Vultures: The acid-puking, plague-busting heroes of the ecosystem - Kenny Coogan

1,480,112 views ・ 2020-02-24

TED-Ed


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

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In the grasslands of Mauritania,
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a gazelle suffering from tuberculosis takes its last breath.
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Collapsing near a small pool,
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the animal’s corpse threatens to infect the water.
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But for the desert’s cleanup crew, this body isn’t a problem: it’s a feast.
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Weighing up to 10 kilograms
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and possessing a wingspan of nearly 3 meters,
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the lappet-faced vulture is the undisputed king of the carcass.
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This bird’s powerful beak and strong neck
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easily tear through tough hide and muscle tissue,
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opening entry points for weaker vultures to dig in.
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This colossal competition is too dangerous for the tiny Egyptian vulture.
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With a wingspan of only 180 centimeters,
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this vulture migrated to Africa from his family nest in Portugal,
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using thermal updrafts to stay aloft for hours at a time.
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But upon arrival, he finds himself near the bottom of the pecking order.
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Fortunately, what he lacks in size, he makes up for in intelligence.
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A short distance away, he spots an unguarded ostrich nest,
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full of immense, but impenetrable eggs.
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Using a large rock, he smashes one open for a well-earned meal—
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though he’ll circle back to the gazelle once the larger birds are gone.
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High above the commotion are Ruppell’s Griffon vultures.
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Soaring at an altitude of over 11,000 meters,
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these birds fly higher than any other animal.
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At this height, they can’t see individual carcasses.
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But the sight of their fellow vultures guides them to the feeding.
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Their featherless heads help them regulate
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the sudden rise in temperature as they descend—
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and keep them clean as they tear into the decaying gazelle.
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The carcass is stripped clean in hours,
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well before the rotting meat infects the water supply.
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And the tuberculosis doesn’t stand a chance at infecting the vultures.
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These birds have evolved the lowest gastric pH in the animal kingdom,
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allowing them to digest diseased carrion and waste without becoming sick.
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In fact, species like the mountain-dwelling bearded vulture
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have stomachs so acidic,
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they can digest most bones in just 24 hours.
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This adaptation helps smaller vultures supplement their diet with dung,
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while larger vultures can consume diseased meat up to 3 days old.
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Their acidic stomachs protect them from living animals too:
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their rancid vomit scares off most predators.
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These stomachs of steel are essential to removing pathogens like cholera,
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anthrax, and rabies from the African ecosystem.
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But while vultures can easily digest natural waste,
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man-made chemicals are another story.
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Diclofenac, a common veterinary drug used to treat cattle in India,
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is fatal to vultures.
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And because local religious beliefs prohibit eating beef,
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scavengers often consume cattle carcasses.
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Since the 1990s, the drug,
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along with threats from electricity pylons and habitat loss,
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has contributed to a 95% decline in the region’s vulture population.
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In nearby Africa, poachers intentionally poison carcasses
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to prevent the birds’ presence from alerting authorities to their location.
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One poisoned carcass can kill over 500 vultures.
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Today, more than 50% of all vulture species are endangered.
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In regions where vultures have gone extinct,
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corpses take three times longer to decay.
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These carcasses contaminate drinking water,
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while feral dogs and rats carry the diseases into human communities.
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The Asian and African Vulture Crisis has led to an epidemic of rabies in India,
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where infections kill roughly 20,000 people each year.
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Fortunately, some communities have already realized how important vultures are.
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Conservationists have successfully banned drugs like Diclofenac,
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while other researchers are working to repopulate vulture communities
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through breeding programs.
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Some regions have even opened vulture restaurants
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where farmers safely dispose of drug-free livestock.
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With help, vultures will be able to continue their role
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conserving the health of our planet— transforming death and decay into life.
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