a break for the sea?

Or what about the cephalopod that figured out how to open those child-proof pill bottles?

Which, let's be honest, even adult humans have trouble with those sometimes.

It's fair to say octopuses are smart.

But when we talk about the intelligence of other animals, we tend to fall into the trap

of comparing them to humans -- testing for everything from the size of their brains,

to qualities like emotions or learning abilities.

But octopuses are very different from people, I don't know if you've noticed.

On the evolutionary tree, they are a long way off from us.

And they're probably way more complex than we might realize or understand.

So your brain is in your head.

And so are the brains of other animals we consider intelligent, like dogs, dolphins,

chimps, and crows.

Octopuses have central brains in their heads, as well, and we have some anatomical similarities.

For example, their brains generate similar electrical patterns as vertebrates, and they

seem to have specialized brain areas for things like learning and memory storage.

They also seem to have a dominant, or preferred, eye -- which is an example of lateralization,

similar to the way people are right- and left-handed.

But the weird thing is: about two-thirds of their neurons are in their arms.

Each arm literally has a mind of its own -- to do its own problem solving and act independently,

while the other arms are doing something completely different.

In a 2013 research study, scientists isolated arms from dead octopuses in order to test

those neuronal responses.

And they found the isolated arms recoil from being pinched, or from touching tap water

or acetic acid.

This suggests that they might have some kind of nociceptors -- or special neurons that

sense danger and pain, like ones that make us pull our hand back when touching a hot

stove.

But -- unlike in humans -- their arms can respond to these kind of stimuli without being

attached to a central brain.

Other experiments have found that the severed arms wriggle around, and even grab onto food.

So, anatomically, octopuses are some pretty cool invertebrates.

But what about their behavior?

Octopuses have been observed using tools -- like picking up two coconut halves to use as a

mobile home -- and manipulating objects in a way that looks a lot like playing.

One 1993 study published in the Journal of Comparative Psychology even suggested that

octopuses seem to display distinct personalities -- reacting to food and threats in individual,

but consistent ways.

One octopus might be consistently curious and daring, while another is careful and shy.

Another study, in 2001, seemed to show that young octopuses changed their behavior over

the course of weeks, becoming more alert to danger and learning from their environment.

So octopuses do seem to have some sort of advanced cognition -- learning and changing

their behaviors over time.

Even though we might see a lot of ourselves in the behavior of octopuses, we certainly

didn't get there on the same path.

Our vertebrate evolutionary branch split from the mollusks about 1.2 billion years ago,

so human and octopus intelligence evolved completely separately.

Scientists have lots of different theories to try and explain how humans evolved intelligence

-- and one of them relates to our social lifestyle.

Basically, forming long-lasting relationships could've meant better survival.

But octopuses don't have that specific evolutionary pressure -- they only live for a couple of

years and are almost always alone.

So, how did these creatures evolve their intelligence and central brain -- while other mollusks,

like oysters, didn't?

Well, it might have something to do with the most obvious thing that separates an octopus

from an oyster -- the shell!

At some point in their evolution, the octopus's ancestors probably traded the safety of a

shell for freedom.

Suddenly, they could move around and forage for food, using a variety of hunting skills.

But they also had to to worry about becoming dinner -- which led to all kinds of strategies

to avoid being eaten: like hiding, camouflage, tool use, and speed.

And all that self-preservation requires some sort of intelligence.

The smarter octopuses would've had a better chance of survival.

Octopuses might not look like us, move like us, live like us, or probably even think like

us.

But they have somehow evolved intelligence in ways we're only beginning to understand.

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