Anacondas explained: How these snakes become the world's largest
October 10, 2018 – Green anacondas, native to South America, are among the world’s largest snakes. The semiaquatic snakes weigh as much as 550 pounds, and can be as long as a school bus. They maintain their massive size by eating prey as large as capybaras and jaguars.
Anacondas have evolved special features to help them swallow their large meals whole. Backwards-pointing teeth help move the prey through the snake’s head and into its body, while a snorkel-like wind pipe allows the snake to breathe.
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NARRATOR: This
intimidating reptile
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is the heaviest snake in the
world, and one of the largest.
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At 30 feet, the anaconda
can grow to be nearly
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the length of a school bus.
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When most people say
anaconda, they're
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referring to the largest of
the four species of anacondas,
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the green anaconda.
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At up to 550 pounds,
that's some serious heft.
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But these massive
snakes have another
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lesser-known characteristic.
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They thrive in water.
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In fact, the name of
the anaconda's genus
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is Eunectes, meaning
good swimmer.
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Eyes and nostrils positioned
on top of their heads
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allow the snakes to remain
almost completely submerged
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as they wait to ambush prey.
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Anacondas aren't
venomous snakes.
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They are constrictors.
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In seconds, anacondas
wrap around their prey,
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constricting tighter and
tighter until the blood
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supply is cut off.
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Like other
constrictors, anacondas
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sense when their prey's
heart has stopped,
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and only then release
their grip and begin
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to eat their meal whole.
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Anacondas swallow
their prey whole
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with the help of both
stretchy ligaments
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and mobile joints
in their mouths.
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In the middle of the
anaconda's upper jaw
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are two rows of
backward-pointing teeth.
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These teeth can
move independently,
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biting into prey, and
helping move the snake's
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head up and over its meal.
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But eating a meal in this
way creates a unique problem.
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With its mouth stretched so
tightly around the animal,
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the anaconda can't breathe
as it normally would.
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But through evolution, the snake
has developed a clever trick
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to deal with that.
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The windpipe, normally
located deep in the throat,
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gets pushed up and out of the
mouth, acting like a snorkel
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and allowing the
anaconda to breathe.
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And breathing
normally is especially
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important, given
the time it takes
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an Anaconda to finish its meal.
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A green anaconda
can take many hours
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to swallow a meal, and more
than a week to digest it.
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Large prey such as
capybara and even jaguar
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provide the anacondas
the energy they
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need to maintain their size.
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Once consumed, the Anaconda
will not need to eat
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again for weeks or months.
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And when 30% of the
female's body weight
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is used for
reproduction, their prey
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are also vital to the
female anaconda's survival.
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Unlike most of the
world's snakes,
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anacondas don't lay eggs.
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Instead, the young hatch while
still inside of their mother,
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who will later give live birth.
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After seven months of
fasting during pregnancy,
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the anaconda mom takes in
some of the nutrients she lost
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by feasting on her eggs
that never developed,
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and any of her young
which were not born alive.
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With an average of 20
to 40 babies per brood,
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it could be hard to
keep them all in line.
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For the anaconda, however,
this isn't a problem.
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Immediately after being
born, the anaconda
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babies are able to
make it on their own
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without the help of mom.
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Born with the instincts to
hunt and fend for themselves,
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baby anacondas have the innate
skills to survive and become
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the next giants of South
America's Amazonian waterways
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and jungles.