LO AND WOE, for I have been negligent! We are in the midst of a holiday, perhaps the most important of holidays. No, not that Columbus' Day foolishness, but the INTERNATIONAL CEPHALOPOD AWARENESS DAYS. The Cephalopodiatrist, TONMO,The Cephalopodcast and others are repping proudly and head-footly, I am doing my best to boost their signal.
I'll be here. Waiting.
Photo by Mike Bartick.
So what are the International Cephalopod Awareness Days? Directly citing the Cephalopodiatrist (brilliant name, btw), they are:
Thursday, October 8 - Octopus Day, for all the eight-armed species
Friday, October 9 - Nautilus Night, a time for all the lesser-known extant and extinct cephalopods
Saturday, October 10 - Squid Day/Cuttlefish Day, or Squidurday, covering the tentacular species
Now I must decide the method in which I should celebrate these most grand of creatures. I thinking possibly commemorative baked goods. If I was crafty in a material direction, I would consider making a head-mounted squid. This is completely unrelated but amazing.
Even Chun-Li has a squid hat.
Perhaps I should write about the ghosts of Cephalopods Past, those Paleozoic wonders whose remaining impressions of hard bits we can only gawk at in simultaneous sadness that they are no longer with us/happiness that we are not their prey.
Perhaps I should do a tribute to the cephalopod in fiction. Why does the image of dread Cthulhu stick with us so stubbornly, far more than any other of Lovecraft's creations?
DECISIONS AND PRODUCTS TO COME LATER. IN THE MEANTIME, MEDITATE ON ALL CEPHALOPODS, GREAT AND SMALL. ALSO, FEEL FREE TO THROW MONEY IN THE GENERAL DIRECTION OF OCEAN BLOGGERS UNITED FOR EDUCATION
A) You'll soon be getting a new post only three months after the last one entitled "B is for BATOIDS". I know you are literally oozing with excitement so you should probably go get a mop and take care of that, it'll stain the carpet.
A spotted eagle ray, who is indeed a batoid.
B) It's time for the DonorsChoose Blogger Challenge 2010! www.donorschoose.org is one of my favorite educational charities, especially since I used to work in an elementary school and:
i) they are poor, educational funding the U.S. is a trainwreck
ii) I made it one of my duties to "transmit the joy of science to students" in addition to being a literacy tutor.
I was more successful than I expected, possibly because I have zero shame and behave like an eight-year-old when it comes to things that I am excited about. I probably made a bunch of adults uncomfortable too but maybe they should learn to not be joyless husks every once in a while.
Anyway, not a lot of noise has been made yet and I am currently waiting to throw my lot in with the ocean science people. PZ Myers and his lot already have their widget up, I'm just biding my time.
I'm also feeling the drive to do some sort of ocean-related top ten list. One would suggest that it would be natural for me to do one on cephalopods, but that's so been done. Of course, since it is the month of Halloween, I could do another "You call these horrors of the deep? Here are REAL horrors of the deep and btw the nature is amoral therefore this is not an excuse to kill sharks in the style of the Mexican Navy." Because you KNOW all people are going to do this month is post pictures of anglerfish despite that the average anglerfish is about as terrifying/provides as much physical resistance as a bowl of pudding.
Wow, I am terrible at updating lately. Things are probably going to continue to be not-so-great for a while because I'm in the preliminary stages of relocating from Michigan to Texas; after Texas I'll possibly be relocating internationally for work, but let's not worry about that right now. Instead, let's worry about other stuff like:
Also relevant is that June 11th was World Ocean Day and the 100th anniversary of the birthday of Jacques Cousteau. Like so many other folks who blog about the sea, Cousteau definitely impacted my love/interest in the ocean.
My mother was and has always been excellent about bringing my brother and I to the local library. When I was 4-5 or so I discovered a series of books by Cousteau on the shelf and proceeded to check them out obsessively, a habit I totally never repeated later in life (bless you, Madeleine L'Engle). It was a cycle, we'd check some of them out and then I'd recheck them out as long as they'd let me. I couldn't even read at the time, but it didn't matter, I'd make my mother or father read them to me.
A nudibranch! I used to pronounce the "-branch" as in the things that
grow out of trees, not with a final -k. I am reasonably sure that this will be held
against me at some point.
In this way, my childhood was filled with nudibranchs, eels, basking sharks, barracudas, tuna, squid, giant clams, etc...and this is completely ignoring marine mammals in the equation, which I think may be as universally appealing to children as dinosaurs. I wish I could pinpoint which books they were, they were definitely not aimed at children. They must've been older as this was around 1989-1990 and they weren't terribly new back then.
But yes: Jacques Cousteau, we salute and will continue salute you for having such an impact on so many people who love the ocean now, due in part to your efforts to spur our imaginations oceanward. Maybe astronomers have similar feelings about the venerable Carl Sagan?
Actually, I've decided that this post will be devoted to something near and dear to the hearts of Japan and the United States, though in completely different formats: TUNA.
I'd wager that most folks in the U.S. take tuna, the nationally most-consumed fish, for granted because this is what tuna looks like in the national consciousness:
I honestly wonder how many U.S. folk who don't have reason to spend much time around fish know what a tuna looks like. For the record, the fish that the meat in the can came from looked something like this:
I don't know if you can tell from this distance, but the first thing that caught my eye about the fish (a skipjack tuna) were the rows of little knobs running near the tail. These knobs are called "finlets" (and "tails" in fish are actually called "caudal fins", but we can have fish anatomy lessons another day) and mark the tuna as a member of the Scombridae family, which is where mackerels and wahoo are also categorized. Note that finlets are not exclusive to this family, but they're still distinctive.
My oceanographer professor (when he wasn't talking about catching sea bass in Baja) occasionally referred to tuna as "horses of the sea" because they are built for speed and gratuitous face-rocking.
Yellowfin tuna are faster than you.
Unless you happen to be a cheetah.
AWESOME TUNA FACT: They're...not exactly cold-blooded. They're not exactly warm-blooded either, but they're certainly more warm-blooded than most fish. The term "cold-blooded" means that an animal is unable to regulate its body temperature; its body temperature is the same as the temperature of its surroundings. The LSU AgCenter says it more succinctly than I can:
Tunas (and a few sharks) have developed the ability to control their body temperature through a network of veins and arteries called a "rete mirabile" that traps (and dumps) body heat. Even smaller tunas can maintain temperatures 50ºF higher than surrounding water temperatures...for most cold-blooded fish, the colder the water and therefore their body is, the slower and more sluggish they are. Tunas' warmer body temperatures speed up the chemical reactions in their body that produce energy and allows their muscles to contract more quickly. This provides faster swimming speeds and increases their endurance...
Compared to other less active fish, tunas have hearts that are ten times larger for their body weight, pump three times more blood, and have blood pressure three times higher. They also have a much higher proportion of red muscle in their bodies than the average fish, which allows them to cruise at higher speeds more efficiently.
http://www.seagrantfish.lsu.edu/biological/mackerels/yellowfintuna.htm; text bolded by me
If you are thoroughly entranced by the particulars of scombroid physiology, the University of California has a treat for you! Very thorough examination of several scombroids, both inside and out. Don't worry, they're polite and don't rudely shove fish viscera (fishera?) under your nose, you have to click links if you want to see guts.
But yeah, have you ever wondered why tuna steaks look like this (top) and say, catfish fillets (bottom) look like this?
DING DING DING: Tuna have more red muscle than other fish in order to fuel their eternal swim, not unlike some shark species that must utilize ram ventilationto respirate. To burn the oxygen required by these hefty piscine muscles, tuna have myoglobin, a type of protein, in their muscles. Myoglobin actually forms the pigments that gives raw "red" meat its color, and is also responsible for making red meat that has been frozen turn brown.
Because consumers enjoy their red meat really red ("bright red"="fresh" in the human brain), this has led some dealers of both tuna and red meat to treat their products with processes that prolong this red color; one way to do this is to expose the meat to carbon monoxide before it's frozen. As the venerable Alton Brown says, this isn't a bad thing in theory, but it can be unscrupulously used by the powers of darkness.
Of course, not all tuna are bright red, across both individuals, species and parts of the body. The sushi/sashimi eaters in the crowd will know that otoro, meat from the fattiest part of the bluefin tuna, is actually quite pale because well, it's fat:
Not the pieces that look like watermelon.
So how do they use all these thick muscles that I keep going on about? In conjunction with their highly streamlined bodies. As I research, the word that keeps coming up to describe the body of the tuna is "missile". They have:
grooves along the sides of their bodies to tuck their pectoral fins into place
eyes that are flush with their bodies, tunas don't have time for protruding eyes slowing them down
a stiff body and skull to increase speed
forked crescent-shaped (lunate) tails optimized for rapid oscillation i.e. going really fast
Speaking of sushi, since Japan's consumption of tuna is highly relevant to this conversation, we should probably talk about it a bit. First, the Sushi FAQ will give us a brief education about the particular cuts of tuna used in sushi. We also have this beautiful image if you prefer a graphical approach. Available in both Traditional Chinese characters and Romanized Japanese!
While there nine species of true tuna (fish who belong to the genus Thunnus), there are 9-10 others that belong to the greater tuna family and happen to have the word "tuna" in their names. The skipjack tuna, the fish in your can (unless you buy "white meat" tuna, which is albacore) is actually a member of this latter category; don't worry though, it's still a scombroid. The most well-known members of the tuna family include the albacore, yellowfin (ahi), blackfin, bigeye and several species of bluefin tuna.
However, the AVERAGE weight of the Atlantic bluefin tuna (no, I'm not giving you averages for every subspecies of bluefin tuna, live with it) is around 550 lb/250 kg, with a length of 6.5 ft/2 m. Regardless, even a small mature bluefin is still a Large Fish.
Rows of frozen tuna torpedoes at the Tsukiji fish market in Tokyo.
More hydrodynamic than when actually alive!
Bluefin tuna are also Not in a Good Way. In addition to them being good eats pretty much everywhere, Japan has a special fondness for the bluefin. In addition to eating them with enthusiasm, there is a great deal of money to be had in supplying them. As of January 2010, the record price for a single bluefin tuna at Tokyo's premier Tsukiji fish market (which I really need to post about too) sat at a cool 16.28 million yen, slightly over $175,000 US (depending on the day), for a 511 lb/232 kg individual. They are very serious about their tuna. So serious that the estimates I've seen suggest that Japan consumes 70-80% of the world's Atlantic and Pacific bluefin tuna catch.
As is so often the case, demand is exceeding supply: this level of consumption is simply not sustainable. We are seeing the bluefin tuna go the way of Atlantic cod and salmon; it's more disturbing yet because while there is no commercial fishing of wild Atlantic salmon and cod (check the point of origin of your salmon; if it's Atlantic salmon, I can almost guarantee that it was farmed off the coast of western South America), bluefin is still being commercially overfished.
Zoom! TUNA ALERT
There have been some attempts at farming bluefin tuna (or "ranching", both terms sound silly), but farming a large voracious fish that literally has to keep moving or it will die? Um, good luck with that. For the interested, Wired also posted an article about 11 months ago about the myriad joys of tuna ranching.
I don't know what the fate of the bluefin tuna will be. Like pretty much everything that lives in the water, it was sacrificed to the almighty dollar at CITES in Doha this year. While the possibility of a ban was presented and voted down, Japan pretty much said that bluefin tuna aren't that endangered, despite a wealth of evidence from a wealth of sources that says that Japan is apparently pulling its numbers directly from its anus, probably still a little poopy.
Just in time for me to post this entry, there's a 9-page article on the New York Times that covers much of what I'm talking about: Tuna's End. I suggest reading if you have the time/interest. If you REALLY want to read more, marine conservationist and artist Richard Ellis has just the book for you (and me!): Tuna: A Love Story.
You're going to have to earn that albacore, son.
So uh, what to do? I strongly suggest not eating bluefin, yellowfin or bigeye tuna, for one. The Environmental Defense Fund provides both a recommended seafood list and a Sushi Selector for those of you having trouble with this blast to the sushiverse that others are dealing with by burying their heads in the sand as quickly as they can. The Monterey Bay Aquarium also has seafood watch resources. Ocean and environmental conservation organizations will often provide action alerts to you to contact legislators and politicians regarding tuna regulations; Oceana comes to mind, but there are many others out there. I know that Greenpeace has been doing some work regarding tuna seining (referenced the NY Times article) and putting pressure on retailers who market unsustainable species of fish; if you agree with their tactics, it may be another venue for you.
EDIT 07/01/10: A commenter at BoingBoing drew my attention to the inaccurate comment I made implying that all sharks must continually swim to respirate. This error has been corrected. I appreciate having my attention drawn to this so that I don't make an off-handed factual error and provide inaccurate information, which is the opposite of my intent.
Given it's been well over a month since I last updated, I think we need to review the news in the fish blogosphere (<- I hate that word). Remember, if I link something I found it interesting/entertaining enough to read!
I DID NOT COME HERE FOR THIS
The colossal squid (not the same as the giant squid; some of the classy folks at TONMO have even prepared a fact sheet specifically about this topic) lost some street cred with the release of a study recently, claiming that even though it has nightmare-inducing swiveling hooks on its arms, it's actually kind of lazy. However, Mara Grunbaum at Arch-Anemone has written in brave defense of these lazy/terrifying/totally k-rad creature.
There's a good post up at Hectocotyli about zoophilia; "bestiality" has such a stigma. No, seriously, it's an interesting post on human sexuality as it relates to animals. It's probably NWS due to obligatory octopus shunga, but you might be able to get away with the "But it's ART!" excuse if you have a prudish boss/coworkers.
Apparently a six-gill shark was caught 30 km up a river in Tasmania. Six-gill sharks (most sharks have five gill slits), like so many creatures I love, are old-school. I will write more on them later, but suffice to say that six-gilled sharks are generally found in the opposite of rivers, that is in deep sea waters, so this is kind of weird. Maybe it is bad at directions.
...well, I know I hold my fish in my hands when I'm cleaning the aquarium, it's by far the best place to put them. At least we have this boy's experience for us, the fish-holders, warning us of the dangers of holding fish near one's urine stream while voiding one's bladder.
And of course, I would be remiss in ignoring the biggest story: the oil well currently ejecting valuable filth into the Gulf of Mexico, thus causing problems for many, many organisms. It is also causing problems for Louisiana, which is a Problem because I myself am from coastal Louisiana; I do not take kindly to this sort of business causing problems from my frequently beleaguered home state.
Unfortunately, me flailing and yelling horrible things at the well/oil industry/global economy/various governments isn't going to stop anything. I'm sure me spilling more virtual ink on the situation will do much. If you're interested (which you should be), I would suggest keeping up with the situation at Deep Sea News, they seem to have a steady and constant finger on the pulse of the situation.
NOT-SO-FUN OIL SPILL FACT: What do they clean the poster children of oil spills (water fowl) with? Diluted Dawn dish soap!
If you go on the Internet, you may or may not have seen this image that is making the rounds through mainstream online media:
Apparently this got posted to Reddit in which people commenced with their "OMG WHAT IS THIS KILL IT WITH FIREing" that you may or may not be familiar with. You, gentle reader, almost certainly thought, "Pish posh, anyone can clearly see that is a giant sea isopod they've strung up so rudely on boat...stuff." If you didn't, that's okay, you still have my eternal gratitude for reading this.
Continuing on, the good folks at Deep Sea News came to the rescue and educated people hard; you can read the chronicle here, in which they staunchly defend our brave isopod from the slander of the Internet. However, rampant misinformation of the occasionally-amusing type is still being spread so your friendly Uncle A. (<--me) is here to learn you even HARDER.
-Despite what you may have heard on AOL giant sea isopods are not roaches. The lowest taxonomic level to which they both belong is the phylum Arthopoda.
To put that in perspective, humans and dogs are closer together on the taxonomic tree (we both belong to the Mammalia class) than giant isopods (Bathynomus)and cockroaches (Blattaria) are. Organisms closer to isopods include the usual restaurant suspects (crabs, lobster, shrimp) krill and the like.
HERE IS A DIAGRAM AND FLASHBACK TO 7TH GRADE SCIENCE CLASS. Organisms are divided into six large categories, called kingdoms or regna:
1) Animalia (mammals, insects, primates)
2) Plantae (flowers, trees)
3) Fungi (mushrooms, mold)
4) Protista (amoeba, the awesomeness of slime molds, algae, diatoms)
5) Archaea (most famous for extremophiles, i.e. the blue/green stuff that lives in hot springs in Yellowstone, the things that live your in guts RIGHT NOW!!!1)
6) Bacteria (most famous as pathogens; the LIVE ACTIVE CULTURES advertised on yogurt). Yes, six; I'm from the U.S. so we'll be dealing with the U.S. system.
Organisms are classified by a number of different characteristics as being more or less similar to one another in terms of evolutionary biology. The further down you go on the taxonomic staircase, the more specific you are. For example, the taxonomy of a yellow-bellied marmot, a creature near and dear to my heart (SPOKANE MARMOT POPULATION HOLLA), would look something like this:
Spokane's greatest natural resource, upping property AWESOME values by
CLASS: Mammalia (it is a mammal; it gives birth to live young and
breastfeeds them) ORDER: Rodentia (it is a rodent, which are characterized by
having by two sets of continuously growing incisors
which must be kept short by gnawing on stuff).
Notice that humans diverged from marmots below
the CLASS level; until then we're together. FAMILY:Sciuridae (it is a squirrel)
SUBFAMILY: Xerinae (it is a ground squirrel)
GENUS: Marmota (it is a marmot)
SUBGENUS: Petromarmota (it is a marmot that lives in
rocky areas)
SPECIES: Marmot flaviventris
If there are subspecies, they go there at the bottom. But yes, if you want to know what a given organism is most closely related to, CONSULT YOUR TAXONOMY! For fish we have the venerable FishBase as a resource for this.
Taxonomy lets you do things like find out that the langostino lobster in Long John Silver's "Lobster Bites" are not actually lobster, but a "squat lobster". Which look are related to porcelain crabs and hermit crabs, which are also not actually true crabs. ... ...awkward. Does it make them any less tasty? No, but they're still not lobsters.
Same with the obligatory market labeling of certain types of catfish as "tra" or "basa" courtesy the shining paragon of science and rationality that is Senator Trent Lott; I am embarrassed to have his state border my own, but it's not like Louisianan politicians aren't embarrassing me/themselves/the entire state on their own. This was done in an effort to appease U.S. catfish farmers who felt that they were being undercut.
I have personally seen websites and store displays describe basa and tra as "similar to catfish". This is dead wrong, because BASA AND TRA ARE CATFISH. Yes, they belong to the Pangasiidae family of catfish, whereas the catfish native to North America are from the Ictaluridae family. This does not make them "not catfish", however; ALL fish that belong to order Siluriformes.
Chum (aka keta or dog) salmon with some dude. You may see these guys marketed under the name "silverbrite" because nothing says "tasty fish" like something that sounds like it's silverware cleaning product. Especially since the fish is very clearly silver.
I will stop now, because I could go on for days about my anger regarding the "market" names of fish and nobody wants that (yet).
Actually, this brings up something else that I'm sure all of you know, but I'm going to throw it out there. Whenever there are pictures circulating on the Internet (possibly forwards from your great-aunt) of various creatures, don't necessarily believe the caption. Examples include deep-sea creatures allegedly washed up by the Indian Ocean tsunami of 2004 (HINT: Tsunami do not work that way) and well, plenty of others.
One my mother asked me about described an animal in a picture as a "giant catfish" when it was actually a juvenile whale shark (READ: catfish do not look like whale sharks and whale sharks are very distinctive).
E-mail forwards are not necessarily known for their standards to accuracy so I would suggest applying a healthy degree of skepticism and seeking further information from reliable sources whenever one receives such things.
*=Yes, I am aware that the biological taxonomy hierarchy is changing/the one I've provided may not be 100% correct at this moment in time. However, I figure that this breakdown would be the most useful while avoiding splitting hairs about microbiology/clades/etc.
I've been meaning to rage about the results of the recent CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) meeting for a few days now. CITES is an international conservation agreement between (as of 2009) 175 nations that meets once every three years to discuss various protections for flora and fauna.
The results of the most recent meeting would probably be best conveyed by the participants writing "SCREW THE OCEAN" in a snowbank with urine. Christie Wilcox at Observations of a Nerd writes about it in a much more dignified manner than I would, but here at the main points:
-Protection/regulations for eight species of shark did not pass. The majority of sharks being commercially caught are being taken for their dorsal fins.
I'm pretty sure these look better on sharks.
-Trade ban on Atlantic bluefin tuna failed. Bluefin (the shining stars of sushi and sashimi) are being eaten out of existence; this is only about Atlantic stocks, Pacific stocks are in a bad way as well. You can largely thank Japan for this one; for having such a thing for tuna, you'd think it'd be concerned about their conservation. APPARENTLY NOT
-Trade ban on polar bear products (they count as marine mammals, hush) failed.
I've heard that tigers made out pretty well (given some people think parts of them are good for the old E.D.), but that's small consolation. There are a good number of resources out there that discuss all this in more detail if you're interested, but the heart of the matter is that short-term gains from trade apparently trump conservation and sustainability for many members of CITES.
One would hope that with everybody and their grandmother howling about "sustainability" and "green" everything people would've picked up on what happens when demand exceeds supply, but this seems to be one of those things that can be conveniently compartmentalized away when the situation (PROFIT) calls for it.
I could go into more detail (and probably will later) but it upsets me greatly that so many posts are about how this or that organism is endangered, nearly extinct (goodbye dear baiji; kind of surprising given people usually crap themselves over marine mammals. Maybe just not weird-looking river dolphins?), has a threatened habitat, etc.
In closing, I strongly encourage all (any?) readers to do what you can in terms of supporting oceanic (and frankly all types of environmental) conservation. If you read this thing regularly you've noticed that this blog is a way for me to share my lifelong love, fascination and enthusiasm for marine life; think of it as an exceptionally dorky love letter to the sea* that I insist on reading to everyone I meet. It is my goal to infect others with this enthusiasm; this will become much more difficult the more damage these valuable ecosystems sustain.
Enjoy this lovely video of chimaeras, fantastic little cartilaginous shark-esque fish also known as ratfish, rabbitfish and ghost sharks. Don't worry, they'll get their own entry; I can never ignore something with grinding plates for teeth.
The male Argonaut is an insignificant shell-less creature, fond of retirement, solitary and rarely seen. When the tender passion seizes him, as he rocks on some sunny wavelet, far from female society, he does not go in search of a wife, but with Spartan courage, detaches one of his eight hands (or arms) and consigns it to the deep, in the hope that some tender hearted individual of the other sex will fall in with it and take it under her protection.
Dall, W.H. (1869). Notes on the argonaut. The American Naturalist, 3(5), 236-239.
Diagram of the male argonaut; a is the octopus, b is the hectocotylus.
Nicholson, H.A. (1880). Manual of zoology. St Andrews, Scotland, UK: William Blackwood And Sons.
One subject that is always of interest to me is the sheer diversity and gory details of the many reproductive practices found in nature*. That (and winter recess) is what brings this entry to this evening: the semi-autonomous phallus of the argonaut.
"Hectocotylus", for our purposes, means "octopus wiener".
However, after briefly consulting a few sources, I thought it might be a good idea to introduce my readership to the argonaut itself, as opposed to merely its PHABULOUS PHALLUS. When we think of cephalopods (which I hope you do several times per day), most people think of octopus and squid, possibly cuttlefish too if they had the misfortune to spend time with me around age six or so. And while the argonaut is certainly an octopus (it belongs to Order Octopoda) it's a weird octopus and not usually what people envision when they hear the word. An image will explain what I'm talking about:
As you can see, she's riding around in one of the many things that makes argonauts so distinctive, as well as being the source of their nickname, the "paper nautilus": the thin calcium carbonate eggcase of the female.
They are not nautiluses, nautiluses belong to an entirely different order (Nautilida, to the shock of nobody) and their shells are quite different than those of the argonaut. The government of Australia has even prepared a handy and user-friendly argonaut vs. nautilus comparison chart so that you'll have the resources you need when push comes to shove in those high-stakes cephalopod knowledge duels.
ALSO NOTE: In looking for information for this post I've seen many posts that say that they are "closely related to octopuses". This is not actually true, given they ARE IN FACT octopuses. Octopoda is a very diverse order that I intend to post more about in the future because I am mildly obsessed with cephalopods in case you missed the note; argonauts are not the strangest of the order. Wait until we get to some of the more obscure orders under Cephalopoda, like Sepiolida, or even hang out with more extinct cephalopods!
The shell/eggcase of the argonaut is created from secretions produced by two of their dorsal arms, which are webbed and feature chromatophores, aka the things that lets cephalopods change colors real good. Let's have some VISUAL AIDS:
S. G. Goodrich Animal Kingdom Illustrated Vol 2 (New York: Derby & Jackson, 1859)2:495
Big ol' webbed arms. Arms != tentacles, by the way. And sans shell!
The shiny pink part of the shell are the webbed arms, all splayed out.
These modified arms are particular to the females; the males have their own...modified arm, but that'll come later. For now, more SCIENCE FACTS ABOUT ARGONAUTS:
-Females can leave and re-enter their shell because they cling to it with their suckers. This is not the case for nautiluses, who are physically attached to their shells.
-Argonauts do not in fact use their webbed arms as sails by sticking them above the water, although this was apparently a widely-accepted belief back in the day. You can thank Aristotle for that one, by the way. While I can't confirm it through experience, supposedly they also exhibit this ability in Jules Verne's 20,000 Leagues Under the Sea.
-Oddly, argonaut shells are not an example of a remnant cephalopod shell, evolutionarily speaking (the vestiges of this shell can be seen in the cuttlebone and the gladius/pen of the squid). The jury is still out on how the argonaut acquired this ability in terms of evolutionary biology, but what we do know is that the true mollusk shell is formed through an internal shell sac; the argonaut's shell is formed through an entirely different external mechanism, indicating that despite some visual similarities, their magnificent eggcase chariots are evolutionary innovations.
-Continuing on about the shell, most true cephalopod shells are composed of aragonite; the shell of the argonaut is composed of calcite.
-This is probably assumed at this point, but argonauts lay their eggs in their eggcase; most octopuses lay their eggs in strings inside of caves.
-BIG difference between most octopus and argonauts: octopus are benthic, argonauts are pelagic. Basically, most octopus hang around on the sea floor at varying depths. Sure, they swim around some, but by and large they live on the floor. Argonauts, on the other hand, live in the open ocean, relatively near to the surface.
This also means that they are much more difficult to study because of the sheer lack of availability. Contrast this with this octopus wandering between tide pools like it ain't no thang. There will occasionally be mass strandings, which shell collectors often enjoy. Like many other cephalopods they keep poorly in captivity, which doesn't really help the situation.
-The word for argonaut in Japanese is "蛸船" (takobune）, which literally means "octopus boat". This is an absurdly cute name.
Now let's talk about ARGONAUT SEX. Argonauts exhibit significant sexual dimorphism, i.e. females are WAY bigger than the males; males' full growth is about 10% of that of the female of the species. Males also have the star of this entry, the detachable female-mantle-cavity-seeking hectocotylus. Unfortunately for male argonauts, they only get to mate once. I could write all this out, but I'd rather quote (bolded emphasis added by me):
The male argonaut has a modified third left arm that carries and stores sperm. This arm develops in a pouch under the male’s eye until needed for fertilization, at which point it explodes out of its sheath and leaves the body (Nesis, 1977; Iliffe, 1982). The arm attaches to the outside of the female’s mantle via suckers, then autonomously wiggles into the mantle cavity (Nesis, 1977). Originally, this arm was thought to be a parasitic worm and was given the scientific name Hectocotylus, and the modified arm is still called a hectocotylis in octopuses and squids. The detached arm is free-swimming and very active, but it probably cannot seek out females since it lacks a sense of direction (Iliffe, 1982). Upon expulsion of the hectocotylus, the male dies, and the arm, with its threadlike organ to carry and store spermatophores, remains in the female’s mantle cavity until such time as she chooses to fertilize it (Iliffe, 1982; Norman, 2003).
Female argonauts can have a few hectocotyluses within their mantle cavities simultaneously and often lay eggs after attaining spermatophores (Norman, 2003).
Orenstein, M., & Wood, J.B. (2007). Argonauta argo, argonaut. Retrieved from http://www.thecephalopodpage.org/MarineInvertebrateZoology/Argonautaargo.html
Crudely summarized, the male argonaut's terrifying micro-penis EXPLODES out from under his eye, he dies, penis-arm swims to the female and plops itself into her mantle cavity minus the male who is now just another tiny seven-armed carcass drifting in the sea. Note that females can:
a) carry a number of sperm packets simultaneously
b) tote the sperm packets around until they decide to fertilize their eggs.
I don't know if argonauts have this ability, but I know some organisms who do the sperm packet thing (cuttlefish, if I'm not mistaken) can decide which sperm packets they want to use.
As mentioned earlier, people most frequently encounter argonauts in as either washed up and dead or just the eggcase alone. However, occasionally live ones will be encountered on the beach, as demonstrated in this video:
Note how she's jetting water pretty much the whole time and expels ink at 2:26. At about the same time she wraps her webbed arms around the eggcase, whereas she had them tucked in before. Hopefully she made it back safely.
REGARDING EGGCASES
The Argonaut shell is formed, curiously enough, by the females only; as among more highly organized beings sometimes, the gentler sex outshine their brothers in the splendor of their apparel, and the extent it occupies. Unlike many, however, the Argonaut toils not, neither does she spin. Folding her arms about her, in her earliest infancy, she is speedily arrayed in all her glory, and has not shown any discontent at the old fashions since the time of Aristotle.
(Hall, 1869)
I desperately wish that this was how scholarly papers were still written, full of whimsy and random opinions regarding cephalopod aesthetics. This is why I am quoting resources about argonauts from the 1860s. /TANGENT
I've spent most of this entry talking about the organism itself; however, most people are more interested in the delicate eggcases of the argonaut than the octopus that travels in it. Argonaut species can differentiated by the types of eggcases they produce. A gallery of eggcases for sale can be seen here; Wikipedia has a handy comparative chart as well:
Of course, I'm more interested in the octopus than the shells really, so here's one without her shell. You can see her webbed arm trailing out behind her:
I will leave you with a video of an argonaut in captivity that shows off the chromatophores (color-changing cells) beautifully. Like most cephalopods in captivity, it is not doing anything particularly exciting, but it's still lovely to observe:
*=BONUS! Here's am oddly beautiful video of leopard slugs mating. It gets hot and heavy at around 1:30.
BONUS BONUS! Here's the opposite of the above video, a banana slug chewing off its partner's penis! You should read the whole page, it's fascinating. Apparently the researcher observed a banana slug suffering from priapism (i.e. penis won't go down) and it decided to take matters into its own metaphorical hands by chewing its ownpenis off of its head (that's apparently where they keep their junk). TOO HOT FOR TV XXX MEGA-HUNG SLUG PENIS PIX AT 3:00
