July 31, 2026 • 13 mins
These marine invertebrates can solve puzzles, use tools, and camouflage themselves by changing their very skin -- yet they live only three to five years, and die after mating. Learn more about octopuses in today's episode of BrainStuff, based on these articles: https://animals.howstuffworks.com/marine-life/octopus.htm/printable; https://animals.howstuffworks.com/marine-life/why-is-octopus-blood-blue.htm
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Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio. Hey, Brainstuff, Lauren
Bobblebaum here. But we humans are lucky that our sexual
dimorphism is relatively mild. It certainly makes city planning easier.
Consider the blanket octopus. A full grown male of the
(00:22):
species is less than an inch long, only a couple
of centimeters, and weighs less than a gram. The females
can reach more than six feet or two meters in
length and weigh one hundred pounds. That's forty five kilos.
That means a female blanket octopus is some forty thousand
times heavier than a male. In human terms, it would
(00:43):
be like a man walking down the street with a
woman who is four times the size of the Statue
of Liberty, or a woman ringing up an order for
a man the size of a beetle. Luckily, for the
male blanket octopus, a mating is not a full contact sport.
He has a modified arm that contains long rows of sperm.
(01:03):
He simply tears off this arm and politely hands it
to his mammoth mate, who then saves it for later use.
These males have also been known to rip off the
venomous tentacles of the Portuguese man O war and wield
them as makeshift swords to ward off predators. This octopus
is immune to the man o war's sting. And this
(01:24):
is just one fascinating example of the octopod order, which
contains over three hundred species, ranging in size from the
quarter gram male blanket octopus to the six hundred pound
plus giant Pacific octopus that's at least two hundred and
seventy kilos. These invertebrates live only a few years, but
they're seriously smart. They can camouflage themselves, solve puzzles, use tools,
(01:49):
and even be sassy. Today, let's talk about octopuses, and yes,
that is the scientifically preferred plural. The octopus belongs to
the mollusk phylum, alongside slimy next of kin like clams, snails,
and slugs. Within the phylum, octopuses are in the cephalopod class,
(02:11):
which originated some six hundred million years ago and includes
other advanced animals like squid and cuttlefish, but octopuses have
evolved the most. While other cephalopods sport some form of
inner or outer shell like their mollusc relatives, most octopuses
have none. The word cephalopod means head footed. These animal's
(02:33):
arms branch directly off of their heads. Some cephalopods have
tentacles as well as arms, but the octopus manages just
fine with the eight sucker studded arms it uses for
practically everything, eating, moving, hunting, tasting, and mating. There are
actually two suborders of octopus, the better known inserate and
(02:54):
the more mysterious sirate. Serrate octopuses are named for the
pairs of ccilia like strand along the suckers on their arms.
They tend to live in deep cold water and don't
adjust well to other conditions, meaning they're harder to study,
though we've learned a lot about some species, like the
dumbo octopus in recent years. Seriat octopuses do have a
(03:15):
bit of an internal cartilage like shell. Both types of
octopus will have a mouth at the center of its arms,
and its doughnut shaped brain will sit just behind that,
wrapped around the animal's esophagus sort of in the center
of its body. That's where its two eyes are as well.
The bulbous head of an octopus is actually what's called
(03:36):
its mantle, a strongly muscled structure that protects the other
organs its gills hearts. It has three hearts, digestive system
and reproductive glands. Those three hearts come in handy because
octopuses are adapted to survive in extreme temperatures and low
oxygen environments. To cope, an octopus maintains a constant high
(03:58):
blood pressure. Two of its hearts pump oxygen rich blood
through the gills, while the third circulates it through the
rest of the body. That blood is blue in color
because it's copper based, not iron based like ours, which
also makes it better at transporting oxygen in low temperatures.
An octopus will also have a funnel, sometimes called a siphon,
(04:20):
which is a tubular opening near the base of the
mantle that serves as a jetway for water used for
quick movement. Lacking a protective outer shell, the octopus has
a startling array of defense mechanisms. They are masters of disguise.
Cells in their skin called chromatophores, tens of thousands of
them let them change color. These pigmented cells each contain
(04:45):
three sacks of color and is surrounded by muscles that
change how the pigment is displayed by relaxing or contracting
it's sort of like a colorful design printed on a balloon.
When the balloon is relaxed and uninflated, the design and
its colors are smoothed and hidden. But when you stretch
(05:05):
the balloon out by blowing it up, the colors become apparent,
and you might be able to reveal different colors by
expanding different parts of the balloon. The animal's nervous system
can control each chromatophor independently, meaning color displays can be
highly complex and quick. An octopus can change its appearance
in less than a second. Also, areas on the skin
(05:29):
called papilli can change size and texture from flat to
bumpy to spiky to let the animal blend in with
coral rocks, sand seaweed, and other stuff. The mimic octopus
can even use color, shape, and movement to impersonate other animals.
For example, it'll travel in a long, flatfish shape like
(05:50):
the venomous banded soul, or wave an arm like a
banded sea snake to make predators think twice about attacking
and insert. Octopusses have another getaway mechanism, ink. The ink
sack is located near the digestive system, and when necessary,
the octopus can eject black ink out of the sack,
(06:11):
along with the burst of water from its funnel, either
in little blobs that serve as decoys, or in one
bit mass like a smoke bomb, to obscure a quick getaway.
The ink can also contain a compound that impairs smell
and taste, to further confuse predators. Octopuses have excellent senses
of sight and taste, partially because they have lots of
(06:34):
processing power. An octopus's brain is proportionally larger than any
other invertebrate, and smaller only than birds and mammals. The
average octopus has as many neurons as a dog. Its
central brain is only part of the story, though, Three
fifths of the octopus's nerves are distributed throughout its arms
(06:54):
to help it taste, touch, and move around its environment.
Octopus arms are incredibly strong and flexible. Octopods have been
known to wrestle sharks and break through plexiglass, and without
all those pesky bones and joints that limit our movement,
the arms have an almost infinite range of motion, and
(07:15):
octopus arms have minds of their own. Literally, each has
a cluster of nerve cells called a ganglion that works
as a mini brain and allows the arm to act independently,
though the central brain can take over. Our researchers think
the brain can give an arm an assignment and then
not have to think about it again unless something gets weird,
(07:37):
like maybe the arm moves out of the water where
it can no longer taste prey, so the octopus has
to use its vision to guide the arm further. Next step,
let's talk about octopus behavior. But first let's take a
quick break for a word from our sponsors, and we're back.
(07:58):
Thank you sponsors. Okay. Octopuses tend to spend much of
their lives solitary in a den, leaving at night to hunt.
An octopus might find a suitable den in a crevice
or even a discarded bottle, or make one from objects
like shells. When they do venture out, octopuses have a
(08:19):
couple of ways to get around. If it needs to
make a quick escape, it can jet away by taking
water in through its mantle, sealing that water off, and
then expelling it forcefully through its funnel. They've been clocked
it up to twenty five miles an hour. That's forty
kilometers an hour. Seriate Octopuses are less prolific at jetting,
(08:39):
but they have a pair of fins coming off of
their mantle that they can flap to move around. However,
many octopuses prefer to walk along the seafloor with help
from those rows of suckers on the underside of each arm.
Each sucker has up to ten thousand sensory neurons, so
the octopus can learn a lot about its surroundings this
(08:59):
way and maybe chance upon a meal. Those long, flexible
arms can reach into nooks after tasty crabs and clams,
and their soft bodies are able to squeeze through tiny
spaces after small fish. Octopuses don't have teeth as such
to eat with, but they do have a hard, retractable
beak similar in shape to a parrot's that can tear
(09:22):
apart flesh or pry open shells. Behind the beak is
the radula, which is a sort of barbed tongue the
octopus can use to scrape meat out of a shell.
It also has what's called a salivary papilla coming off
of its salivary gland. This is a sort of secondary
tongue with more toothy barbs that can drill through shell.
(09:44):
The octopuses saliva can erode shell, and we can pray.
In spite of being so clever and well built, octopuses
only live an average of three to five years. Most
will mate only once in their life and die soon afterwards,
the male after a few months and the female after
her eggs hatch. Not all of them detach an arm
(10:06):
in the mating process, though the males do tend to
have a modified arm for holding sperm. Either way, once
the female receives sperm, she lays her eggs or applies
it to her laid eggs if she's been saving a
stray arm for the occasion. The female often cares meticulously
for her eggs until they hatch, blowing water across them
(10:27):
to keep them clean and protecting them from predators. The
eggs might incubate from two to ten months or more,
depending on the species and water temperature. Sometimes the female
will forego eating to protect them, so once they hatch,
there on their own. If it manages to survive predation,
(10:47):
a young octopus may eat enough to increase its weight
by five percent every day. After all, it doesn't have
time to lose. And let's talk about those smarts. Octopuses
are capable of thought, typically only observed in primates, and
select other animals like crows in the wild. The giant
(11:08):
Pacific octopus has been seen stealing crabs caught in traps
by human fissures before the fissures can pull in their hull.
The Pacific striped octopus uses a goatchia to catch shrimp.
It'll sneak an arm around to poke the shrimp from
one side, awaiting in the opposite direction to grab the
shrimp when it darts away. The veined octopus is known
(11:30):
to collect coconut shells and seashells, clean them off with
jets of water, and carry them elsewhere to assemble a shelter.
In captivity, octopuses have learned to solve mazes and puzzles
and complete tasks to receive tasty rewards. They've been known
to crawl out of their aquariums to sneak food from
(11:50):
bins or other tanks, and then return to their home
tank unassisted. Some can crawl across dry land for a
limited period of time. Octopuses can recognize different humans faces
and will react differently to them. There is an anecdote
out of a University in New Zealand, where an octopus
apparently took umbrage to one of the members of the
(12:12):
staff and would squirt water at her every time she
passed the tank. In another incident out of Pennsylvania, a
researcher attempted to feed slightly stale squid to the octopuses
in her lab, and one sent her a clear message.
It made eye contact and used one arm to shove
the squid down a nearby drain, effectively communicating that stale
(12:34):
food would be discarded rather than eaten. Any animal that's
smart enough to be a little rude is definitely impressive.
The researchers are even looking into how we humans can
mimic some of octopus's superpowers to build everything from better
camouflage materials to soft, squishy robots. Today's episode based on
(13:00):
the articles how Octopuses Work by Jennifer Horton and why
is Octopus Blood Blue? Written by Lareel Dove on HowStuffWorks
dot Com. A Brainstuff is production of iHeartRadio in partnership
with HowStuffWorks dot Com and is produced by Tyler Klang.
For more podcasts from my heart Radio, visit the iHeartRadio
app Apple podcasts, or wherever you listen to your favorite shows.
Welcome to Brainstuff, a production of iHeartRadio. Hey, Brainstuff, Lauren
Bobblebaum here. But we humans are lucky that our sexual
dimorphism is relatively mild. It certainly makes city planning easier.
Consider the blanket octopus. A full grown male of the
(00:22):
species is less than an inch long, only a couple
of centimeters, and weighs less than a gram. The females
can reach more than six feet or two meters in
length and weigh one hundred pounds. That's forty five kilos.
That means a female blanket octopus is some forty thousand
times heavier than a male. In human terms, it would
(00:43):
be like a man walking down the street with a
woman who is four times the size of the Statue
of Liberty, or a woman ringing up an order for
a man the size of a beetle. Luckily, for the
male blanket octopus, a mating is not a full contact sport.
He has a modified arm that contains long rows of sperm.
(01:03):
He simply tears off this arm and politely hands it
to his mammoth mate, who then saves it for later use.
These males have also been known to rip off the
venomous tentacles of the Portuguese man O war and wield
them as makeshift swords to ward off predators. This octopus
is immune to the man o war's sting. And this
(01:24):
is just one fascinating example of the octopod order, which
contains over three hundred species, ranging in size from the
quarter gram male blanket octopus to the six hundred pound
plus giant Pacific octopus that's at least two hundred and
seventy kilos. These invertebrates live only a few years, but
they're seriously smart. They can camouflage themselves, solve puzzles, use tools,
(01:49):
and even be sassy. Today, let's talk about octopuses, and yes,
that is the scientifically preferred plural. The octopus belongs to
the mollusk phylum, alongside slimy next of kin like clams, snails,
and slugs. Within the phylum, octopuses are in the cephalopod class,
(02:11):
which originated some six hundred million years ago and includes
other advanced animals like squid and cuttlefish, but octopuses have
evolved the most. While other cephalopods sport some form of
inner or outer shell like their mollusc relatives, most octopuses
have none. The word cephalopod means head footed. These animal's
(02:33):
arms branch directly off of their heads. Some cephalopods have
tentacles as well as arms, but the octopus manages just
fine with the eight sucker studded arms it uses for
practically everything, eating, moving, hunting, tasting, and mating. There are
actually two suborders of octopus, the better known inserate and
(02:54):
the more mysterious sirate. Serrate octopuses are named for the
pairs of ccilia like strand along the suckers on their arms.
They tend to live in deep cold water and don't
adjust well to other conditions, meaning they're harder to study,
though we've learned a lot about some species, like the
dumbo octopus in recent years. Seriat octopuses do have a
(03:15):
bit of an internal cartilage like shell. Both types of
octopus will have a mouth at the center of its arms,
and its doughnut shaped brain will sit just behind that,
wrapped around the animal's esophagus sort of in the center
of its body. That's where its two eyes are as well.
The bulbous head of an octopus is actually what's called
(03:36):
its mantle, a strongly muscled structure that protects the other
organs its gills hearts. It has three hearts, digestive system
and reproductive glands. Those three hearts come in handy because
octopuses are adapted to survive in extreme temperatures and low
oxygen environments. To cope, an octopus maintains a constant high
(03:58):
blood pressure. Two of its hearts pump oxygen rich blood
through the gills, while the third circulates it through the
rest of the body. That blood is blue in color
because it's copper based, not iron based like ours, which
also makes it better at transporting oxygen in low temperatures.
An octopus will also have a funnel, sometimes called a siphon,
(04:20):
which is a tubular opening near the base of the
mantle that serves as a jetway for water used for
quick movement. Lacking a protective outer shell, the octopus has
a startling array of defense mechanisms. They are masters of disguise.
Cells in their skin called chromatophores, tens of thousands of
them let them change color. These pigmented cells each contain
(04:45):
three sacks of color and is surrounded by muscles that
change how the pigment is displayed by relaxing or contracting
it's sort of like a colorful design printed on a balloon.
When the balloon is relaxed and uninflated, the design and
its colors are smoothed and hidden. But when you stretch
(05:05):
the balloon out by blowing it up, the colors become apparent,
and you might be able to reveal different colors by
expanding different parts of the balloon. The animal's nervous system
can control each chromatophor independently, meaning color displays can be
highly complex and quick. An octopus can change its appearance
in less than a second. Also, areas on the skin
(05:29):
called papilli can change size and texture from flat to
bumpy to spiky to let the animal blend in with
coral rocks, sand seaweed, and other stuff. The mimic octopus
can even use color, shape, and movement to impersonate other animals.
For example, it'll travel in a long, flatfish shape like
(05:50):
the venomous banded soul, or wave an arm like a
banded sea snake to make predators think twice about attacking
and insert. Octopusses have another getaway mechanism, ink. The ink
sack is located near the digestive system, and when necessary,
the octopus can eject black ink out of the sack,
(06:11):
along with the burst of water from its funnel, either
in little blobs that serve as decoys, or in one
bit mass like a smoke bomb, to obscure a quick getaway.
The ink can also contain a compound that impairs smell
and taste, to further confuse predators. Octopuses have excellent senses
of sight and taste, partially because they have lots of
(06:34):
processing power. An octopus's brain is proportionally larger than any
other invertebrate, and smaller only than birds and mammals. The
average octopus has as many neurons as a dog. Its
central brain is only part of the story, though, Three
fifths of the octopus's nerves are distributed throughout its arms
(06:54):
to help it taste, touch, and move around its environment.
Octopus arms are incredibly strong and flexible. Octopods have been
known to wrestle sharks and break through plexiglass, and without
all those pesky bones and joints that limit our movement,
the arms have an almost infinite range of motion, and
(07:15):
octopus arms have minds of their own. Literally, each has
a cluster of nerve cells called a ganglion that works
as a mini brain and allows the arm to act independently,
though the central brain can take over. Our researchers think
the brain can give an arm an assignment and then
not have to think about it again unless something gets weird,
(07:37):
like maybe the arm moves out of the water where
it can no longer taste prey, so the octopus has
to use its vision to guide the arm further. Next step,
let's talk about octopus behavior. But first let's take a
quick break for a word from our sponsors, and we're back.
(07:58):
Thank you sponsors. Okay. Octopuses tend to spend much of
their lives solitary in a den, leaving at night to hunt.
An octopus might find a suitable den in a crevice
or even a discarded bottle, or make one from objects
like shells. When they do venture out, octopuses have a
(08:19):
couple of ways to get around. If it needs to
make a quick escape, it can jet away by taking
water in through its mantle, sealing that water off, and
then expelling it forcefully through its funnel. They've been clocked
it up to twenty five miles an hour. That's forty
kilometers an hour. Seriate Octopuses are less prolific at jetting,
(08:39):
but they have a pair of fins coming off of
their mantle that they can flap to move around. However,
many octopuses prefer to walk along the seafloor with help
from those rows of suckers on the underside of each arm.
Each sucker has up to ten thousand sensory neurons, so
the octopus can learn a lot about its surroundings this
(08:59):
way and maybe chance upon a meal. Those long, flexible
arms can reach into nooks after tasty crabs and clams,
and their soft bodies are able to squeeze through tiny
spaces after small fish. Octopuses don't have teeth as such
to eat with, but they do have a hard, retractable
beak similar in shape to a parrot's that can tear
(09:22):
apart flesh or pry open shells. Behind the beak is
the radula, which is a sort of barbed tongue the
octopus can use to scrape meat out of a shell.
It also has what's called a salivary papilla coming off
of its salivary gland. This is a sort of secondary
tongue with more toothy barbs that can drill through shell.
(09:44):
The octopuses saliva can erode shell, and we can pray.
In spite of being so clever and well built, octopuses
only live an average of three to five years. Most
will mate only once in their life and die soon afterwards,
the male after a few months and the female after
her eggs hatch. Not all of them detach an arm
(10:06):
in the mating process, though the males do tend to
have a modified arm for holding sperm. Either way, once
the female receives sperm, she lays her eggs or applies
it to her laid eggs if she's been saving a
stray arm for the occasion. The female often cares meticulously
for her eggs until they hatch, blowing water across them
(10:27):
to keep them clean and protecting them from predators. The
eggs might incubate from two to ten months or more,
depending on the species and water temperature. Sometimes the female
will forego eating to protect them, so once they hatch,
there on their own. If it manages to survive predation,
(10:47):
a young octopus may eat enough to increase its weight
by five percent every day. After all, it doesn't have
time to lose. And let's talk about those smarts. Octopuses
are capable of thought, typically only observed in primates, and
select other animals like crows in the wild. The giant
(11:08):
Pacific octopus has been seen stealing crabs caught in traps
by human fissures before the fissures can pull in their hull.
The Pacific striped octopus uses a goatchia to catch shrimp.
It'll sneak an arm around to poke the shrimp from
one side, awaiting in the opposite direction to grab the
shrimp when it darts away. The veined octopus is known
(11:30):
to collect coconut shells and seashells, clean them off with
jets of water, and carry them elsewhere to assemble a shelter.
In captivity, octopuses have learned to solve mazes and puzzles
and complete tasks to receive tasty rewards. They've been known
to crawl out of their aquariums to sneak food from
(11:50):
bins or other tanks, and then return to their home
tank unassisted. Some can crawl across dry land for a
limited period of time. Octopuses can recognize different humans faces
and will react differently to them. There is an anecdote
out of a University in New Zealand, where an octopus
apparently took umbrage to one of the members of the
(12:12):
staff and would squirt water at her every time she
passed the tank. In another incident out of Pennsylvania, a
researcher attempted to feed slightly stale squid to the octopuses
in her lab, and one sent her a clear message.
It made eye contact and used one arm to shove
the squid down a nearby drain, effectively communicating that stale
(12:34):
food would be discarded rather than eaten. Any animal that's
smart enough to be a little rude is definitely impressive.
The researchers are even looking into how we humans can
mimic some of octopus's superpowers to build everything from better
camouflage materials to soft, squishy robots. Today's episode based on
(13:00):
the articles how Octopuses Work by Jennifer Horton and why
is Octopus Blood Blue? Written by Lareel Dove on HowStuffWorks
dot Com. A Brainstuff is production of iHeartRadio in partnership
with HowStuffWorks dot Com and is produced by Tyler Klang.
For more podcasts from my heart Radio, visit the iHeartRadio
app Apple podcasts, or wherever you listen to your favorite shows.
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