Big questions often come from little people and there are so many times that I have been asked by children why I reference the limbs of an octopus as “arms” and not “tentacles”.
Here’s why: Arms have suckers down the full length of the appendage. Tentacles only have suckers near the tip. Thereby, all eight octopus appendages are arms while squid have two tentacles and eight arms. Further, the purpose of tentacles is generally limited to feeding where arms have more functions. Octopuses use their limbs for feeding, locomotion, reproduction (if male*), defence, etc!
Oh and why are they called “arms” vs. “legs”? Because octopuses’ appendages have more purposes than just locomotion.
Octopus walking on her arms (and you thought YOU were special 😁). How to know this is a female octopus? See below for the link to my blog* on octopus sex.
There are scientists who have put forward that some octopus species use two of the limbs mostly for locomotion whereby they would have two “legs” and six “arms” but let’s avoid that debate!
While we are on the topic of semantics and cephalopods, and anticipating that there will be those who question my use of the plural form of “octopus”, please note the origin of the word octopus is Greek, not Latin. Thereby “octopuses” or “octopods” is truly more correct than “octopi”. From a strict linguistic perspective, the most correct is “octopods” but I choose not to use that. I think if I were to say “octopods” it would distract what I am trying to communicate that is more important that grammar. I might also come across as pretentious and have fewer human friends 🐙.
There, don’t you feel much better armed to speak for our awe-inspiring eight-legged neighbours? Or, are you up in arms?
A female Giant Pacific Octopus hunting . . . photos brought to the surface for you on April 4, 2021.
This individual lives north of Port Hardy, in Browning Pass.
She’s a giant among other giants.
The Giant Plumose Anemones stand tall above her, at up to 1 metre in height.
Her arms feel between the rocks to flush out prey, her mind processing all she detects from her eight limbs, her vision, and the further stimuli upon her skin.
A China Rockfish is hovering nearby, likely often accompanying her when she is hunting to benefit from what prey emerges when touched by her arms.
Her colours change, flashing white at times. Then, again camouflaged among the boulders covered with the pink of coralline algae species, and studded with Orange Cup Corals and the plumes of feeding tentacles of Orange Sea Cucumbers.
Two humans are in awe at chancing upon her and being able to hover, navigating the space between not wanting to disturb and also wanting to amplify the wonder above the surface, hoping it somehow contributes to being better humans.
We’re aware too that we are limited by how much air remains in our tanks; the nitrogen building in our blood; and the cold creeping in through our dry suits (despite the adrenaline surge of watching her).
But she, she is limitless here.
She is perfection.
This image provides a clue about her gender. See information near end of the blog. Please note that photos are cropped. Our presence was certainly not undetected but wanted to minimize disturbance. The China Rockfish that was following her as she hunted. Her eyes are closed (likely due to the annoying light coming from me) but she can still detect light. Read below.
Octopus Gender:
I know this was a female because the third arm on the right does not have a “hectocotylus”. Male octopuses have a specialized arm with no suckers at the tip called the “hectocotylus arm” by which they hand off spermatophores to the female. In Giant Pacific Octopuses, the hectocotylus arm is the third on the right. See more in my recent blog “Giant Pacific Octopuses, How Do They Mate?” at this link.
Octopus Vision:
You can see that the pupil’s shape is very different from ours. Their retina is very different too.
Octopuses and other cephalopods have only one kind of photoreceptor cell while we have rod cells and three types of cone cells allowing us to see in colour. So how can cephalopods discern colour when they have only one kind of light receptor in their eyes? And they must be able to discern differences in colour. Consider how they signal with colour and how they camouflage.
Research from 2016 puts forward that their uniquely shaped pupils act like prisms, scattering light into different wavelengths (chromatic aberration), rather than focussing the light into a beam onto the retina. The hypothesis, tested with computer modelling, is that cephalopods can then focus the different wavelengths onto their retina separately by changing the distance between the lens and the retina, thereby separating the stimuli and discerning colour. Note that the sharpness of their vision is believed to be different for different wavelengths / colours.
Even with their eyes closed, octopuses can detect light with their skin. This is tied to their ability to camouflage with the photoreceptors in their skin responding to specific wavelengths of light (different wavelengths = different colours).
Note too that octopuses do not have eyelids. They have have a ring-shaped muscular fold of skin around the eye that closes in the way of an eyelid (especially when some annoying human is taking photos).
More Octopuses Hunting
Here’s the link to another experience where we saw a Giant Pacific Octopus hunting AND interacting with a Wolf-Eel (includes video).
Following on the success of my blog answering the important life question: “How do octopuses poo?“, it’s high time I address “How do octopuses mate?”
Why? Because truly, by having better understanding of the adaptations of species that look so different from us, I believe we can be better humans.
What has catalyzed this blog finally being written is the following video by fellow diver Mel Vincent with buddy Jerry Berry. On a night dive, what they thought was one Giant Pacific Octopus, turned out to be two AND evidence that they had likely mated. The evidence is the empty “spermatophores”.
Spermatophores? The name gives you a good sense of what those might be, they are the rope-like sperm packets of a male octopus.
This is most likely the female although in neither can the 3rd arm on the right be seen to confirm if there is a hectocotylus arm or not. Giant Pacific Octopuses are Enteroctopus dofleini, the largest octopus species in the world.
Male octopuses have a specialized arm with no suckers at the tip called the “hectocotylus arm”. In Giant Pacific Octopuses, the hectocotylus arm is the third on the right. The section at the top which has the spermatophores is called the “ligula”. This section does not have the cells that allows colour and texture to change (the chromatophores). So the males often keep it curled up which helps discern males and females i.e. look for a curled up arm.
The spermatophores are made inside the male and the male grabs them by passing the hectocotylus arm into his body through the siphon when it is go time. It’s not a fast process. Apparently it takes about an hour for the sperm to move to the top end of the spermatophore. The spermatophores pass down a grove in that arm helped by cilia. Ultimately the spermatophores are ejected by the ligula and the shape of the spermatophore (and swelling inside the female), lock it in place in the female.
Where to “deliver” the contribution to the next generation in a female octopus? Through her siphon, to her oviduct(s). The swollen end of the spermatophore then bursts and the female stores the sperm in her “sperm receptacle” till ready to fertilize and then lay her eggs. Reportedly, about 40 days after copulation (delivery of the spermatophores) the female attaches up to ~68,000 fertilized eggs to the top of the den she has chosen . . . to be her last.
Credit: Pierangelo Pirak Source: BBC article on octopus sex
In Giant Pacific Octopuses, a spermatophore can apparently be up to 1 meter long and contain over four billion sperm. Usually two spermatophores are involved in one copulation. Such large numbers of sperm, and eggs, are needed when your babies hatch into the soup of the ocean. But mother gives them a fighting chance. Read on!
The spent spermatophores apparently may hang from the female for a while so can it be known for sure that the two Giant Pacific Octopuses Mel documented had just mated, or mated at all? It can’t be known definitively but with there being two octopuses, and that they had been interacting, it does suggest that mating had occurred. It certainly is extraordinary to have chanced upon the spermatophores of wild Giant Pacific Octopuses.
When a female giant Pacific Octopus is ready to mate, it appears that she selects a den and attracts males to her. There is no conclusive evidence on how the female entices males, but there are strong indications that she produces some sort of chemical attractant. There are several reasons for believing this to be true.
The first reason is that giant Pacific octopuses are ordinarily solitary, and a smaller female would normally avoid a larger male that might attack and eat her. Jim has seen as many as nine males, however, in the immediate proximity of a female in a den. The males were scattered around the den and appeared to be unaware of each other, as there were no interactions amongst them. This was most unusual.
The second reason is that Jim has observed and seen video of large males standing atop prominent rocks. The octopus faces into the current and spreads out his arms like an open umbrella, turning slowly back and forth as the current flows past. We know that octopus suckers are sensitive chemical sensors, so it’s likely that the male tastes the water flowing past. His slow turning may enable him to identify the direction of the female’s attractant.
How the female selects a male—and whether she mates with one or more than one male -are still unknown. Jim is currently working with a genetics professor at the University of Victoria to try to resolve these questions.
Once a female selects a male, there are several ways in which the male transfers sperm to her. Sometimes the male mounts the female, almost completely covering her. In other cases the male merely extends his hectocotylized third right arm into the fe male’s den. Although the actual transfer of sperm requires only two to four hours, the mating process can last several days, so divers have a considerable handicap when trying to observe such behaviour. Indeed it is a rare event to witness a mating pair, and Jim has only seen nine matings. This is one situation in which observations in an aquarium are far easier than those in the open ocean. An aquarium researcher can set up a video camera and organize teams to watch the process on a 24-hour schedule until the event ends.
Jim, along with three other researchers, has combined experiences from open ocean and aquarium observations to produce a publication about giant Pacific Octopus matings. The study revealed that the male and female mate for approximately four hours and that repeat matings have been observed. In aquariums there is usually only one male in the tank with the female, so questions about multiple males and how the female selects a particular mate remain unanswered.
The male passes the female an elongated package of sperm called a spermatophore, which may be up to one metre (three feet) long, which he deposits in one of the female’s two oviducts. It is believed that when mating the male actually places two spermatophores in the female, one at the entrance to each oviduct. At this time the female is not yet pregnant—the term really does not apply to invertebrates anyway—but she has stored the sperm and will head off to find a suitable den to lay her eggs. The male, if he still has unused spermatophores, may try to find another female.
Thę den the female selects is usually deeper than 20 m (66 ft). Jim has noted that dens where previous females have nested were reused 41 percent of the time. These preferred dens tend to be under large flat rocks that provide a suitable overhead surface for the female to attach her eggs.
Once the female selects the den, she sometimes fortifies it by gathering rocks from the surrounding area and dragging them to the den. She often piles them up to create a wall of boulders that keeps out predators. A few days to a month may elapse between mating and selecting and preparing a den.
LAYING THE EGGS
Now the female begins to lay her eggs. She turns upside down and clings to the roof of the den while she lays the tiny eggs one at a time. Each egg is produced in the ovary and coated with rich yolk to provide energy for the developing embryo. At this point some sperm is used to fertilize the egg, and it is coated with a material that hardens into a rubbery, semi-opaque shell. Each egg is extruded individually through the funnel and grasped by the small suckers that surround the mother’s mouth.
The body of the egg is a mere six millimetres (0.2 in) long about the size of a grain of rice—with a slender tail that adds another 11 mm (0.4 in), making the total length of the egg about 17 mm (0.7 in). The mother’s small suckers deftly manipulate the tail of the egg along with the fails of other eggs and weave them together into a slender string. She produces a secretion and applies it to the tails to bind them together. Over a period of three or four hours, while hanging upside down, the female produces a string containing an average of 176 eggs. Having glued this string to the roof of the den, the female descends to rest before returning to lay another string.
Eventually, over 28 to 42 days, the female will produce a complete nest of about 390 strings with approximately 68,000 eggs.
Once the female has finished laying, she spends the next 6.5 to 11 months tending the eggs. She grooms them with her suckers to ķeep them free of bacteria and other organisms that might damage them. Usually she is not completely successful, as often some eggs are encrusted by colonial animals called hydroids and do not hatch.
The female blows water through the strings of eggs with enough force that they jostle around. This helps keep them clean and free of growth and will be critical when the eggs start to hatch. She also protects the nest against predators such as sea stars, not always successfully. Mottled sea stars (Evasterias troschelii) have been observed robbing egg strings from a den.
Video above by Laura James of a mother Giant Pacific Octopus tending her eggs.
Other creatures enter the nest but do not appear to do any damage. These include small worms, snails and crabs such as the longhorn decorator crab (Chorilia longipes) and the sharpnose crab (Scyra acutifrons).
While the female tends her eggs, she does not feed. We don’t know the exact reason for this, but one suggestion is that if the female left the den to hunt, she would leave the eggs unat tended and vulnerable to predators. Another suggestion is that the presence of food scraps in or near the den might attract predators. Jim does not subscribe to either of these theories. Because this behaviour is common to many cephalopods, he believes it is more likely linked to an ancestral trait, the reason for which may no longer exist. This is an example of innate behaviour, part of the hard-wired information an octopus is, born with.
The development of the embryos depends on the surrounding water temperature. The colder the water, the slower the develop ment; the warmer the water, the faster it proceeds. This is true among most egg-laying marine invertebrates.
Jim has been able to observe much of the development in the wild and develop a time frame for estimating when hatching would occur. If he was lucky enough to have witnessed the egg laying, he would have a pretty accurate idea of how the eggs would look as they developed. In most cases he did not see the egg laying, however, and would have to observe the eggs for signs of development to predict when they would hatch.
WATCHING THE EGGS: A DIVER’S VIEW
Newly laid eggs are glossy white and look like white raindrops. The core that the eggs are woven into is pale green, but within a few weeks the core turns black and remains so.
Two small red dots appear on each egg about 120 to 150 days after the eggs are laid. These dots, the developing eyes of the embryo, are visible through the egg shell. The eggs are no longer as shiny white, and soon one can see the brighter yolk sac in the large end of the egg and the darker developing embryo at the small end.
About 180 to 210 days after the eggs are laid, the embryo has used up much of the yolk, and the size of the yolk sac has de creased while the size of the embryo has increased. So that the embryo can continue growing, it moves into the larger portion of the egg. This is actually the second reversal, but it is the only one that a diver can observe.
Over the next few months a diver can watch as the yolk sac becomes smaller and the eggs become darker. Those with sharp eyes may be able to see the movement of the embryo within the egg and the flashing of brown and white colours as the embryo tries out its chromatophores.
About 240 to 270 days after the eggs are laid, hatching occurs.
It might seem logical that the eggs would hatch over the same period of time and in the same order as they were laid. This does happen in many octopuses, including the giant Pacific octopus, but not always. Jim has witnessed a number of hatchings in which he has seen the nest intact one day and completely hatched out the next morning.
Jim collected strings of unhatched eggs from time to time and took them to his lab. When observing the eggs through a dissect ing microscope, he found that the water surrounding the eggs was warmed by the microscope lights, often causing the eggs to hatch. He probably collected strings of eggs that had not been laid at the same time, yet even eggs from different strings hatched nearly simultaneously.
Some type of chemical released from a hatched egg stimulates other eggs to hatch as well, Jim suspected. The embryos often had different amounts of food remaining in the yolk sac below their mouth. In some cases the yolk sac was consumed, but in others the yolk sac was still large enough that the paralarva had to bite it off. Clearly some of the paralarvae were not as well developed as others but were able to survive even if they hatched somewhat prematurely.
The hatch normally occurs at night. It may start at dusk, but often it is several hours after dark before things really get under way. As the eggs hatch in ever-increasing numbers, the female blows strongly onto the strings of eggs, causing them to thrash around. This helps the paralarvae to pop out of the eggs and aids in flushing them away from the den.
MOTHER’S JOB IS DONE
In most cases the female survives the hatching and lingers in the den for another few weeks before she dies. During the entire nesting period, which may have dragged on as long as 11 months, the female has not eaten. By hatching time she has lost more than 60 percent of her body weight, sometimes as much as 85 percent! Even though the eggs have hatched the female continues to “mother” them as before. She grooms the hatched-out egg cases even though the paralarvae are long gone.
Experiments have been done in which the eggs have been re moved from the ovary of a mated female. Incredibly the female went through the entire egg laying and grooming process, even though she had no eggs or nest. This “phantom nesting” shows that a behavioural lock and key is triggered at sexual maturity or at mating.
In some cases the female does not have enough energy stored to survive the whole nesting period and dies before the eggs hatch. Usually her last act is to vacate the den and crawl away. She usually only moves a metre or two before she dies. Again there is no solid evidence on why the female va cates the den, but Jim sub scribes to the theory that if the female died in the den her de composing body could foul the water and attract scavengers.. One can understand that fe males not leaving the den might have resulted, in an evolution ary sense, in the nest being dis covered and eaten. This would result in the failure of her genes to be passed on to successive generations. The genes that were passed on would be those of females who successfully distracted predators away from the nest.
While this strategy is interesting, it is not totally successful. In several cases where the female died before the eggs hatched, even though the embryos developed properly, the eggs did not hatch. Without the agitation provided by the female blowing wa ter over them, the closely packed eggs remain immobile and pressed against each other. As a result the paralarvae are unable to force their way out of the eggs, and most perish.
Jim found it sad to observe nests where only a partial hatch was successful. As he counted strings and eggs, he often found thousands of dead paralarvae. Sometimes nature seemed harsh and wasteful.”
Video below by Laura James of Giant Pacific Octopuses hatching and mother dying.
Male anatomy on left and female on right. Source: Hanlon, R., & Messenger, J. (2018). Reproductive Behaviour. In Cephalopod Behaviour (pp. 148-205). Cambridge: Cambridge University Press. doi:10.1017/9780511843600.008
Further detail on mating in Giant Pacific Octopuses from “A Snail’s Odyssey”
“After a short courtship, the male Enteroctopus dolfleini grabs the thin or distal end of a spermatophore from its penis using the groove in its hectocotylus arm and thrusts it into the orifice of one of the female’s oviducts. This initiates a complex series of events within the spermatophore that cause the sperm rope to be pushed into the thin or distal end, which swells to accommodate the incoming load of sperm and leads to evagination of the ejaculatory apparatus (see illustration on Left). This action locks the sperm-filled swelling in place within the oviduct and prevents it from dropping out of the female. The sperm rope is moved along by pressure from seawater diffusing into the proximal end of the spermatophore and from elastic contraction of the sperm rope itself.The movement takes about an hour. These actions haul the entire mass of tightly encapsulated spermatozoa over a distance of a meter from the proximal to distal end of the spermatophore. The sperm are now positioned in a swollen bladder or reservoir located at what was previously the thin or distal end of the spermatophore (see photograph on Right). The next step, evagination of the ejaculatory apparatus, occurs suddenly and produces a crink in the tube that locks it in place in the oviduct. The locking-in may additionally ensure that spermatozoa are not lost in “back-flow” from the oviduct. The swollen end of the spermatophore now bursts and the sperm are moved into the female’s sperm receptacle for later use. The process is repeated with a second spermatophore. About 2-3h after the arm is first inserted and after repeated pokings, the female has two empty spermatophores hanging from its oviducal orifices.”
It happened when we placed a memorial for a dear departed friend, Markus Kronwitter.
My primary reason for sharing this is for Markus’ family and friends but, I think others will find something here too.
You see, a Giant Pacific Octopus attended and sat right atop the memorial.
Let me recount using photos.
Memorial made by Stephanie Lacasse.
Markus owned and operated North Island Diving in Port Hardy. He was a dear friend and incredibly important to our dive club, the Top Island Econauts. He died more than 3 years ago and the memorial today was to honour him and maybe offer some comfort to his wife Cecelia and his two daughters, Rosie and Jennifer.
The location was Five Fathom Rock just outside Port Hardy. Part of Markus’ legacy is that he fought for this rocky reef to be recognized as a Rockfish Conservation Area. (More about the significance of that in my eulogy at the end of this blog).
After we shared thoughts about Markus at the surface, down we went to the highest point of the reef. We would wait there till the memorial was carefully descended by Steve Lacasse of Sun Fun Divers using a lift bag and rope.
We wanted to position the memorial there, near a sunken metal beer keg. The keg used to be a mooring float on this site. It was put there by Markus but, by mysterious means, had sunk to the bottom.
As soon as we got to where the memorial was to be placed, I saw a Giant Pacific Octopus, fully out in the open.
You can even see the beer keg right in the background.
After about 5 minutes, he retreated partially into his den, likely because of some annoying underwater photographer with flashing lights.
Note that I do know this was a male Giant Pacific Octopus because the third arm on the right was a “hectocotylus arm”. Only males have the hectocotylus which stores sperm. More on that at this link. (This individual also had an injured arm. It was only about half length but will regrow. Yes, some of the awe that is octopuses, is that they can regenerate limbs.
Giant Pacific Octopus in his den.
But then . . . when Steve arrived with the memorial, the Giant Pacific Octopus darted out of his den, landed right atop the memorial and started flashing white. See the memorial under the octopus in the photos below?
Steve Lacasse with the octopus on the memorial which was still attached to the rope and lift bag.
You can imagine how we marvelled as this unfolded and that some pretty big emotions were felt.
Eventually, the Giant Pacific Octopus moved away. Then, the memorial could be positioned as we had intended, but not before a mature male Wolf-Eel also went swimming by.
There’s no photo of that I am afraid. I was a little overwhelmed.
Memorial positioned.
Dive club members from left to right: Dwayne Rudy, Steve Lacasse, Natasha Dickinson, Gord Jenkins and Andy Hanke.
Somewhat dizzied by emotion, we continued with the dive.
Below, I include some photos of what we saw, especially to give Markus’ loved ones a sense of what this site is like and what he fought for.
Mature male Wolf-Eel in his den, very near the memorial.
One of 100s of Black Rockfish at this site (and a Mottled Star).
Male Lingcod guarding an egg mass with 100s of eggs.
Male Ling Cod. The boulders here give an indication of why this is such ideal fish habitat. There are so many crevices to hide in and rocks to lounge upon.
Rose Anemones aka Fish-Eating Telias. Sun shining down from the surface, five fathoms above us.
Tiger Rockfish – longevity can be 116 years WHEN given a chance.
See the male Lingcod under the huge mass of eggs? He’s got a lot to protect!
And then . . . just as we were about to ascend, there he was again – the same Giant Pacific Octopus.
The Giant Pacific Octopus with dive buddy, Natasha Dickinson.
How I wish we could have stayed longer. We had to surface to a far less mysterious world, but with hearts full and so much to tell Cecelia, Jenny and Rosie.
Goodbye Markus.
We’ll be visiting again soon.
Image below is of the memorial 20 months later, October 2020. It has become part of the seascape and it appears a China Rockfish is living very near.
My Eulogy for Markus.
It’s my great honour to say a few words before we dive on Five Fathom Rock to position Markus’ memorial.
I of course found it excruciating to try to find the words fitting of Markus, because you have to tap into the emotion to find the words.
It’s been more than 3 years since Markus died. Cecelia, Jenny and Rosie you need the words and, even more, you need this place where your thoughts and feelings can be anchored.
In trying to find the words, I dared remember what it felt like to be around Markus. I don’t think that I know anyone else who was quite like him in knowing the right thing to do, no matter how hard it would be and no matter how many injustices he had suffered.
Markus was about making things better and standing up for what was right. He was a man of truth and science. He appeared unflinching in facing reality. He did not suffer fools. He saw through people with crystalline clarity. He walked his own path – in red “holely soles” and multi-coloured pants – and had the wisdom to stop to have Cecelia join to walk beside him.
He made hard decisions.
He . . . was . . . a . . . fighter.
He fought to be here on northern Vancouver Island.
He fought for his girls.
He fought for our dive club.
He fought for the fishes, now flourishing beneath us.
He fought for his life.
[When diagnosed with cancer, he was told he had 2 years to live. He lived for 14 years post diagnosis].
And he has left an extraordinary legacy.
Part of this, is the legacy of Five Fathom Rock.
Markus fought for this to be a Rockfish Conservation Area so that the fish that live here might get a chance to grow bigger, reproduce more, and to thrive.
And there’s success. It’s so beautiful down there Rosie, Jenny and Cecelia. The fishes are thriving – there are clouds of rockfish and it’s so powerful to think that some, like the Tiger Rockfish, might get a chance to live to be more than 100-years-old.
If there were any place where I could picture Markus, it would be here darting around with yellow fins, fish-like himself. Clearly so at home . . . here.
His efforts for Five Fathom included trying to have a mooring here and his creativity was to use a big metal beer keg. It’s down there now, on the highest part of the reef , close to where there are 2 Wolf-Eels. It’s where we’ll attach the memorial.
And how perfect that this will happen at a time when the Lingcod fathers are protecting the next generation, standing guard, not suffering fools, making very clear when you’re trying to get too close without good intent. Fiercely fighting for the next generation, with an extraordinary sense of place.
He loved it here.
It’s impossible to forget him here.
Not that there is any possibility of forgetting Markus or what he stood for.
His legacy of course includes you Rosie, Jenny and Cecelia. He loved you so much and I can’t even imagine how hard he fought wanting to be here still to protect you, to make sure you would always be okay.
Jennifer and Rosie, you are fighters like your Papa Markus.
Jenny – I also think you have his sense of purpose.
Rosie – I think you have his sense of place.
Cecelia – the love in your eyes makes clear how you carry Markus with you always.
Markus Kronwitter. It is here on Northern Vancouver Island that he found his wild. It is with you three, that he found love.
It’s one of the characteristics that unifies every living thing on the planet – we all need to get rid of waste.
How do octopuses do it? See the video and explanation below.
Why share? Because I solidly believe the world can be a better place through understanding and respecting the commonalities and differences of others AND through marvelling at the natural world.
“The first structure for food gathering [in octopuses] is the interbrachial web, the umbrella-like membrane between the arms that the octopus used to enfold food such as crabs, shrimps and sometimes even fishes and birds.The web forms a bag-like container that holds prey close the the mouth . . .
The second structure is the mouth. An octopus has two pair of salivary glads, anterior (front) and posterior (rear). The posterior salivary glans produce a toxin called cephalotoxin. in giant Pacific octopuses this is not known to be deadly to humans, whereas in the blue-ringed octopus of the South Pacific it has killed people. When an octopus captures food in its web, it secretes cephalotoxin into the water, where it is absorbed through the gills of its prey. The neurotoxin affects the nervous system and causes the prey to lose consciousness and stop struggling. The octopus can then use its suckers to aid in dismembering prey such as crab.
The beak, the hardest part of the octopus, is made of the same chitonous material as human fingernails. It is black and looks like the beak of a parrot. The mouth also has a specialized tongue called a radula. The file-like organ is covered with tiny, sharp teeth that are replaced when they wear down, much as sharks regrow teeth. The radular teeth shred the prey’s tissue once the beak has bitten the food into chunks. Working together with the beak and radula are secretions of the anterior (front) salivary gland. The gland produces a mixture of substances called enzymes, which cause the food to break down quickly into a jelly-like substance that can be easily digested. A combination of the enzymes and the radula enables an octopus to remove even the tiniest bit of tissue out of the tip of a crab’s leg.
Giant Pacific Octopus beak. It’s made of keratin.
Once the food is captured, eaten and swallowed, it travels along a short tube called the esophagus (similar to the throat in a human) to a structure called the crop. This is not exactly the same as a bird’s crop, but it does function as a storage place for undigested food.
If the stomach is empty, food passed immediately from the crop to the stomach, which despite distinct differences, functions much like our stomach. In the giant Pacific octopus the digestive enzymes do not come from the wall of the stomach but are produced by the liver and introduced into the stomach through ducts. These enzymes cause the food to break down into small molecules that the blood absorbs and transports back to the liver. There they are processed and distributed to the cells of the body. This dual-function liver is different from a human’s whose liver primarily deals with the products of digested food.
Summary of octopus digestion. Source: Super Suckers by James Cosgrove and Neil McDaniel Harbour Publishing. Illustration by Adrienne Atkins.
Now we find another major difference from vertebrates such as humans and also from squids. Once the food in the octopus stomach is digested, the waste material has to be evacuated. The octopus stomach, however, has only a single tube leading in and out. This means that the waste material must be evacuated through the same tube the food entered before more food can be introduced for digestion. You might call this the “digestion on the instalment plan.” The waste comes out of the stomach into the intestine, which encapsulates it and moves it along till it eventually reaches the end of the intestine located at the entrance to the funnel [aka siphon]. Octopus poop, ejected from the funnel, looks a bit like a slender . . . ribbon . . . .
In giant Pacific octopuses the processing of food, depending on what is being eaten, can take many hours. On average these octopuses make six hunting trips a day, reposing in their den most of the time while they process food.”
Below, video of a giant Pacific octopus hunting. In this encounter, the octopus passes directly over a mature male Wolf-Eel in his den. THEN, a Decorator Warbonnet emerges as well.
Diagram below names addition octopus anatomy.
Further octopus anatomy. Source: Super Suckers by James Cosgrove and Neil McDaniel Harbour Publishing. Illustration by Adrienne Atkins.
Defecation by Pearl the Giant Pacific Octopus at the Sitka Science Marine Science Center. Her diet has a lot of shrimp and crab in it and likely accounts for the colour of the faeces.
It’s Canadian Thanksgiving and World Octopus Day (OCTOber 8th = get it?).
There’s so much to be grateful for. The health and freedom that allows me to live this life of depth; the love and support of buddies, family and community; AND the lessons learned, ESPECIALLY from octopuses.
What essential life lessons have I learned from them?
Do not fear what may look foreign;
Respect alternative intelligences;
If necessary, blend in to escape detection;
When you know what you want, hold on tight;
Trust in your ability to squeeze through tight spaces and come out okay on the other side;
Ink out the negative in your life and jet away, leaving it behind you;
Know your home and keep the garbage outside; and
Be big-hearted (octopuses have three), guard the next generation, and use your beak when needed!
And thankful for YOU that you care enough to read this blog and help make my efforts feel so worthwhile. I’ll stay at it till I am an octogenarian (and beyond).
It is one of the most remarkable encounters I have witnessed in all my dives.
It’s a fortunate enough thing to be able to watch a large Giant Pacific Octopus when it is hunting. In this encounter, the octopus passes directly over a mature male Wolf-Eel in his den. THEN, a Decorator Warbonnet emerges as well.
It was an exciting day in this wonderful marine neighbourhood.
I hope this 3-minute clip allows you to share in the awe and excitement.
For me, this was the NE Pacific Ocean equivalent of seeing a giraffe, elephant and rhino in close proximity.
Video and photos contributed by dive buddies Katie Morgan and Diane Reid while on our trip with God’s Pocket Dive Resort.
For more information on Wolf-Eels (including that they are not an eel at all), see my previous blog here.
For more information on Giant Pacific Octopuses, click here for previous blogs and here for a blog specifically on hunting in Giant Pacific Octopus.
Please note, I have shared our experience below to reduce the misunderstanding and demonization of octopuses NOT to stimulate diver attempts at interactions. What is described below was an unsolicited gift experienced by those with a very high level of dive experience; knowledge of octopuses (and dive buddy) behaviour; and solid safety protocols.
The Kraken?! Devilfish?!
Scary?! Dangerous?! Alien?
Suggest such things about a Giant Pacific Octopus to any scuba diver respectful of marine life who has had an encounter with one of these gentle giants, and there is going to be a very strong response shattering such mythology.
As it always goes, fear and mythology thrive where there is absence of knowledge.
Any negative encounters between divers and Giant Pacific Octopuses that I am aware of, result from divers manhandling them “insisting” on an encounter, or involve octopuses that are habituated as a result of being fed by humans.
We, as divers, are so fortunate to come across Giant Pacific Octopuses in their world where they are invertebrate royalty. We are able to meet them on their turf, and thereby know how inquisitive and intelligent they are. We know they are mighty, highly adaptable predators.
And, we know too, when we look into their eyes, that observation and assessment is being reciprocated.
That preamble was necessary before sharing what happened today.
I had been taking photographs of Lingcod males guarding their egg masses and noted that my dive buddy Natasha Dickinson was signalling me with her light, indicating that she had found something of particular interest.
I took a few more shots and then swam towards her and found . . . my dive buddy with a Giant Pacific Octopus completely covering her face. Sorry that I missed that shot. I was so in awe of what I saw.
Natasha is an incredibly skilled and experienced diver with a deep respect for marine life. She was clearly not afraid, nor was the octopus.
Natasha had taken the precaution of putting her hand over the regulator in her mouth in case the octopus took an interest in that but otherwise, allowed her to explore.
I would learn later that, while waiting for me she had been watching the Copper Rockfish that you will see in all but one of the photos in this blog. This rockfish stuck very near the octopus. A buddy? That I don’t know but escorting a Giant Pacific Octopus on the hunt is a really good strategy. As the octopus flushes out animals from under rocks with his/her arms, the rockfish can grab the prey that do not end up under the octopus’ mantle.
While observing the rockfish, the Giant Pacific Octopus had slowly advanced toward Natasha and she remained where she was, intrigued at what would happened and having a contingency plan.
When I started to take photos the Giant Pacific Octopus gradually backed away but had taken a particular interest in a clasp at the end of a bungee cord on Natasha’s gear.
You can see how her arm was entwined around the cord and how there was some flashing of white in the skin. You can also see the Copper Rockfish!
I believe this octopus was a female, thanks to feedback I received from self-admitted Cephalopod Geek supreme, Keely Langford of the Vancouver Aquarium. Octopus males have a “hectocotylus arm”. In Giant Pacific Octopuses, it is the third arm on their right. The hectocotylus stores the spermatophores – packets of sex cells, two of which are handed over to a receptive female who stores them until ready to fertilize her eggs.
Having the good fortune to get photos of the right side of this octopus, particularly #5 and #7, allowed me to see that the top of third arm on the right is not differentiated and that therefore, this was a female.
So what to do when you find a Giant Pacific Octopus on your dive buddy’s head? Observe, marvel, take some photos, share and maybe it can help dispel some of the mythology and vilification about these fabulous marine neighbours.
They have a beak with venom, three hearts, blue blood, and their skin is capable of detecting chemicals (as our nose does).
While many sources report their having 9 brains, octopuses only really have one donut-shaped brain positioned around their oesophagus and then each of their eight arms has many neurons, this is referenced as “distributed intelligence”. Damir Allen explains at this source; “Think of it like a command centre and 8 independent soldiers. They all act semi-independently, and if separated from the main body they will continue to capture food and try to deliver it to a non-existent mouth.”
They are jet propelled and are capable of incredible camouflage where they can not only change the colour of their skin but also its texture to blend in with their surroundings.
They mate only once. From the Vic High Marine website regarding Giant Pacific Octopuses: “Females die directly after they have finished laying and guarding to their egg however males live a slightly longer time. Octopus reproduction starts when a male uses a specialized tentacle [sic, octopuses have arms not tentacles] to pass two spermatophores (sperm packages) to the female. Once given the sperm the female stores the package until she is ready to fertilize the eggs. Before a female is ready to fertilize the eggs she has to find a suitable den. This search can take the future mother up to one month! Once the perfect place is found the female shuts herself in using rocks. From there she fertilizes each egg and gathers them in bundle of approximately 200. She hangs each group of eggs from the ceiling of the cave. This is a long process because, on average, a female octopus can lay up to 50,000 eggs. The incubation time for octopus eggs are six and a half months. During this time the female stays in the cave, not even leaving to eat, attending to the eggs by constantly blowing oxygenated water on to them. When the baby octopuses hatch they are referred to as paralave. These tiny juveniles swim up to the surface joining other zoo plankton and spending weeks feeding on tiny phytoplankton. Once they have developed enough mass they descend to the benthic zone. As for the mother, she waits until all the eggs have hatched then emerges from the cave and dies shortly afterwards due to the starvation she endured during the months she spent devoted to tending her eggs.“
Excellent on-line resources on octopuses.
A Snail’s Odyssey – Learn About Octopus. Includes excellent information on reproduction in Giant Pacific Octopuses.
I am typing with salt still encrusted to my face and hair. I really should warm up from my dive and wash off the NE Pacific before sharing this with you but this is the kind of story you want to shout from the seamount tops. However, be warned, there is a bit of a dark side to the story too.
Today, while doing a shore dive in Port Hardy with the intention of surveying the health of sea stars*, I had the most wondrous experience I have ever had with not one, but two giant Pacific octopuses.
While photographing a sea star I must have disturbed the first octopus because when I looked down, wondering what had caused a massive disruption of hooded nudibranchs from the kelp, there she/he was in full glory – posturing to show me his/her impressive size, hooded nudibranchs undulating all around.
I even ended up with a hooded nudibranch stuck to my mask, which I gently shook off as I am a poor surrogate for kelp!
After I recovered from the shock of this all and mumbled an apology in the guilt of triggering the chaos, I looked at the octopus for a bit . . . and she/he looked at me. We both settled down, apparent in the case of the octopus in that he/she was no longer posturing and reverted to camouflage colours rather than alarm vibrance.
After some minutes, the assessment appeared to be made by this sentient being that I was not a risk; and that there was no need to hide (nor ink!). As a result, for half an hour I was able to (respectfully) follow along as the octopus hunted.
I was allowed to learn about hunting strategy and see how the colour and texture changed as it moved and how the mantle would flash white as it pounced upon prey.
The only thing that stopped this deeply awe-inspiring experience was that dive buddy, Alex Spicer, found a second octopus in the open!
This much smaller octopus was using giant kelp like a hammock.
The divers among you know what a rare gift it is to find one, let alone two, (unhabituated) octopuses out of their dens, certainly during daytime. The underwater photographers and videographers among you would be twitching all the more, knowing what an incredible opportunity this offers to capture the beauty of these giant wonders.
Here’s the dark side. Thankfully it is a literal dark side. My strobes (flashes) didn’t work properly and it was my own doing. It’s been a crazy week of work and, in the flurry resulting from wanting to fit in a dive, I forgot the cables that hook the strobes to the camera.
Yes, I was given what may be the opportunity of a lifetime but failed to fully capture the beauty of it, leaving you with only the grainy images below. However, I got to fully live the experience and had anything changed in the course of events that led to today’s dive, likely I wouldn’t have been octopused at all.
I hope the images are still enough to illuminate the joy and wonder I felt.
[Be sure you scroll down for the photo of the little guy in the kelp hammock!]
It was 7.2° C (45° F) in the ocean yesterday. Even in summer, I’ve only experienced a high of about 10° C.
Typical for Northern Vancouver Island at this time of year, it was also windy enough for us to abort going out for a boat dive.
Windy, chilly, drizzly, grey . . . what’s a cold-water scuba diver to do?
Get in the cold, dark green water however you can because you KNOW what kind of beauty and wonder are always to be found below the surface, even where you moor your boat!
And indeed, under the dock, at only 6 m (20′) we found a Giant Pacific Octopus (Enteroctopus dofleini), curled up on a piling, incredibly tolerant of this ecstatic marine educator. Octopuses are SUCH intelligent animals. I felt as much like I was being scrutinized as he/she must have felt as I observed and photographed this awe-inspiring creature.
This individual was “only” about average size (23 to 42 kg). They can weigh more than 73 kg! I promise many more details on this species in future blog items.
There was so much other beauty under the dock but, for this blog posting, I will leave it at sharing the wonder of this Octo-brr octopus.
Bring on Novem-brrr to Fe-brrr-ary! The cold-water diving is so worth it!
To see these (and additional) images from this octopus photo-shoot at full size, click here.
I would greatly appreciate it if you would let me know, via blog comments, which image (#1 to 6) you believe is the best. This will determine which image ends up in next year’s WILD Northern Vancouver Island Calendar.
From a strict linguistic perspective, the most correct is “octopods” but I choose not to use that. I think if I were to say “octopods” it would distract what I am trying to communicate that is more important that grammar. I might also come across as pretentious and have fewer human friends 🐙. 
He . . . was . . . a . . . fighter.
The Marine Detective 