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Researchers have only recently determined that octopuses can 'see' (detect light) via their tentacles and react to that light perception. This novel sensory capability was previously unsuspected.
Octopuses can 'see' light with their arms

Octopuses can "see" light with their arms, even when their eyes are in the dark, researchers have found. When the arms of the octopus detect light, the eight-armed creature pulls them close to their body.

Because octopuses generally have a poor sense of where their body is in space, this complex instinctive behavior might help protect their arms from the pincers of predators nearby that they might otherwise not sense.

Scientists have long known that octopus arms react to light. Their skin is covered in pigment-filled organs called chromatophores that reflexively change color when exposed to light. These chromatophores are responsible for the octopus's color-changing camouflage superpowers. ...

Their new experiment involved placing an octopus in a tank covered in an opaque black tarp. The octopus, kept in the dark, was trained to reach an arm through a small hole in the top of the tank to find pieces of fish. While the octopus was blindly feeling around for a piece of food, the researchers would shine a bright light on the octopus's arm at a random time; about 84% of the time when they shone the light, the octopus would rapidly pull its arm away ...

Having established that octopus arms can sense and react to light, their next step was to explore what controls this reaction. Is it a simple reflex controlled completely by neurons — or special nerve cells —in the arm, or is it controlled by the brain? ...

... the studies suggest that the arm is sensing the light, sending a message to the brain through nerves in the muscle, and the brain is telling the octopus to move the arm.

"The fact that this behavior is not a reflex, but instead controlled by higher-level cognition in the brain is fascinating" ...
FULL STORY: https://www.livescience.com/octopus-sees-light-with-arms.html
 
Here are the bibliographic details and abstract for the published study ...

Feel the light: sight-independent negative phototactic response in octopus arms
Itamar Katz, Tal Shomrat, Nir Nesher
Journal of Experimental Biology 2021
224: jeb237529
doi: 10.1242/jeb.237529 Published 5 March 2021

ABSTRACT
Controlling the octopus's flexible hyper-redundant body is a challenging task. It is assumed that the octopus has poor proprioception which has driven the development of unique mechanisms for efficient body control. Here we report on such a mechanism: a phototactic response of extraocular photoreception. Extraocular photoreception has been observed in many and diverse species. Previous research on cephalopods revealed that increased illumination on their skin evokes chromatophore expansion. Recently, the mechanism was investigated and has been termed ‘light-activated chromatophore expansion’ (LACE). In this work we show that in response to illumination, the arm tip reacts in a reflex-like manner, folding in and moving away from the light beam. We performed a set of behavioral experiments and surgical manipulations to elucidate and characterize this phototactic response. We found that in contrast to the local activation and control of LACE, the phototactic response is mediated by the brain, although it is expressed in a reflex-like pattern. Our research results and observations led us to propose that the phototaxis is a means for protecting the arms in an instinctive manner from potential daytime predators such as fish and crabs, that could identify the worm-like tips as food. Indeed, observations of the octopuses revealed that their arm tips are folded in during the daytime, whereas at night they are extended. Thus, the phototactic response might compensate for the octopus's poor proprioception by keeping their arms folded in illuminated areas, without the need to be aware of their state.

SOURCE: https://jeb.biologists.org/content/224/5/jeb237529
 
Latest report strongly suggests that octopi dream, and dream perchance to learn:
https://www.cell.com/iscience/fulltext/S2589-0042(21)00191-7

"The recent evidence of ‘Active Sleep’ in Drosophila suggests strong selection pressure across evolution for an alternation between ‘Quiet’ and ‘Active’ sleep states. The occurrence of the non-REM/REM alternation in mammals, birds, and in some reptiles, such as in the bearded dragon and in the argentine tegu Salvator merianae, points to a common origin of the wake-sleep cycle in these groups of animals, which share a common ancestor.

However, considering that cephalopods split from vertebrates more than 500 million years ago, it is likely that the sleep behaviors observed here, despite their similarity to those found in amniotes, are analogous rather than homologous to these states. . . . Cephalopods have evolved de novoneural structures termed lobes, including the vertical lobe that is involved in long-term memory and shares some functional features with the mammalian hippocampus. Indeed, cephalopod evolution seems to have converged with vertebrates with regard to the neural mechanisms underlying learning. It remains to be investigated whether the physiological functions of sleep, in this far-evolving taxon, also resemble the functions performed in amniotes, such as metabolic detoxification and cognitive processing."
 
A bit commercial, but a great video for general information about octopus intelligence and biology.
It includes some really fabulous footage.
(I guess it has to be paid for somehow!)
 
Footage of rarely seen glass octopus

Short video of translucent octopus filmed in Pacific Ocean.

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Having a stroll. Vid at link/

Two octopuses were rescued by walkers after they were spotted crawling along a beach.

The cephalopods had washed up at New Quay, Ceredigion, where they were found by Fran Fitzpatrick and Joshua Pedley.

They had decided to see if there was anything interesting on the sands after Storm Franklin and were able to help them back into the sea.

Wildlife guide Mr Pedley said: “To our knowledge both octopus are still safe and sound.”

https://www.bbc.com/news/av/uk-wales-60516908
 
Ancient Octopus/Squid bloodsucker.

About 330 million years ago in what’s now Montana, a squidlike creature died in a tropical bay and its soft body was preserved in limestone.

Now, paleontologists at the American Museum of Natural History and Yale University have studied the fossilized remains and named the unusual 10-armed creature in honor of U.S. President Joe Biden.

The creature was about 12 centimeters long and had a torpedo-shaped body, with a pair of fins at one end that likely helped stabilize it as it swam. It also had an ink sack and 10 sucker-bearing arms (see image, above), the scientists report today in Nature Communications. Two of the arms seem to be longer than the rest, similar to the two long tentacles that accompany the eight arms of modern-day squid. (Cephalopod arms have suckers throughout, which help them grasp prey, whereas tentacles only have suckers at the very end.)

The researchers say the animal is the oldest known vampyropod—an ancestor of modern octopuses and vampire squids (despite their name, vampire squids are not classified as squids—they inhabit their own branch of the tree of life.) The fossil dates to about 330 million years ago, which corroborates genetic studies indicating vampyropods diverged from their squid ancestors around that time. ...

https://www.science.org/content/article/newly-discovered-octopus-ancestor-had-10-arms
 
Rynner eaten alive as Cornwall is overrun by plage of octopusses.

Unusually high numbers of octopus have been seen along the Cornish coast this month.

Cornwall Wildlife Trust (CWT) said it had been a "bumper year" for sightings. Divers and snorkellers have reported increased numbers, and one fisherman caught 150 in a day, compared to his usual total of one or two a year. CWT said the last significant population boom for octopus was recorded on England's south coast was recorded in 1948.

It is not known whether this year will classify as the first octopus boom in more than 70 years.

The Common Octopus is a large species and is usually recorded by CWT once or twice a year on average.

Matt Slater, marine conservation officer at CWT, said: "I got really excited when I started receiving messages from our Seasearch divers - not only because sightings of these striking animals are few and far between, but because they'd seen several of them on one dive. They are such amazing, alien creatures - one of the most intelligent animals in our oceans - and to witness a population explosion in our local waters would be incredible."

https://www.bbc.com/news/uk-england-cornwall-61987374
 

‘It was giving me a hug’: video captures rare giant octopus encounter

Canadian diver captures footage of the cephalopod drawing closer and closer until it fully embraces her

On a cloudy morning, Andrea Humphreys and a group of friends slipped into the waters of the Salish Sea, off the eastern coast of Vancouver Island.

“People say it’s dark and gloomy here. But when you’ve got lights, you see every colour of the rainbow. It’s incredible. I’ve completed more than 675 dives and I think this is some of the best diving in the world,” she said. The group was also on the hunt for an enigmatic local: the giant Pacific octopus.

Humphreys said that she occasionally spots them sheltering in their dens, but this time, within moments of immersion, the group made the rare sighting of an octopus out in the open.
It quickly approached her friend, grazing its tentacles up against the mask and regulator.

Humphreys started photographing the encounter – until the octopus had turned its attention to her.

Her camera captured the curious cephalopod drawing closer and closer, its tentacles widening until it fully embraced her.

“It was just crawling on my camera, crawling on my lips, giving me a hug. These huge tentacles were up over my face and mask,” Humphreys said. “Every time I backed away from it, the octopus just kept coming towards me. And it was just so amazing and inspiring.”

For the next 40 minutes, the octopus stayed close by, inspecting her dive equipment and taking a particular interest in her camera. “It kept changing the lights on my camera system and fiddling with it,” she said.

Throughout the encounter, the octopus maintained its deep red colour, never taking on the greyish tone of a fearful or aggressive cephalopod.
1668001676557.png


video at link.
 
Woman's video of accidentally catching giant octopus is giving people nightmares

People have been left horrified after a woman caught ‘the Kraken’ while out fishing in Canada.

Brooke Sattar, from Vancouver Island, was out fishing with some pals at the Alberni Inlet recently, when she started to pull in a particularly heavy prawn trap.

Naturally, Sattar initially assumed this meant the trap had done its job and was full of prawns, but as she pulled it out of the water, she soon realised it was actually a huge octopus - believed to be a northern giant Pacific octopus, the ‘largest, longest-lived octopus species’, according to Nature Conservancy of Canada.

resize


Sattar said: “We pulled up a big octopus. It held on for two or three minutes, it wasn’t long at all and then it just let go and swam away.”

The northern giant Pacific octopus usually grows to around five metres in length and 20 to 50 kilograms, but the largest ever to be recorded came in at a whopping 9.1 metres long and weighed 272kg.

https://www.unilad.com/news/woman-removes-giant-hawk-from-house-20220402

maximus otter
 
Yes, it could well have been. After all, it did appear once as a cat so why not an octopus?
 
Rarely-seen giant Pacific octopus spotted swimming in Oregon tide pool

The U.S. Department of the Interior shared a video on its Facebook page Thursday of a Giant Pacific octopus squirming through the Yaquina Head tide pools on the Oregon coast. This amazing creature is sighted at this spot only a few times a year, according to the department.


This particular octopus is actually quite small. The Giant Pacific octopus can grow as large as 16 feet long and averages around 110 pounds at maturity, according to Oregon State University.

If you spot one in the wild, make sure to keep your distance. While not likely deadly, their venom is hazardous to humans.

https://www.oregonlive.com/news/202...ted-at-yaquina-head-tide-pools-in-oregon.html

maximus otter
 
The America History Channel presented argument that octopuses are from another world.

The channel used the Mimic Octopus as an example that has 3 hearts and 9 brains.

This octopus is extremely smart and can mimic 15 marine animals.

The real twist is this octopus has an amazing 33,000 genes which makes it not related to anything else on earth.

The History Channel feels that this octopus ability to change form could be the basis for werewolves and skinwalkers having the ability to shape change.

For all we know non earth humanoids have been living among us for years ?
 

Deadly blue-ringed octopus with enough venom to kill 20 humans bites woman swimming

The blue-ringed octopus may look tiny but its venom packs a punch, with tetrodotoxin being strong enough to kill 20 humans by paralysing the body and stopping the victim from being able to breathe

The woman, who is in her 30s, was nipped after the tiny creature fell out of a shell she picked up at Chinaman's Beach in Mosman, Australia at around 2.45pm local time Thursday (03.45am GMT).

The tiny 10cm-long creature fell out of the shell and stung her twice, it was reported.

On arrival, paramedics administered first aid after she reported feeling excruciating pain around the affected area.

An ambulance rushed her to Royal North Shore hospital for further treatment.

She was reportedly in a stable condition and being monitored by medics.

"A blue-ringed octopus bite is a rare call for us but they are extremely venomous," NSW Ambulance Inspector Christian Holmes said in a statement.

Though its smaller than the human palm, the blue-ringed octopus carries venom - called tetrodotoxin - strong enough to kill 20 humans.

The poison can induce paralysis, leaving the lungs unable to breathe.

It is 1000 times more toxic than cyanide and there is currently no antivenom.

The only way someone can survive the gruelling condition is by being put on a ventilator to wait for the poison to leave the bloodstream.

On paper, the venom is infamous for its lethality, but there have only been a handful of confirmed casualties.
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The octopuses are probably fighting back in response to going from 'occasional catch' to 'being farmed'.

World's first octopus farm proposals alarm scientists
A plan to build the world's first octopus farm has raised deep concerns among scientists over the welfare of the famously intelligent creatures.
The farm in Spain's Canary Islands would raise about a million octopuses annually for food, according to confidential documents seen by the BBC.
They have never been intensively farmed and some scientists call the proposed icy water slaughtering method "cruel."

https://www.bbc.co.uk/news/science-environment-64814781
 

Deadly blue-ringed octopus with enough venom to kill 20 humans bites woman swimming

The blue-ringed octopus may look tiny but its venom packs a punch, with tetrodotoxin being strong enough to kill 20 humans by paralysing the body and stopping the victim from being able to breathe

The woman, who is in her 30s, was nipped after the tiny creature fell out of a shell she picked up at Chinaman's Beach in Mosman, Australia at around 2.45pm local time Thursday (03.45am GMT).

The tiny 10cm-long creature fell out of the shell and stung her twice, it was reported.


View attachment 64374

These things are deadly. Very deadly and very small. They live all around the Sydney coastline in tidal pools and as you can see from the image above, quite pretty (as far as octopi go). There's plenty of videos online of tourists picking these things up and holding them in the palm of their hand only to have a local come screaming over shouting at them to drop it.
We were all taught from a young age, look but don't touch.


Read the comments, some of them are priceless (though true).
 
https://www.livescience.com/why-octopus-moms-self-destruct
Octopuses torture and eat themselves after mating. Science finally knows why.
News
By Stephanie Pappas
published May 18, 2022

She even eats pieces of her own arms.

Many animal species die after they reproduce. But in octopus mothers, this decline is particularly alarming: In most species, as an octopus mother's eggs get close to hatching, she stops eating. She then leaves her protective huddle over her brood and becomes bent on self-destruction. She might beat herself against a rock, tear at her own skin, even eat pieces of her own arms.

Now, researchers have discovered the chemicals that seem to control this fatal frenzy. After an octopus lays eggs, she undergoes changes in the production and use of cholesterol in her body, which in turn increases her production of steroid hormones — a biochemical shift that will doom her. Some of the changes may hint at processes that explain longevity in invertebrates more generally, said Z. Yan Wang, an assistant professor of psychology and biology at the University of Washington.

"Now that we have these pathways, we're really interested to link them to individual behaviors, or even individual differences in how animals express these behaviors," Wang told Live Science.

Programmed to die

Even as an English-major undergraduate student, Wang was intrigued by female reproduction, she said. When she transitioned into graduate school in science, she kept that interest, and was struck by the dramatic deaths of octopus mothers after they laid their eggs. No one knows the purpose of the behavior. Theories include the idea that the dramatic death displays draw predators away from eggs, or that the mother's body releases nutrients into the water that nurture the eggs. Most likely, Wang said, the die-off protects the babies from the older generation. Octopuses are cannibals, she said, and if older octopuses stuck around, they might end up eating all of each other's young.


A 1977 study by Brandeis University psychologist Jerome Wodinsky found the mechanism behind this self-destruction lay in the optic glands, a set of glands near the octopus's eyes that is roughly equivalent to the pituitary gland in humans. If the nerves to the optic gland were cut, Wodinsky found, the mother octopus would abandon her eggs, start eating again and live for another four to six months. That's an impressive life extension for creatures that live only about a year.

But no one knew what the optic gland was doing to control this cascade of self-injury.

"From the very beginning, I was really keen to do the experiments that we outlined in the paper we just published, which is essentially juicing the optic gland and then identifying the components of that juice," Wang said.

Wang and her colleagues analyzed the chemicals produced in the optic glands of California two-spot octopuses (Octopus bimaculoides) after they laid eggs. In 2018, a genetic analysis of the same species showed that after egg-laying, the genes in the optic glands that produce steroid hormones (which are built, in part, with cholesterol components) started going into overdrive. With that study as a guidepost, the scientists focused on the steroids and related chemicals produced by the optic glands in the two-spot octopuses.


They found three separate chemical shifts that occurred around the time the octopus mother laid her eggs. The first was a rise in pregnenolone and progesterone, two hormones associated with reproduction in a host of creatures (in humans, progesterone rises during ovulation and during early pregnancy). The second shifts were more surprising. The octopus mothers began to produce higher levels of a building block of cholesterol called 7-dehydrocholesterol, or 7-DHC. Humans produce 7-DHC in the process of making cholesterol too, but they don't keep any in their systems for long; the compound is toxic. In fact, infants born with the genetic disorder Smith-Lemli-Opitz syndrome can't clear 7-DHC. The result is intellectual disability, behavioral problems including self-harm, and physical abnormalities like extra fingers and toes, and cleft palate.


Finally, the optic glands also began producing more components for bile acids, which are acids made by the liver in humans and other animals. Octopuses don't have the same kind of bile acids as mammals, but they do, apparently, make the building blocks for those bile acids.

"It suggests that it is a brand new class of signaling molecules in the octopus," Wang said.

The bile acid components are intriguing, Wang said, because a similar set of acids has been shown to control the life span of the worm Caenorhabditis elegans, which is commonly used in scientific research because of its simplicity. It may be that the bile acid components are important for controlling longevity across invertebrate species, Wang said.

Octopuses are hard to study in captivity because they require a lot of space and perfect conditions for them to grow to sexual maturity and breed. Wang and other octopus researchers have now worked out a way to keep the lesser Pacific striped octopus (Octopus chierchiae) alive and breeding in the lab. Unlike most other octopus species, Pacific striped octopuses can mate multiple times and brood multiple clutches of eggs. They don't self-destruct as their eggs get ready to hatch, making them perfect specimens for studying the origin of the morbid behavior.

"I'm really, really excited to study the dynamics of the optic gland in that species," Wang said.

The researchers published their findings May 12 in the journal Current Biology (opens in new tab).
 

Biologists Have Discovered an Underwater Octopus City And They're Calling It Octlantis


At the end of last year, scientists discovered a small octopus city – dubbed Octlantis – a find that suggests members of the gloomy octopus species (Octopus tetricus) are perhaps not the isolated and solitary creatures we thought they were.

Octlantis features dens made out of piles of sand and shells, and is home to up to 15 of the cephalopods, according to marine biologists. They recorded 10 hours of video footage of the site, which lies 10 to 15 metres (33 to 49 feet) under the water and measures 18 by 4 metres (59 by 13 feet).

octlantis-octopus-tetricus-768x506.jpg


The international team of researchers saw the gloomy octopuses meeting up, living together, communicating with each other, chasing unwelcome octopuses away, and even evicting each other from dens – so it seems Octlantis can be quite a rough place to live.

"These behaviours are the product of natural selection, and may be remarkably similar to vertebrate complex social behaviour," lead researcher David Scheel, from Alaska Pacific University, [said].

"This suggests that when the right conditions occur, evolution may produce very similar outcomes in diverse groups of organisms."

The new octopus city lies in Jervis Bay on the coastline of eastern Australia, and is close to another similar site discovered in 2009 called Octopolis.

https://www.sciencealert.com/marine...r-octopus-city-octlantis-jervis-bay-australia

https://en.wikipedia.org/wiki/Octopolis_and_Octlantis

maximus otter
 

Biologists Have Discovered an Underwater Octopus City And They're Calling It Octlantis


At the end of last year, scientists discovered a small octopus city – dubbed Octlantis – a find that suggests members of the gloomy octopus species (Octopus tetricus) are perhaps not the isolated and solitary creatures we thought they were.

Octlantis features dens made out of piles of sand and shells, and is home to up to 15 of the cephalopods, according to marine biologists. They recorded 10 hours of video footage of the site, which lies 10 to 15 metres (33 to 49 feet) under the water and measures 18 by 4 metres (59 by 13 feet).

octlantis-octopus-tetricus-768x506.jpg


The international team of researchers saw the gloomy octopuses meeting up, living together, communicating with each other, chasing unwelcome octopuses away, and even evicting each other from dens – so it seems Octlantis can be quite a rough place to live.

"These behaviours are the product of natural selection, and may be remarkably similar to vertebrate complex social behaviour," lead researcher David Scheel, from Alaska Pacific University, [said].

"This suggests that when the right conditions occur, evolution may produce very similar outcomes in diverse groups of organisms."

The new octopus city lies in Jervis Bay on the coastline of eastern Australia, and is close to another similar site discovered in 2009 called Octopolis.

https://www.sciencealert.com/marine...r-octopus-city-octlantis-jervis-bay-australia

https://en.wikipedia.org/wiki/Octopolis_and_Octlantis

maximus otter
That's a rather shoddy use of the word "city". How about "communal lair"; it would seem more appropriate. In any case, fifteen occupants is more like a hamlet than a city.
 
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