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  • Translator: Joseph Geni Reviewer: Joanna Pietrulewicz

  • Greg Gage: The octopus is a rather strange-looking animal

  • that exhibits amazingly complex behaviors.

  • They have the most impressive nervous system in the entire invertebrate world.

  • They have about a half a billion neurons

  • that are distributed throughout their body,

  • such that two-thirds of the neurons are actually in its legs.

  • Now mix this in with camouflaging cells, jet propulsion and a razor-sharp beak,

  • and you have all the makings of a formidable predator.

  • And then throw in the fact that the octopus is a solitary creature,

  • and suddenly, we have ourselves a real cephalopod fight.

  • (Bell)

  • [DIY Neuroscience]

  • We know that almost all animals fight -- for food, for territory, for mates.

  • The octopus is no different, and knowing their fighting behavior

  • could help us better understand these fascinating creatures

  • and how they interact.

  • My friend Ilya has been observing the classic fighting behavior

  • between California two-spot octopuses.

  • Ilya Chugunov: Most people think that it's "octopi,"

  • but that's actually incorrect.

  • The correct plurals are either "octopuses" or "octopodes"

  • if you want to be very Greek about it.

  • GG: So how do you do your experiment?

  • IC: First, I like to set up the chamber just so it's ready,

  • so I get a jug of water, I aerate it by shaking the jug.

  • It seems that if the water is well-aerated, they're a lot more active.

  • This gives the octopuses some room to breathe.

  • I get the first octopus --

  • Here, buddy. Here, pal.

  • Put it in, set up my GoPro,

  • put the second octopus in, cover it up and leave it alone.

  • (Bell ringing)

  • Rule 1: There's always an aggressor.

  • There's always one octopus on defense, one on offense.

  • Usually the one that's taking up more space, that's more boastful,

  • definitely the aggressor, most likely the winner of the fight.

  • The loser's pretty obvious.

  • They get pushed around, they curl up, hide in a corner.

  • A lot of the time, when there's initial contact,

  • if one of them is too much on the defensive side,

  • the second one will sort of poke at it, grab at its tentacle and see,

  • "Hey, do you want to fight me, do you want to turn around?

  • Do you want to start a wrestling match?"

  • So it'll just poke and run away. Come back, poke and run away.

  • (Bell ringing)

  • Rule 2: Avoid eye contact.

  • When the octopuses come towards each other to begin the fight,

  • they don't actually face each other.

  • They approach sideways.

  • The defensive octopus tries to face away from the attacker

  • until it's the critical moment it knows there's no way to avoid a fight.

  • GG: Really, the one who's waiting to the last moment

  • is the defensive octopus.

  • (Bell ringing)

  • Rule 3: Flash your colors.

  • The aggressor in a fight will quickly and sharply flash bright black on his arms

  • when he's about to initiate a fight.

  • (Bell ringing)

  • GG: Ooh, and already --

  • IC: We're seeing some action.

  • Looks like they've spotted each other.

  • GG: Right. So now he's going to come -- He's approaching, but not directly at him.

  • IC: Yeah, they're like almost completely antiparallel.

  • GG: And then right there --

  • IC: Yeah. They contact, and then their arms clash together.

  • (String music)

  • GG: So we've taken the first steps in understanding fighting in the octopus.

  • And you might be asking yourself: Why does this even matter?

  • Well, these types of curiosity-based research questions can often lead

  • to some unexpected insights and discoveries.

  • We've learned a lot about ourselves from studying marine animals.

  • Squid have taught us about how our neurons communicate,

  • and the horseshoe crab has taught us about how our eyes work.

  • So it's not too far of a stretch to say that some of these behaviors

  • that we're seeing in the California two-spot octopus are similar to ours.

Translator: Joseph Geni Reviewer: Joanna Pietrulewicz

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【TED】How octopuses battle each other | DIY Neuroscience, a TED series

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    林宜悉   に公開 2018 年 09 月 15 日
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