaic artists and mosaics are durable. Many mosaics concerning all sorts of aspects of classical life have lasted through the millennia.  Some of these tile artworks present the loves of gods or the wars of men but quite a few are more humble and show the aftermath of a banquet or fishermen hauling in a day’s catch .  Since Romans ate a huge amount of seafood, it is no surprise that many mosaics showcase mollusks of one sort of another.  Here is a gallery of Roman mosaics featuring octopuses, squids, bivalves, or snails.  I have tried to add as much information as I could but some of the photos I found were poorly labeled

Marine Life Mosaic from House viii in Pompeii demonstrating the vermiculatum technique (ca. 2nd century BC)

Detail of a Roman bath mosaic depicting a murex. (ca. late second to early first century BC)

Floor mosaic from "House of the Faun" Pompeii: Cat with bird, ducks, and sea life.

Ancient Roman Mosaic Prtraying Sealife from the British Museum

Triton with an octopus and squid (Forum Baths, Herculaneum)

Roman Mosaic of an Octopus

Modern mosaic makers were inspired by the Roman example and flamboyant cephalopods are a major theme of contemporary mosaics as well as ancient ones.  Here are some modern octopus and squid mosaics for millionaires’ swimming pools, elementary schools, or even everyday bathrooms.  Enjoy!

Modern copy of a Roman era mosaic from Milreu, Portugal

A Kraken for the bottom of a swimming pool (by Laurel Studios)

Octopus Mosaic for a public school

Contemporary Octopus Mosaic

A squid mosaic in downtown Pittsburgh, Pennsylvania

Octopus Mosaic from Seattle Country Day School

Navigation Mosaic by Mia Tavonatti

Tomorrow evening will feature the first game of the Detroit Red Wings season. This bold team of lovable* misfits will take to the ice against the hockey team from Ottawa–the name isn’t listed but they have some sort of classical footsoldier as a mascot so we’ll call them the Ottawa Hopelites. [maybe you should understand at least something about hockey before writing about it—ed.]

Anyway, even more exciting than the actual game between the Redwings and the Hopelites is the unofficial mascot of the Red Wings.  In a post concerning mollusk mascots from around the world, alert reader Ryon Lancaster commented that we had overlooked the mascot for the Detroit Red Wings, a purple hockey-playing octopus named Al.  Apparently the legend of Al started back in April 15, 1952, when fishmongers Pete and Jerry Cusimano decided to throw an octopus onto the ice at Olympia Stadium.  The eight tentacles of the cephalopod were meant to mystically represent the eight victories required to win the Stanley Cup (the ice hockey championship trophy). Sure enough the magical mollusk brought the team to championship victory and ever since then fans have thrown deceased octopuses onto the ice at their home stadium—especially during playoff matches.  As the Red Wings’ octopus tradition deepened, the purple mascot Al coalesced from fan art and from oral tradition. Al takes his name from a former building operations manager, Al Sobotka, who exhibited great elan whenever he removed octopuses from the ice.  Apparently Sobotka had a special octopus twirling technique which whipped the fans up (albeit at the expense of distributing octopus particles onto the ice and the crowd).

As you might imagine, NHL officials have mixed feelings about this fan tradition. In 2008 hockey officials banned Al Sobotka’s octopus twirling and the duty of removing octopus corpses has fallen to linesmen and icegirls.  The stadium itself added a large octopus prop during the 1995 playoffs.  This huge octopus totem was ceremonially raised to introduce the team.  Later on it was given glowing red eyes (which light up during goals), a number eight hockey jersey, and a broken tooth.  Since it now requires winning 16 games to win the Stanley Cup, there are two Al the octopuses hanging above the ice at playoff time.

Naturally a number of other teams have tried to imitate the seafood throwing craze including San Jose, (where fans threw a shark), Boston (lobster), and Vancouver (Salmon).  The only other team which appears to be establishing a continuing tradition of throwing deceased aquatic creatures on the ice is the Nashville Predators (why does Nashville have a hockey team?): predators fans have been known to throw large catfish onto the ice.  A weary ice attendant, Jessica Hanley is reported to have said “’They are so gross. They’re huge, they’re heavy, they stink and they leave this slimy trail on the ice. But, hey, if it’s good for the team, I guess we can deal with it.”

*actual boldness and lovability may vary

Woodblock prints of ages past show giant octopuses ripping apart boats and feasting on sailors like popcorn.  These artifacts of ancient sea-lore make for rousing images, but they are quite wrong:  octopuses are fierce and cunning hunters but they present little danger to humans—with a noteworthy exception.  The truly dangerous octopuses are not giant monsters (perhaps the artists of yesteryear were thinking of the mighty giant squid?) but rather tiny jewel-like beauties from the genus Hapalochlaena which includes only three or four species.  Known as blue-ring octopuses the tiny creatures swim in tide pools and shallows of the Indo-Pacific Ocean from Japan down to Australia (where they are most prevalent).  Blue-ringed octopuses live on shrimp, crabs, minnows, and horseshoe crabs.  They are tremendous hunters who use camouflage, stealth, and guile to catch their prey.  However, these tools pale before their greatest weapon: the little octopuses are among the most poisonous creatures on planet Earth.

(photo by Aluki from Flickr)

Like the flamboyant cuttlefish, the blue-ringed octopus does not like to bite without giving warning but advertises its toxicity with vivid coloration.  The octopus can conceal itself with tremendous prowess however, as soon as it becomes aware of a predator or some other threat, it dials up its coloration changing from muted reef tones to brilliant yellow with iridescent blue rings.  If you see something like this in the ocean, for heaven’s sake don’t touch it.  The octopus’s warning colors let ocean predators know to leave it alone but immediately attract humankind’s magpie urge to grab shiny things.  Although blue-ringed octopuses are good natured and have been known not to bite people who were provoking them rather intensely, their bites have caused more than seventy recorded fatalities in Australia. The octopus has a tiny beak and often a victim does not realize they have been bitten until they began to fall into paralysis and their respiration starts to fail.

Argh, I said don't touch it

The venom of the blue ringed octopus is a complicated pharmacological cocktail which includes tetrodotoxin, 5-hydroxytryptamine, hyaluronidase, tyramine, histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine. The most active ingredient tetrodotoxin blocks the sodium channels which conducting sodium ions (Na+) through a cell’s plasma membrane.  This causes total paralysis for the octopus victim, however if clever and persistent rescuers are present at the time of the bite they can rescue the unfortunate soul with continuous artificial respiration.  This is no small matter as bite victims are often rendered completely unresponsive by the paralytic victim.  Although completely conscious they are unable to communicate in any way or even breathe.  If artificial respiration is initiated immediately and continued until the body can metabolize and eliminate the toxin, bite victims can survive (although it sounds like rather an ordeal).

Blue ringed octopuses are tender and solicitous mothers.  The mother octopus lays a clutch of approximately 50 eggs in autumn which she incubates beneath her arms for about six months (during which time she is unable to eat).  When the eggs hatch, the mother octopus dies. The baby octopuses reach sexual maturity in about a year.  Despite their cleverness and beauty, the animals are as ephemeral as they are deadly.

Under its mother's watchful eye a baby southern blue-ringed octopus (Hapalochlaena maculosa) emerges from its egg.

An octopus or squid theme jar from the Knossos Palace in Crete (ca. 1500 BC)

Since the last two posts concerning mollusks have also involved the classical Mediterranean world (where cuttlefish ink was used for writing/drawing and murex mucous was employed as a costly dye), I am going to continue the theme by presenting a gallery of octopus vessels from ancient Greece.

A Mycenaean Octopus Vase (from beyondbooks.com)

Most of these vessels are from the Minoan culture which flourished from 2700 BC -1500 BC or from the Mycenaean city states which were most successful between 2000 BC and 1100 BC (when an incursion of mysterious aggressive “sea people” apparently destroyed the great palace kingdoms). Such vases and jars were made by trained craftsmen and were prized throughout the Levant.

Stirrup jar with octopus, (ca. 1200–1100 b.c.; Late Helladic IIIC, The Metropolitan Museum of Art)

Vase of the Late Minoan I Period (about 1600-1100 B. C.) found on Gournia, Crete Courtesy of the Metropolitan Museum of Art."

Minoan "Palace style," vessel (ca. 15th century BCE, Athens National Museum)

Because we only know tantalizing fragments about life in ancient Crete or in the Mycenaean palace states, the artifacts from that age have been subject to much conjecture and speculation.  These lovely octopus vases have led some thinkers into believing that Minoans worshipped the sea and the creatures therein.  Other scholars have conjectured that the ancient Cretans looked to octopus tentacles as inspiration for that characteristic Minoan architectural conceit, the labyrinth.  The real symbolic or ritual purpose of the octopus motif remains unclear and probably always will.  What is certain is that the vases, drinking vessels, and jars are quite lovely.  The octopus motif originated around 1500 BC and by the Minoan period the so-called “marine style” of decorating pottery had become even more prevalent and diverse.  Some ceramics were covered with fish, octopuses, dolphins, and crabs.  In fact there was even a vessel covered with murexes. Perhaps these people simply liked octopuses and sea creatures. I can certainly understand that motivation!

Terracotta rhyton painted in "Marine Style" with murexes (Zakros, Late Minoan IB, ca. 1525/1500-1450 B.C.) (Courtesy Onassis Public Benefit Foundation)

Rhyton, drinking vessel with painted octopus (From the Aegean, found in Ugarit "Minet-el-Beida", Syria. Late Bronze. Terracotta)

Minoan Amphora w Octopus Motif , New Palace Period , Knossos , Crete

Stauroteuthis syrtensis (photo by David Shale and Claire Nouvian)

One of the reasons I chose mollusks as a topic is to illustrate how diverse life on our own planet is. The mollusks are an insanely heterogeneous phylum of creatures and they have been successful around the globe for the last 540 million years (at least). Even today in the ultracompetitive Holocene world, mollusks thrive just about everywhere.  To illustrate this point I am showcasing the enigmatic deep water octopus Stauroteuthis, of which two species are currently known.  These octopuses are only found more than 700 meters underwater in the Atlantic Ocean.  Although they are most common around 2 kilometers beneath the surface the creatures have been spotted as far as 4 kilometers down.  The Stauroteuthids are small benthopelagic octopuses (they are free-swimming but live in close proximity to the ocean floor).

(photo by David Shale)

The Tree of Life Web Project gives us the following overview of Stauroteuthid morphology:

Stauroteuthids are peculiar, gelatinous cirrates with a mantle opening that forms a complete tube around the funnel. They also have peculiar gills and internal shells and a large web that is nearly equally developed between all arms. When observed from submersibles, this octopod commonly has its arms and web formed into a bell-shape (bell-shape posture). Sometimes when the octopod is disturbed, it will inflate the web and draw the arms together at their tips to form a “balloon” with the arms and web (balloon posture). These postures are thought to be involved in feeding and/or defense.

That is nearly all we know about them—it is difficult to study creatures which live 2 kilometers underwater. However I have left out the most exciting fact: the Stauroteuthids are bioluminescent.  Certain muscle cells around the suckers have been replaced with photophores which allow the Stauroteuthid octopuses to light up their eight legs like plane runways.  The purpose of this luminescence is unknown but it is believed to be for predatory purposes (the lights are thought to direct prey to the octopus’ beak). Possibly the lights also help the octopuses to find and communicate with mates.

Bioluminescent Suckers (photo by ORCA)


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.

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