The sneakiest tricksters of the animal kingdom - Eldridge Adams

642,684 views ・ 2018-12-18

TED-Ed


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

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A male firefly glows above a field on a summer’s night,
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emitting a series of enticing flashes.
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He hopes a nearby female will respond with her own lightshow
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and mate with him.
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Sadly for this male,
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it won’t turn out quite the way he plans.
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A female from a different species mimics his pulsing patterns:
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by tricking the male with her promise of partnership,
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she lures him in–
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and turns him into an easy meal.
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He’s been deceived.
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Behavioral biologists have identified three defining hallmarks of deception
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by non-human animals:
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it must mislead the receiver,
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the deceiver must benefit,
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and it can’t simply be an accident.
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In this case we know that the predatory firefly’s signal isn’t an accident
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because she flexibly adjusts her flash pattern
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to match males of different species.
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01:02
Based on this definition,
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where is animal deception seen in nature?
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Camouflage is a good starting point–
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and one of the most familiar examples of animal trickery.
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The leaf-tailed gecko and the octopus fool viewers
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by blending into the surfaces on which they rest.
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Other animals use mimicry to protect themselves.
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Harmless scarlet kingsnakes have evolved red, yellow, and black patterns
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resembling those of the venomous eastern coral snake
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to benefit from the protective warnings these markings convey.
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Even some plants use mimicry:
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there are orchids that look and smell like female wasps to attract hapless males,
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who end up pollinating the plant.
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Some of these animals benefit by having fixed characteristics
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that are evolutionary suited to their environments.
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But in other cases,
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the deceiver seems to anticipate the reactions of other animals
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and to adjust its behavior accordingly.
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Sensing a threat,
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the octopus will rapidly change its colors to match its surroundings.
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Dwarf chameleons color-match their environments more closely
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when they see a bird predator rather than a snake–
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birds, after all, have better color vision.
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One of the more fascinating examples of animal deception
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comes from the fork-tailed drongo.
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This bird sits atop tall trees in the Kalahari Desert,
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surveying the landscape for predators and calling when it senses a threat.
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That sends meerkats, pied babblers, and others dashing for cover.
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But the drongo will also sound a false alarm
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when those other species have captured prey.
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As the meerkats and babblers flee,
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the drongo swoops down to steal their catches.
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This tactic works about half the time–
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and it provides drongos with much of their food.
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There are fewer solid cases
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of animals using signals to trick members of their own species,
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but that happens too.
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Consider the mantis shrimp.
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Like other crustaceans,
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it molts as it grows,
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which leaves its soft body vulnerable to attack.
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But it’s still driven to protect its home against rivals.
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So it has become a masterful bluffer.
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Despite being fragile,
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a newly molted shrimp is actually more likely to threaten intruders,
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spreading the large limbs it usually uses to strike or stab its opponents.
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And that works –
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bluffers are more likely to keep their homes than non-bluffers.
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In its softened condition,
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a mantis shrimp couldn’t withstand a fight–
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which is why we can be confident
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that its behavior is a bluff.
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Biologists have even noticed that its bluffs are tactical:
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newly molted mantis shrimp are more likely to bluff against smaller rivals,
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who are especially likely to be driven away.
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It would seem that instead of just threatening reflexively,
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the mantis shrimp is swiftly gauging the situation and predicting others’ behavior,
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to get the best result.
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So we know that animals can deceive,
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but do they do so with intent?
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That’s a difficult question,
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and many scientists think we'll never be able to answer it.
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We can't observe animals’ internal thoughts.
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But we don’t need to know what an animal is thinking in order to detect deception.
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By watching behavior and its outcomes,
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we learn that animals manipulate predators, prey, and rivals,
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and that their capacity for deception
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can be surprisingly complex.
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