Subtitles (181)
0:00Have you ever read an awesome science fact,
0:02only to do a little bit of digging
and learn the source blew things
0:05way out of proportion?
0:06I’m gonna let you behind the
SciShow scenes for a bit.
0:08Our script editors are always on the
hunt for weird and complex science stuff.
0:12Last year, one of them was
reading a book about beavers,
0:15and 150-odd pages in, the
author suddenly mentioned
0:18there’s a type of octopus off the
coast of Australia that, quote,
0:22“builds the equivalent of a walled medieval city.”
0:24Which if true, would probably
make for a good SciShow episode.
0:28As you may suspect, that quote turned out
0:30to be a gross mischaracterization of reality.
0:32And this book is not the only
source to have gotten a bit…
0:36let’s say overenthusiastic…
0:38about what scientists actually uncovered.
0:40But our script editor was
undeterred by this setback.
0:42And with a little more research,
0:44it was clear that these
structures are still super weird,
0:47and reveal just how complex
the octopus lifestyle can be.
0:50So let’s break down what’s really
going down in these octopus cities.
0:57As much as we’d love to animate
an octopus gripping medieval tools
1:00with their many tentacles, and
shouting things like "forsooth!"
1:03and "the devil take thee!",
1:05the real animals behind these
not-actually-cities look like this:
1:09This is Octopus tetricus.
1:11Also known as the gloomy octopus,
1:13because its large, sad eyes
give it a sort of emo vibe.
1:17scientists thought it was a solitary creature,
1:19preferring to hang out in
its bedroom alone listening
1:22to My Chemical Romance and nessa
barrett until three in the morning.
1:25But then, they started discovering
sites where gloomy octopuses gather.
1:28And for context, all of this
is taking place in Jervis Bay,
1:32which is about a two-hour drive
south of Sydney, Australia.
1:35The first site was discovered back in 2009,
1:37and researchers nicknamed it Octopolis.
1:40It’s centered around a 30-centimeter
long Unidentified Sunken Object…
1:45that’s definitely something humans made, but
that’s pretty much all we can say about it.
1:49because the real star of the show
is the horde of scallop shells
1:53and other debris that the
octopuses have collected around it,
1:56and used to construct their dens.
1:59Then in 2016, divers found Octlantis,
2:02a second site just a few hundred
meters away from Octopolis.
2:06Here, gloomy octopuses have
surrounded three patches of rock
2:10with similar piles of debris,
2:11including human things like beer
bottles and lead fishing lures.
2:16The fact that Octlantis wasn’t seeded
2:18by a human-made structure
is actually pretty important
2:21from the science side of things.
2:23Because It shows Octopolis
wasn’t an unnatural fluke
2:26that only happened because of some
accidental outside human influence.
2:30At both of these sites,
2:31researchers have observed
groups of 2 to 15 octopuses
2:35engaging in behaviors like mating,
2:38poking each other with their tentacles,
2:39and kicking other octopuses out of their homes.
2:42A paper from 2022 also reported
2:45that these gloomy octopuses “throw” things.
2:49it kind of looked like it was on purpose.
2:52“Throw” isn’t exactly the right word, though.
2:54It’s kind of more like directed squirting.
2:57Still, not a very nice neighborly thing to do
3:00Ultimately, there’s not much about
these two sites that screams “city”.
3:04But the names Octopolis and Octlantis
3:07sure sound like large metropolitan areas populated
3:10by sentient cephalopods
you’d find in a scifi novel.
3:13The experts who came up with these nicknames
3:15didn’t use them in their research papers,
3:17but they’re eye-catching.
3:18And the SciShow team is well aware
3:20of how important it is to
make a title eye-catching…
3:23Some of the media coverage
about Octopolis and Octlantis
3:26only featured the word “city” in the title,
3:29then switched to a less
suggestive term like “structure”
3:32for the rest of the article.
3:33But let’s all be honest with ourselves,
3:35how often do we only read the
headline, and then keep on scrolling?
3:39There may have also been some confusion generated
3:42by a term the researchers used in their work:
3:44ecological engineering.
3:46To a non-specialist, it might sound
like large construction projects.
3:50If we’re sticking to the non-human sort,
3:52maybe something like a beaver dam.
3:54But it actually has a much broader definition
3:56that includes any type of environmental
modification by a living thing.
4:01The press release announcing the
discovery of Octlantis quoted a researcher
4:05who referred to the octopuses as
“true environmental engineers”.
4:09And a few sources seem to have
extrapolated from this jargon,
4:12and claimed the octopuses also
built fences and created art.
4:16And of course, there were
those medieval walled cities
4:19that got our script editor’s hopes up…
4:21But before we get into what is inarguably
the coolest science story of all time,
4:25we’ve got to keep the lights on, so here’s an ad
4:28This SciShow video is supported by Brilliant:
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5:01To learn for free on Brilliant,
5:02go to brilliant.org/scishow,
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5:16So putting the media frenzy aside,
5:18here’s what scientists have really
said about Octopolis and Octlantis.
5:21The two sites do reveal the gloomy octopus
5:24is way more social than scientists once believed,
5:27and they add to a growing body of
evidence that octopuses in general
5:31are more social than we thought.
5:32That’s a valuable discovery in its own right.
5:34And now that we know these sites exist,
5:36they’ll help researchers study octopus behavior,
5:39and fill the gaps in our knowledge base
5:41about these weird and wonderful creatures.
5:43Which leads me to one major outstanding question:
5:46Did the residents of Octopolis and Octlantis
5:48make a conscious decision
to build their communities?
5:51Scallops are part of the gloomy octopus’s diet,
5:54and waiting to snack until
you’re back inside your den
5:56is safer than out in the middle of nowhere.
5:59So it makes sense that
discarded shells would be found
6:01around a gloomy octopus’s home in large numbers.
6:04The residents of Octopolis and Octlantis
6:06seem to be deliberately
choosing to build their dens
6:09in piles of scallop shells.
6:11But the sites themselves might
have begun as happy accidents.
6:14The experts behind the
Octlantis discovery hypothesize
6:17that the first octopus probably
built a den in the area
6:21because some shells were already present,
6:23and made for a better building
material than sediment.
6:26This may have created a positive feedback process
6:28where the octopus brought
ever more prey back to its den
6:31and unintentionally provided
more building material
6:34as it haphazardly tossed out the trash.
6:36Another octopus may have
eventually moved into the area
6:39to take advantage of that trash,
6:41started doing its own local snacking,
6:43and so on and so forth.
6:45Suddenly, you’ve got a bunch of octopus neighbors
6:47adapting to deal with each other’s presence.
6:50Now, this hypothesis doesn’t
mean there’s no intention
6:52behind what these octopuses are doing.
6:54Some have been observed using inedible objects
6:57like sponges to create a hatch
at the opening of their dens.
7:00They’ve also been observed cleaning their dens,
7:03using jets of water to get rid of unwanted stuff
7:06like broken shells, algae, and silt.
7:08But if you want an octopus city,
7:10you’re gonna need more than a
bunch of individual octopuses
7:13intentionally making and managing their
own homes in the same general area.
7:17Sure, it might be a little bit too much to ask
for an octopus shopping mall or art museum.
7:22But scientists haven’t observed any
evidence of cooperative construction,
7:27or sense of sustained community.
7:29So the main takeaway from Octopolis and Octlantis
7:31isn’t “Oh my gosh the octopuses
are building cities!,”
7:35It’s more like “Oh my gosh the octopuses aren’t
7:38automatically a bunch of
asocial loners after all.”
7:41And they are building cool stuff
7:42These sites show that normally solitary
octopuses are highly adaptive socially,
7:47and willing to congregate if
the environment supports it.
7:49But there are still plenty
of unanswered questions.
7:52Scientists still aren’t sure
what the costs and benefits are
7:55of living a solitary life versus a communal life.
7:58For example, aggressive behavior in
these communal locations has costs.
8:01It uses energy and it may increase the
risk of becoming food for a predator.
8:05So scientists will have to do more research
8:07before they will understand why the
residents of Octopolis and Octlantis
8:11are choosing to stick around
for however long they do.
8:14But in the meantime, we’re excited to see how
Octopolis and Octlantis continue to thrive
8:19And if there’s any updates,
we’ll be sure to let you know
8:21Because after all, there might be a third
8:23or a fourth Octopus City somewhere out there
