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  • In many ways, the octopus is as close to alien life as we may ever see. Few creatures in

  • the world are as remarkable and bizarre. A part of a class of animals called cephalopods,

  • they are among the most intelligent and most mobile of all the invertebrates. They live

  • in every ocean in the world, in the deep sea, in kelp forests, in coral reefs, along rocky

  • shorelines. And they are as diverse as the habitats they live in. They can be massive,

  • or absolutely tiny. Some species are venomous, and some are just downright strange. In any

  • given moment, they can appear spikey, or they can appear smooth. They are so different from

  • us, that most of their 500 million neurons are not in their brain, but in their arms,

  • which can smell and taste, and even think. And so intelligent that their cognitive ability

  • matches that of many large-brained vertebrates.

  • They have left scientists stunned about how a creature so far from us on the evolutionary

  • tree could evolve such complex behaviors, their intelligence emerging in an entirely

  • novel and independent way from our own.

  • So how did the octopus become so biologically complicated - an island of complexity in the

  • sea of invertebrate animals? Just how intelligent are they, and how can studying them reveal

  • information about our own minds?

  • Cephalopods have been around for a long time. Fossil records show that they evolved over

  • 500 million years ago - long before any fish, reptiles, or mammals appeared on earth. The

  • early ancestor of the octopus was quite small and had a shell, which it used to protect

  • itself as it crawled along the ocean bottom. Cephalopods are, after all, members of the

  • mollusk phylum. A group of creatures that are usually slow and simple, with soft bodies

  • and a hard protective shell - like snails, clams, and oysters. But around 140 million

  • years ago, the lineage that produced the octopus lost their shells, making them nimble, agile

  • creatures, but in the process also made them rather vulnerable. Survival of these soft

  • bodied creatures for so many millions of years therefore seems unlikely in a sea full of

  • dangerous, hungry predators. But this vulnerability and selective pressure may be precisely what

  • has allowed the octopus to become the remarkable creature we know today.

  • Because an octopus has almost no hard parts at all, except its beak, it can squeeze through

  • any hole as long as it’s larger than its eyeball. This allows the octopus to hide in

  • very small crevices - a certain evolutionary advantage when escaping large predators like

  • sharks or dolphins. But, the soft-bodied octopus evolved an even more clever way of evading

  • detection: they are masters of disguise.

  • Watching this clip of an octopus, you can see just how quickly and drastically it can

  • change colors. In slow motion reverse, you see the color change spread across its body.

  • The 3D texture of the skin also changes, to match the surrounding seaweed and coral. In

  • the blink of an eye, it has almost completely blended in with its surroundings. Cephalopod

  • camouflage is among the most dynamic in the animal kingdom, and relies on a system of

  • extremely sophisticated tissues.

  • Chromatophores are organs that are speckled across the skin of the octopus, like freckles.

  • They contain tiny pigment filled sacs, like little balloons full of different color dye,

  • which can be black, red or yellow. The pigment sacs are surrounded by radial muscles, which

  • can stretch the sac to reveal the pigment’s color. Just like balloons full of dye, when

  • stretched, their pigment color appears bright and vibrant. Depending on which sets of sacs

  • an octopus opens or closes, it can produce patterns such as bands, stripes, or spots

  • - helping to turn itself into a rock, a coral, or kelp in an instant.

  • But if the octopus needs to produce colors outside of black, red, and yellow, it uses

  • another layer of reflective structures in their skin called iridophores. They are stacks

  • of very thin cells that lay beneath the chromatophores. They contain a protein called reflectin that

  • bounces certain wavelengths of light back out. They are responsible for the metallic

  • blues and greens that appear to shimmer on the skin of the octopus.

  • Beneath that layer is yet another layer of reflective tissue, called leucophores. These

  • reflect ambient light, usually producing white hues. By combining reflection from the iridophores

  • and leucophores with the correct patterning of chromatophores, the octopus can create

  • a very convincing copy of its surroundings.

  • But the octopus has one more trick up its sleeve, allowing it to disappear in plain

  • sight almost completely. Using a structure called papillae, it can change the texture

  • of its skin, creating ridges and bumps that rise and fall. This helps the octopus match

  • its surroundings even better. It also gives them a less identifiable edge. Many vertebrate

  • predators find their prey by looking for visual edges and breaks in the background, and this

  • tactic disrupts that very effectively.

  • With all these tools, the shell-free, soft bodied octopus has been able to deceive an

  • ocean full of predators for millions of years. But, their survival has not hinged on these

  • camouflage properties alone. It is the way they are controlled that is perhaps an even

  • more compelling survival tool.

  • When an octopus travels along the seafloor, they have to assess the background and modify

  • their camouflage constantly. They are making decisions at a rapid pace - one researcher

  • observed an octopus changing its camouflage 177 times in 1 hour. Octopus’s camouflage

  • reaction times are faster than any other animals’, - up to 200 milliseconds, as fast as the fastest

  • blink you can do.

  • But despite doing so much with color, the octopus, and almost all cephalopods, are surprisingly

  • thought to be colorblind. How can they match colors they can’t even see?

  • In 2015, the answer to this question started to be uncovered. Researchers found that the

  • skin of an octopus is sensitive to light, due to photoreceptor genes active in the skin.

  • Even when the skin was detached from the body, it could respond to light and change the shape

  • of its chromatophores. Scientists realized that an octopus can see with not just its

  • eyes, but also its skin.

  • But as the octopus body was evolving its color changing defense mechanisms when it lost its

  • shell 140 million years ago, another transformation occurred: the development of its large brain

  • and nervous system. The photoreceptor genes in the skin work in connection with the octopus’s

  • large and complex brain. The octopus can change color so fast, because the octopus controls

  • its chromatophores neurally. Other animals that can change color, like chameleons, for

  • example, take much longer because their color change is hormonally controlled. Hormones

  • take time to get into the blood and distribute around the body. A color change can take over

  • 20 seconds when controlled this way.

  • Some researchers believe that color change in the octopus may be like breathing or blinking

  • for us- something it can choose to do, but also something that can happen involuntarily.

  • It can have awareness from its eyes and brain, but also throughout its body.

  • The octopus nervous system is large like ours, but built with a different relationship between

  • body and brain all together. The common octopus has around half a billion neurons in its body.

  • For comparison, humans have about 100 billion. Most invertebrates usually have much less.

  • Snails have only 20,000. But cephalopods like the octopus score in the same range as many

  • vertebrates, like cats and dogs and parrots - more than any other invertebrate

  • And of their 500 million neurons, only a third are found in their brain. The majority are

  • found in their eight arms. And as strange as it sounds, this allows the octopus to in

  • a way, think with its arms.

  • For a long time, scientists have known that a severed octopus arm can respond to stimuli

  • an hour after being separated from the central brain. But a paper last year began to reveal

  • the extent of this autonomy. Using video modelling they observed the octopus as it explored objects

  • in its tank and looked for food. The program quantified movements of the arms, tracking

  • how the arms work together in synchrony, suggesting direction from the brain, or asynchronously,

  • suggesting independent decision-making in each appendage. And they found that in the

  • flow of information from the environment to the octopus, some information bypasses the

  • central brain entirely. The suckers and arms can, in a way, think for themselves, allowing

  • the octopus to analyze its environment extremely quickly, and react with matching speed. Along

  • with skin that can perceive and change color on its own, the relationship between brain

  • and body in the octopus is full of blurred lines.

  • And on top of this unusual neural layout and strange body autonomy, cephalopods are smart

  • - extremely smart - and this is really what gives the octopus its alien-like status. They

  • are so far from any other intelligent life on the tree of evolution, but still compete

  • with vertebrates in their raw cognitive ability. Evolution invented intelligent life not once,

  • but twice, in two completely different ways.

  • In the evolutionary tree of life, we sit upon the branch of mammals. Nearby are the fish,

  • reptiles, birds, amphibians - the other members of the larger classification of vertebrates.

  • This group is where we see all of theintelligentlife we normally think of - humans, primates,

  • dogs, cats, dolphins, and some birds. When we collect these animals and trace back to

  • our common ancestor, it was likely a lizard-like animal that lived around 320 million years

  • ago. Like us, this animal would have had a backbone, four limbs, a head, and a skeleton.

  • It would have walked around, well adapted to land, and had a well developed central

  • nervous system.

  • But to find where we split from the octopus, we have to travel much further down the branches

  • - to around 600 million years ago. The creature we find there is a simple, flat worm. It had

  • an extremely basic nervous system, and no inklings of what we would considerintelligence.’

  • As the evolutionary tree branched and diverged, intelligence blossomed on our branch of vertebrates,

  • and totally separately, in the cephalopods. [7] And, with the cephalopods evolving before

  • any of the intelligent vertebrates, it's likely that they were the first intelligent animals

  • that appeared on earth.

  • But what actually isintelligence? How can we identify - or even measure - such a

  • thing in an animal so different to us?

  • In humans, intelligence is commonly defined as the ability to think abstractly, understand,

  • communicate, problem-solve, learn, form memories, and plan actions. This is usually measured

  • by intelligence tests which can be given a numerical value. But, we can not give a standardized

  • test to an octopus. We can only observe their behaviors.

  • - “they're the most interesting mollusks in

  • terms of behavior. No question.”

  • To learn more about the depth of octopus intelligence as researchers currently understand it, I

  • spoke with Jennifer Mather, professor in the Department of Psychology at University of

  • Lethbridge - and scientific advisor for the film My Octopus Teacher.

  • every learning task you give them they can do. Short term, long term spatial memory,

  • object perception. But it's more than learning. They also go in for planning. And planning

  • is not so obvious.

  • One of the famous examples is what’s been called a coconut carrying octopus. So the

  • octopus is going off to a place where there's no shelter. And it takes these coconut halves

  • with them. And when it wants to stop and rest, it picks them up and brings them up like this

  • around it. It's amazing.”

  • Some scientists argue that this behavior is a rare example of composite tool use - a behavior

  • previously thought to only exist in humans, some primates, and some birds. And it may

  • be evidence of complex intelligence for two reasons. First, this tool use might represent

  • a behavioural innovation allowing octopuses to protect themselves in areas where they

  • cannot otherwise hide. Second, because the coconut shells are transported, with great

  • effort, to meet future needs this behaviour might indicate an octopus’s planning ability.

  • The octopus has to imagine the future and connect the dots between past events, current

  • actions, and future events, which is not a simple task.

  • Octopuses also do well in memory tests, and can differentiate between different people,

  • even when they are wearing the same outfit. Octopuses are also great problem solvers.

  • For instance, they remove lids from jars and open opaque boxes to acquire hidden prey.

  • And, in a study done by Professor Mather, the common octopus has also been shown to

  • be extremely playful.

  • I would describe them as extremely exploratory, sort of like a five year old kid, taking stuff

  • apart, going off and feeling around with the landscape, just grabbing more information.

  • Play is often defined as a behavior that is not necessary for survival, done on purpose,

  • but seemingly for pleasure. The action is often repeated, exaggerated, and carried out

  • when the animal is adequately fed, healthy, and not under stress.

  • We figured that the animals are more likely to play if theyre safe and bored. So we

  • set up octopuses in an aquarium with a place to hide, and nothing else. And then we got

  • a pill bottle, put enough water in it, but it floated at the surface.

  • Also in the mix was a water intake pump for the aquarium that the researchers hadn’t

  • necessarily intended to be part of the experiment. It created a current that pushed the pill

  • bottle across the top of the tank, which sparked the curiosity of some of the octopuses.

  • So we did this with six animals, okay, in two cases, the pill bottle came across like

  • this. The octopus shot a jet of water at it, which meant that it went back towards the

  • water intake and it came back again.

  • If an octopus did this once, or even twice, it would not be experimentally significant.

  • But a few carried out this behavior so many times that it couldn’t be ignored.

  • one of them did this, I think it was 14 times. And one of them did it 21 times.

  • it was the marine equivalent of bouncing the ball!

  • In addition to helping establish motor coordination, play in most species is largely needed for

  • social purposes - for establishing social rank, for learning social rules, or for social

  • bonding. And due to its complexity, play is considered to be almost exclusive to mammals,

  • with a few exceptions in other vertebrates like some birds.

  • But the octopus is a solitary creature. It has no social bonds, no social hierarchy.

  • It makes us rethink the evolutionary reasons for play. In fact, much of our idea of intelligence

  • is based on the idea that it evolved out of a social need.

  • For decades, scientists have wondered about the origins of intelligence, and have tried

  • to understand why certain animals evolved intelligence, and others did not. The Social

  • Intelligence Hypothesis is the often favored hypothesis for the evolution of complex cognition.

  • It's the idea that intelligence evolved due to the demands of group living, such as maintaining

  • complex and enduring social bonds, deception, cooperation, or social learning. When most

  • of the animals we think of as smart - humans, primates, dogs, dolphins - began living in

  • groups, there became a need for more complex behaviors, and therefore, a bigger, more complex

  • brain.

  • But, this theory can’t explain why intelligence evolved in cephalopods. A different theory

  • must exist for these non-social creatures.

  • You see, our big problem with knowing the development of intelligence is that we know

  • it from the mammals, from the primates, our relatives. So we know that this particular

  • set of conditions sets us up for being intelligent. But then if we have another model, the octopus,

  • then we have to say, Okay, these conditions being part of a social group, they're not

  • necessary for intelligence.

  • Perhaps, the pressures of finding food and evading predation is enough for intelligence

  • to blossom. This is the basis for the Ecological Intelligence Hypothesis, which suggests that

  • complex cognition evolved to meet the challenges associated with predation, foraging, and competitive

  • pressures. And when the octopus lost its shell 140 million years ago, perhaps the pressure

  • of predation was so high that outsmarting their attackers became the only way for it

  • to survive.

  • These two theories are not competing ones, but rather, two explanations for two instances

  • of intelligence on the tree of life.

  • The octopus gives us a rare chance to investigate an alternate intelligence, an alien-like life

  • form here on Earth, giving insight to the origin of our own cognition, and intelligence

  • as a whole. Where we once thought there was only one model for intelligence, we now know

  • that there are at least two. And who is to say how many more there could be, on this

  • earth, or elsewhere?

  • But, despite the distance from us on the evolutionary tree, the octopus still lives inside the same

  • grand experiment as we do. The Earth, the oceans, and the spinning wheels of evolution

  • have crafted us both. They are not so much alien then, as much as a distant, distant

  • relative. And by stepping aside from our human-centric view of intelligence, can we start to clearly

  • see the infinite possibilities of cognition.

  • The story of the modern octopus began so long ago - back when there was no life yet on land.

  • But around this time, 500 million years ago, the oceans had begun to explode with life.

  • This period, called Ordovician, was known for its amazing diversity of invertebrates.

  • And of these invertebrates, the massive, armored cephalopods were king. They dominated the

  • seas for roughly 360 million years. The fossil records show an amazing array of creatures

  • during this time - some we recognize, and some we definitely don’t. Life was thriving,

  • until something stopped nearly all of it in its tracks.

  • To learn more about this period on the early earth, and understand what nearly wiped out

  • all of the animals in the planet’s first mass extinction, you should watchAncient

  • Oceanson Cur