Can alligators survive this apex predator? - Kenny Coogan

231,604 views ・ 2023-08-24

TED-Ed


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

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It's 5000 BCE in the verdant swamps of North America,
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and this young deer has no idea it’s being hunted.
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Suddenly, an alligator hurtles out of the water at almost 50 kilometers an hour,
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locking its jaws around its prey
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and swinging wildly in a signature move known as the death roll.
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This deer never stood a chance,
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but then, nothing in this region can compete with this apex predator.
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These alligators easily devour the birds, turtles, and small fish
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living in what’s known today as Everglades National Park.
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But despite ruling the swamp for millennia,
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the last 500 years have brought deadly new predators
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that challenge the alligators’ reign.
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And the origins of these international invaders are just as unexpected
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as their impact on the Everglades.
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We tend to think of swamps as hostile landscapes
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since they’re overflowing with plant and animal life.
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But all this biodiversity makes these environments vital to regional food webs.
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And the Everglades are no exception.
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The park's subtropical climate can support species from around the world,
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and its borders are full of ecotones— transition areas between habitats—
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that connect the region’s freshwater prairies,
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rocky pinelands, mangrove forests, and more.
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Human activity has made the region even more biodiverse,
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developing Florida into a major port
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that welcomes countless human and non-human migrants.
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In the 1500s, Spanish colonizers brought wild boar to the area,
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which quickly multiplied and uprooted the wetlands.
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They devoured alligator eggs and spread European parasites to local panthers.
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Then, in the 1800s, Florida’s shipping industry exploded,
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bringing all manner of new invasive species.
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Brazilian peppertrees blocked out the sun, water hyacinths clogged the rivers,
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and brown anole lizards upset the food chain.
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Alligator populations mostly endured this onslaught,
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but in the late 19th century,
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human intervention kicked things up a notch.
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Government and business officials wanted to turn the Everglades into farmland
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and began building canals to drain the swamp.
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They also planted non-native trees which crowded out the plants
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local birds relied on for food and shelter,
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which in turn limited the alligators’ supply of prey.
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Interventions like this wreaked havoc on the Everglades for decades,
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until a conservationist named Marjory Stoneman Douglas
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finally came to their defense.
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In 1947, Douglas published a landmark book explaining that the Everglades
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were not only a unique and precious ecosystem,
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but that the region’s most fearsome residents were actually vital
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to sustaining it.
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During the wet season,
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alligators are constantly shaping the muddy landscape,
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drawing lines with their bodies
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and digging holes with their snouts, claws, and tails.
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In the dry season,
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these indentations become essential watering holes and firebreaks,
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maintaining and protecting the swamp’s other residents.
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In the wake of Douglas’ book, Everglades National Park was established
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to formally begin protecting the landscape and its scaly stewards.
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But outside the park,
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conditions were brewing for the most dangerous invasion yet.
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Over the next 40 years, the exotic pet trade
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brought parakeets, iguanas, and relatives of piranhas to the region.
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In the 1990s, Burmese pythons became a cheap, popular pet for many Floridians.
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Some snake owners released their pets into the wild when they grew too large.
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But the python population really exploded in 1992
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when a hurricane destroyed a breeding facility
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and released countless snakes into the wild.
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Since then, pythons have been connected to a 90% decrease
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in some local mammal populations,
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decimating the alligators’ food supply.
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And with help from other invasive reptiles like black and white tegus—
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giant lizards who devour alligator eggs—
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these snakes have made a serious play for the top of the local food chain.
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Today, Florida ranks among the regions with the most invasive species
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in the world.
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Some researchers suggest hunting these invaders down,
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while others recommend bringing in yet more creatures to balance the scales,
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such as releasing insects to eat invasive plants.
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It might seem absurd to try solving this problem with more foreign fauna.
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But perhaps a new arrival could fight invaders and feed the alligators—
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giving them the boost they need to reclaim their ancient home.
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