# data[].attributes.attachment_link.readable_text
Among the smartest animals on Earth, octopuses are unique for being utterly weird in their evolutionary path to developing those smarts. Philosopher Peter Godfrey-Smith has called the octopus the closest thing to an alien that we might encounter on Earth, and their bizarre anatomy speaks to this: An octopus' mind isn't concentrated in its head but spread throughout its body. Their tentacles are packed with neurons that endow each one with a hyperaware sense of touch, as well as the ability to smell and taste. Marine biologists have remarked that each tentacle sometimes seems like it has a mind of its own. Every octopus is a tactile thinker, constantly manipulating its surroundings with a body so soft it almost seems liquid.

All of these things are surprising, at least in theory, because scientists have learned to associate intelligence with vertebrates and a tendency to socialize. Octopuses are either asocial or partially social - and all of them are invertebrates. This raises an obvious question: How did octopuses become so smart?

Scientists know surprisingly little about this subject, as a great deal of the research on octopus neuroanatomy up to this point has focused on one species, the European common octopus ( Octopus vulgaris) - which has about as many neurons in its body as a dog. Thanks to the scientists behind a new study in the scientific journal Current Biology, we now know more about the neural wiring of four very different types of octopuses (or, in one case, octopus-like animals): the vampire squid ( Vampyroteuthis infernalis), which dwells in the deep sea and is technically neither an octopus nor a squid; the blue-lined octopus ( Hapalochlaena fasciata), a venomous creature that keeps to itself while roaming the ocean at night; and "two diurnal reef dwellers," Abdopus capricornicus and Octopus cyanea (also known as the day octopus).
Want more health and science stories in your inbox? Subscribe to Salon's weekly newsletter The Vulgar Scientist.
The scientists also examined data about four other species of coastal octopuses based on material in previously published literature. Using that information and their new research, they concluded that octopus intelligence evolved in ways similar to vertebrate animals - specifically, based on the need to accommodate their surroundings. That implies that they had a convergent evolutionary path towards developing intelligence despite having diverged from vertebrates long ago.

"Our study uncovered new insights to confirm that octopus brain structure indeed evolved as those of many other animals," Dr. Wen-Sung Chung, the lead contact on the paper and a postdoctoral research fellow at the Queensland Brain Institute in Australia, told Salon by email.

Chung analogized octopus evolution to shark evolution, noting that sharks evolved differently based on the ocean depths at which they preferred to swim. "It is probably [unsurprising] as they have a short life span and live in a broad range of ocean (from reef to deep sea, from tropical to temperate waters)," all of which have different conditions in terms of predators to evade and other pressures on survival.

"Octopuses and other cephalopods are very likely more complicated than we expected before," Chung added. "Expanding studies toward various species from different habitats, rather than narrowing down to one/a few iconic species, can be a way to study this amazing and apparently smart creature. I believe we can learn more by embracing the diversity of these creatures."

Among other things, scientists did not expect to find as much folding as they did in the octopus brains. The process in which the brain develops what appear to be wrinkles is known as gyrification, and is associated with vertebrates whose highly evolved brains are capable of processing large quantities of complex information. Yet wrinkles have been observed in brain sections for roughly 20 octopus species already, and the new studies revealed unmistakable new evidence of brain structural folding in the octopod's central nervous system.
RELATED: Do octopuses have souls? "My Octopus Teacher" and the question of octopus consciousness
"The brain folding is certainly a big surprise to us," Chung wrote to Salon. "In order to confirm this, we had to catch different-sized individuals (no way to get them from the animal house or pet shop) to eliminate the possibility of structural deformation caused by the handling during capture, fixation and imaging."

The study also provided new information about the vampire squid, a species that is neither octopus nor squid but rather the last surviving member of its own order. By looking at its brain, scientists were able to learn that it has a strange hybrid of both squid-like and octopus-like features. They also found that, for octopus species that live in reef systems, their entire visual system undergoes major changes to accommodate their daytime-dwelling lifestyle.

Does this mean octopuses are as intellectually complex as humans? Not so fast, Chung warned, noting that scientists can only say for sure that octopuses are smart enough to remember landmarks and break out of their housing tanks. ("This is the nightmare for most octopus researchers," he noted.)

"Honestly, this study is just the very first step to investigate the differences/similarities between octopuses/cephalopods, and we know too little about octopuses in many ways," Chung added. "We should be cautious for this and avoid over-interpretation at this stage until more solid evidence available in the future."

# data[].attributes.attachment_link.title
Scientists peered into an octopus' brain - and were astonished at what they saw

# data[].attributes.attachment_link.description
Among the smartest animals on Earth, octopuses are unique for being utterly weird in their evolutionary path to developing those smarts. Philosopher Peter Godfrey-Smith has called the octopus the closest thing to an alien that we might encounter on Earth, and their bizarre anatomy speaks to this: An octopus' mind isn't concentrated in its head but spread throughout its body.

# data[].attributes.attachment_link.readable_text
Help Save The ENDANGERED

From EXTINCTION!

The Pacific Northwest Tree Octopus

Rare photo of the elusive tree octopus
(Enhanced from cropped telephoto)

The Pacific Northwest tree octopus ( Octopus paxarbolis) can be found in the temperate rainforests of the Olympic Peninsula on the west coast of North America. Their habitat lies on the Eastern side of the Olympic mountain range, adjacent to Hood Canal. These solitary cephalopods reach an average size (measured from arm-tip to mantle-tip,) of 30-33 cm. Unlike most other cephalopods, tree octopuses are amphibious, spending only their early life and the period of their mating season in their ancestral aquatic environment. Because of the moistness of the rainforests and specialized skin adaptations, they are able to keep from becoming desiccated for prolonged periods of time, but given the chance they would prefer resting in pooled water.

An intelligent and inquisitive being (it has the largest brain-to-body ratio for any mollusk), the tree octopus explores its arboreal world by both touch and sight. Adaptations its ancestors originally evolved in the three dimensional environment of the sea have been put to good use in the spatially complex maze of the coniferous Olympic rainforests. The challenges and richness of this environment (and the intimate way in which it interacts with it,) may account for the tree octopus's advanced behavioral development. (Some evolutionary theorists suppose that "arboreal adaptation" is what laid the groundwork in primates for the evolution of the human mind.)

Reaching out with one of her eight arms, each covered in sensitive suckers, a tree octopus might grab a branch to pull herself along in a form of locomotion called tentaculation; or she might be preparing to strike at an insect or small vertebrate, such as a frog or rodent, or steal an egg from a bird's nest; or she might even be examining some object that caught her fancy, instinctively desiring to manipulate it with her dexterous limbs (really deserving the title "sensory organs" more than mere "limbs",) in order to better know it.

Map of estimated tree octopus maximum range, including spawning waters

Tree octopuses have eyesight comparable to humans. Besides allowing them to see their prey and environment, it helps them in inter-octopus relations. Although they are not social animals like us, they display to one-another their emotions through their ability to change the color of their skin: red indicates anger, white fear, while they normally maintain a mottled brown tone to blend in with the background.

The reproductive cycle of the tree octopus is still linked to its roots in the waters of the Puget Sound from where it is thought to have originated. Every year, in Spring, tree octopuses leave their homes in the Olympic National Forest and migrate towards the shore and, eventually, their spawning grounds in Hood Canal. There, they congregate (the only real social time in their lives,) and find mates. After the male has deposited his sperm, he returns to the forests, leaving the female to find an aquatic lair in which to attach her strands of egg-clusters. The female will guard and care for her eggs until they hatch, refusing even to eat, and usually dying from her selflessness. The young will spend the first month or so floating through Hood Canal, Admiralty Inlet, and as far as North Puget Sound before eventually moving out of the water and beginning their adult lives.

Why It's Endangered

Route 101, separating the rainforests of the Olympic Peninsula from Hood Canal

Although the tree octopus is not officially listed on the Endangered Species List, we feel that it should be added since its numbers are at a critically low level for its breeding needs. The reasons for this dire situation include: decimation of habitat by logging and suburban encroachment; building of roads that cut off access to the water which it needs for spawning; predation by foreign species such as house cats; and booming populations of its natural predators, including the bald eagle and sasquatch. What few that make it to the Canal are further hampered in their reproduction by the growing problem of pollution from farming and residential run-off. Unless immediate action is taken to protect this species and its habitat, the Pacific Northwest tree octopus will be but a memory.

The possibility of Pacific Northwest tree octopus extinction is not an unwarranted fear. Other tree octopus species-including the Douglas octopus and the red-ringed madrona sucker-were once abundant throughout the Cascadia region, but have since gone extinct because of threats similar to those faced by paxarbolis, as well as overharvesting by the now-illegal tree octopus trade.

Tree Octopus hat from 1923

The history of the tree octopus trade is a sad one. Their voracious appetite for bird plumes having exhausted all the worthy species of that family, the fashionistas moved on to cephalopodic accoutrements during the early 20th Century. Tree octopuses became prized by the fashion industry as ornamental decorations for hats, leading greedy trappers to wipe out whole populations to feed the vanity of the fashionable rich. While fortunately this practice has been outlawed, its effects still reverberate today as these millinery deprivations brought tree octopus numbers below the critical point where even minor environmental change could cause disaster.

While efforts were made in the past to preserve remaining tree octopus habitat, these were met with resistance by the timber industry, which has traditionally viewed the tree octopus as a nuisance, both because the octopuses favor the valuable, moss-shrouded trees of old growth forests-pitting conservation needs against lucrative sources of lumber-and because octopuses hiding among felled trees often gummed up sawmills and stained pulp vats with their ink.

Traveling sideshow exhibits, such as this one by Glen "Bones" Hartzell from 1942, demonized tree octopuses to the ignorant masses
(Click to enlarge)

These nuisances led many loggers to regard tree octopuses as bad luck, resulting in the pointless killing of octopuses on sight at logging camps in a misguided attempt at eradicating the troublesome species. Anti-octopus sentiment was so strong among loggers that some even began to fear that the octopuses were prone to attacking humans.

These fears were fueled in no small part by gratuitous stories involving tree octopuses harassing lumberjacks and distressing damsels in Northwestern-themed pulp magazines of the 1930-40s and variously "nipping", "entangling", or "suckering the flesh" of the heroes of men's action magazines of the 1950-60s. (The magazine publishers depended on cheap paper made from wood pulp and were glad to contribute to the anti-octopus propaganda campaign of the timber industry.)

To this day, misunderstanding and fear of these gentle creatures can still be found among many old timers, although education campaigns-and special octopus-separators installed at sawmills-have largely halted the practice of tree octopus eradication.

How You Can Help

More Tree Octopus Information

Posters motivate the citizenry to action! Post them!

Tree Octopus FAQs - Frequently asked questions, now with answers.

Tree Octopus Sightings - Includes photos of and behavioral research on the Pacific Northwest Tree Octopus and other tree octopus species.

Tree Octopus In The Media - appearances of tree octopuses, both real and fictional, in the media and popular culture.

Research On Other Tree Octopus Species:

The author of this article and its subsections is Lyle Zapato.
This site is not associated with any school or educational organization,
other than the Kelvinic University branch of the Wild Haggis Conservation Society.
Not to be confused with the Pacific Northwest Octopus Tree.

# data[].attributes.attachment_link.description
Information about the endangered Pacific Northwest Tree Octopus and what you can do to save it.

# data[].attributes.attachment_link.readable_text
The Cephalopod Page is Dr. James B. Wood's personal web page and has been continuously online since 1995. Questions and suggestions are always welcome () but please browse the website first. Additional information on cephalopods can be found on TONMO.com, marine biology at MarineBio.org, and underwater photography at Wetpixel.com/.

Cephalopods, the class of mollusks which scientists classify octopuses, squid, cuttlefish and nautiluses, can change color faster than a chameleon. They can also change texture and body shape, and, and if those camouflage techniques don't work, they can still "disappear" in a cloud of ink, which they use as a smoke-screen or decoy. Cephalopods are also fascinating because they have three hearts that pump blue blood, they're jet powered, and they're found in all oceans of the world, from the tropics to the poles, the intertidal to the abyss. Cephalopods have inspired legends and stories throughout history and are thought to be the most intelligent of invertebrates. Some can squeeze through the tiniest of cracks. They have eyes and other senses that rival those of humans.

The class Cephalopoda, which means "head foot", are mollusks and therefore related to bivalves (scallops, oysters, clams), gastropods (snails and slugs), scaphopoda (tusk shells), and polyplacophorans (chitons). Some mollusks, such as bivalves, don't even have a head, much less something large enough to be called a brain! Yet cephalopods have well-developed senses and large brains. Most mollusks are protected by a hard external shell and many of them are not very mobile. Although nautilus has an external shell, the trend in cephalopods is to internalize and reduce the shell. The shell in cuttlefish, is internal and is called the cuttlebone, which is sold in many pet shops to supply calcium to birds. Squid also have a reduced internal shell called a pen. Octopuses lack a shell altogether.

Cephalopods are found in all of the world's oceans, from the warm water of the tropics to the near freezing water at the poles. They are found from the wave swept intertidal region to the dark, cold abyss. All species are marine, and with a few exceptions, they do not tolerate brackish water.

Cephalopods are an ancient group that appeared in the late Cambrian period several million years before the first primitive fish began swimming in the ocean. Scientists believe that the ancestors of modern cephalopods (Subclass Coleoidea: octopus, squid, and cuttlefish) diverged from the primitive externally-shelled Nautiloidea (Nautilus) very early - perhaps in the Ordovician, some 438 million years ago. How long ago was this? To put this into perspective, this is before the first mammals appeared, before vertebrates invaded land and even before there were fish in the ocean and upright plants on land!

Cephalopods were once one of the dominant life forms in the world's ocean. Today there are only about 800 living species of cephalopods (compare that with 30,000 living species of bony fish, see FishBase). However, in terms of productivity, some scientists believe that cephalopods are still giving fish a run for their money.

Many species of cephalopods to grow very fast, reproduce over a short period of time, and then die. Scientists classify this weed-like life history as "r-selection" - the r refers to exponential growth. If you were to clear cut an oak forest, the first plants to grow would not be more oak trees - it would be weeds. In life history terms, cephalopods are the weeds of the seas. With over-fishing and climate change, there may be more biomass of cephalopods now than anytime in recent history.

# data[].attributes.attachment_link.title
Octopus, Squid, Cuttlefish, and Nautilus - The Cephalopod Page

# data[].attributes.attachment_link.description
The Cephalopod Page is Dr. James B. Wood's personal web page and has been continuously online since 1995. Questions and suggestions are always welcome () but please browse the website first. Additional information on cephalopods can be found on TONMO.com, marine biology at MarineBio.org, and underwater photography at Wetpixel.com/.

# data[].attributes.attachment_link.readable_text
Octopuses are sea animals famous for their rounded bodies, bulging eyes, and eight long arms. They live in all the world's oceans but are especially abundant in warm, tropical waters. Octopuses, like their cousin, the squid, are often considered "monsters of the deep," though some species, or types, occupy relatively shallow waters.

# data[].attributes.attachment_link.description
Octopuses are sea animals famous for their rounded bodies, bulging eyes, and eight long arms. They live in all the world's oceans but are especially abundant in warm, tropical waters. Octopuses, like their cousin, the squid, are often considered "monsters of the deep," though some species, or types, occupy relatively shallow waters.

# data[].attributes.attachment_link.readable_text
Octopuses

Order: Octopoda

Status: Not Listed

Classification: Invertebrate

Description

The octopus is a marine mollusk and a member of the class Cephalopoda, more commonly called cephalopods. Cephalopoda means "head foot" in Greek, and in this class of organisms, the head and feet are merged. A ring of eight equally-long arms surround the head. They use their arms to "walk" on seafloor. The undersides of the arms are covered with suction cups that are very sensitive to touch and taste. The sack-like body is perched atop the head, which has two complex and sensitive eyes, while the mouth is on the underside. Octopuses have a hard beak, which they use to pierce the shells of crustacean prey.

Octopuses have three functioning hearts. Two of the hearts work exclusively to move blood to the gills, while the third pumps blood through the rest of the body. Rather than iron-based blood, their blood is copper-based, which is more efficient at transporting oxygen at low temperatures and makes their blood blue in color.

Octopuses are solitary creatures excellent at camouflaging and concealing themselves. They are about 90 percent muscle, and because they lack bones, they can fit through very small spaces. Their skin contains cells called chromatophores that allow the octopus to change color and pattern. They are believed to be quite intelligent-capable of learning, using tools, and remembering locations.

There is tremendous range in the size of octopus species found in U.S. waters. The giant Pacific octopus (Enteroctopus dofleini), found off the Pacific coast of the United States from California to Alaska, is the largest octopus species in the world. It has an arm span that can reach 14 feet (four meters). The common octopus ( Octopus vulgaris), found along the east coast of the U.S., is much smaller, growing up to about three feet (0.9 meters). The red octopus (Octopus rubescens), found along the Pacific coast, grows to about 20 inches (51 centimeters).

Range

Octopuses are found in every ocean of the world and along every coast of the United States. Octopuses live in coastal marine waters and spend much of their time in dens-small holes and crevices in rocks and coral. They are generally solitary and territorial. Moray eels, fish, seals, sperm whales, sea otters, and many birds prey on octopuses. Octopuses use several different strategies to evade predators-they camouflage themselves by quickly changing their skin color, they make colorful displays or eject ink to startle or confuse potential predators, they squeeze into small crevices to escape, and they quickly propel themselves through water.

Diet

Newly hatched octopuses will eat small foods such as copepods, larval crabs, and sea stars. Adult octopuses feed on crabs, clams, snails, small fishes, and even other octopuses. All species of octopus have venom of varying levels of toxicity, which they inject using a beak that is similar to a bird's. They typically hunt at night, pouncing on their prey and wrapping it in the webbing between their arms. They penetrate hard-shelled prey with their beaks.

Life History

The male initiates mating by approaching the female. He has a specialized tip at the end of one arm that transfers sperm to the female's oviduct. The female looks for a suitable den site and lays the eggs, attached in chains, to the rock or coral or the den. The eggs can number in the hundreds of thousands for some species. The female guards and cares for the eggs, aerating and cleaning them until they hatch. As soon as they hatch, the young are able to swim, eat, and produce ink. The male parent dies soon after mating and the female survives only until her brood has hatched. An octopus will generally live for about one to three years, depending on the species.

Conservation

Octopuses are spread throughout a large ocean area and are solitary, which makes it difficult to determine the status of their populations. They are not believed to be under threat, but they are sensitive to pollutants. Scientists are still discovering new species of octopuses.

Fun Fact

Octopuses move using jet propulsion-they suck water into their mantle cavity, then quickly contract their muscles to force the water out through a narrow siphon, aiming the water to steer in a particular direction.

Sources

Alaska Fisheries Science Center, NOAA Fisheries, National Oceanic and Atmospheric Administration

Animal Diversity Web, University of Michigan Museum of Zoology

Maui Ocean Center

Monterey Bay Aquarium

National Aquarium

Smithsonian's National Zoo and Conservation Biology Institute

Smithsonian Magazine

What Behavior Can We Expect of Octopuses?, by J.A. Mather and R.C. Anderson, The Cephalopod Page

# data[].attributes.attachment_link.description
Learn facts about the octopus's habitat, diet, life history, and more.

# data[].attributes.attachment_caption
How to Know If a Source Is Reliable by Shmoop

# data[].attributes.attachment_link.title
Y2Mate.is - How to Know If a Source Is Reliable by Shmoop-m_EAxomGhNY-480p-1651661034980.mp4

# data[].attributes.body
the author made up this article

# data[].attributes.body
It's not .gov .org or .edu

The author isn't an expert

It has ads

No references to other experts

Don't know if its current.

# data[].attributes.body
It's a .com

The author is an expert I think

It has ads

it references to other experts

Its current

# data[].attributes.body
It's a .org

The author is an expert

It's ad free

It doesn't reference to other experts

Don't know when it was published

# data[].attributes.body
Its  .edu

The author is an expert

No ads

No references to other experts

I don't know if its current

# data[].attributes.body
It's not .edu .gov or .org

The author is an expert

It's not ad free

It doesn't refer to other experts

I don't know when this was published