Why did it take so long to find giant squids? - Anna Rothschild

21,417 views ・ 2024-09-26

TED-Ed


Please double-click on the English subtitles below to play the video.

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In 1873, two fishermen off the coast of Newfoundland
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glimpsed what they thought was a submerged shipwreck.
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But when they probed the mass, it moved—
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and huge serpentine appendages soon besieged their boat.
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One fisherman took an axe to the animal, and it disappeared in a cloud of ink.
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What remained were two long limbs—
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definitive evidence in a collection of clues that would only continue to grow.
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Over time, it became clear that giant squids were more than mythical monsters.
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People found sizable specimens washed ashore,
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caught in nets, and at the sea’s surface,
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and observed sperm whales with sucker-shaped scars
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and large beaks in their stomachs.
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But it wasn’t until recent decades that scientists actually found
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living giant squids in their natural habitat.
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So, what do we really know about these creatures?
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Well, interestingly, one thing we've gathered is that they might not even be
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the biggest squids out there.
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There are hundreds of squid species inhabiting almost all parts of the ocean,
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ranging from the size of a thumbnail
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to more than seven times the length of a human.
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All squids are carnivores and share the same basic body plan,
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including a muscular mantle that covers their internal organs, a sharp beak,
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eight arms, and two tentacles specialized for capturing prey.
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The smallest squids eat things like tiny shrimp,
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while larger ones can feast on fish using their powerful beaks.
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The Humboldt squid’s bite force, for example,
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is strong enough to shatter Kevlar plates.
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And the suckers on the giant squid’s long, clubbed tentacles
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are encircled by sharp, teeth-like protrusions
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that help them grip prey like deep sea fish and other squids.
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Giant squids live in the cold, dark, high pressure twilight zone.
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It's extremely unlikely you'd ever encounter one,
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since you'd be very out of your depth down there.
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We don’t know exactly why giant squids are so big—
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but the phenomenon fits with a pattern of deep-sea gigantism,
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where certain deep-sea species dwarf their shallow-living relatives.
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Perhaps because food down there is scarce,
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large animals that can cover more ground and store more food are favored.
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Giant squids’ size could also give them an anti-predator advantage,
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while the deep’s cool temperatures help them manage their metabolic rates.
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Innovations over the past 150 years—
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from dredges and bathyspheres
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to untethered and remotely operated submersibles—
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have enabled peeks into the deep.
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And yet, it wasn’t until 2004
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that researchers actually saw a giant squid in its natural habitat.
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Then finally, in 2012, scientists lured a giant squid and got it on video.
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They used a stealth camera system fitted with a device
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mimicking a bioluminescent jellyfish under attack.
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The system had no thrusters, keeping it unobtrusively quiet.
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And it only projected beams of red light— undetectable to most deep-sea dwellers.
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Both encounters revealed that giant squids are not sit-and-wait predators,
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as previously suspected.
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Instead, they’re active hunters that use their basketball-sized eyes
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to stalk their prey
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before projecting their tentacles and snatching animals up to 10 meters away.
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But many questions still stand.
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We know sperm whales eat giant squids,
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but it’s unclear how fierce the fight is
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and if the squids ever stand much of a chance of escaping.
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Extrapolating off the number of giant squid beaks in whale bellies,
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one estimate placed the global giant squid population at around 4 million.
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It seems they mate when a male injects sperm packets into a female’s arm—
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but exactly how they find each other and what happens after are uncertain.
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Giant squids are globally distributed,
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but they’re mostly missing from the planet’s polar regions,
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one of which happens to be where another humongous squid species lurks:
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the elusive colossal squid.
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Far fewer specimens have been collected,
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and they’ve yet to be seen or documented in their habitat.
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But we know they’re from a completely different family than giant squid—
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evidence that gigantism independently evolved more than once among squids.
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Their limbs are shorter than giant squids’,
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but their mantles are larger, making them up to twice as heavy.
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And unlike the giant squid’s toothy tentacles,
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colossal squids have hooked, swiveling sucker barbs.
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Much remains mysterious about these animals.
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But we know they’re down there,
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guarding their secrets in the deep, dark sea.
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