Garrison L. Hilliard
2016-06-07 21:12:33 UTC
Electric eels can jump out of the water to attack
USA TODAY NETWORK Mary Bowerman, USA TODAY Network 8:21 a.m. EDT June
7, 2016
New research reveals that electric eels can spring out of the water
and administer powerful electric shocks to would-be predators.
Electric eels will attack large, partially submerged objects by
raising up out of the water and zapping perceived threats, according
to a study published this week in the journal Proceedings of the
National Academy of Sciences.
The research lends credibility to a legendary account by 19th-century
explorer Alexander von Humboldt, who said he witnessed electric eels
leaping from the waters of the Amazon and shocking horses.
Vanderbilt University biologist Kenneth Catania, who lead the study,
said in a statement that many were skeptical of von Humboldts
account. In part, because in the 200-some years since von Humboldt
shared his experience, there have been no similar scientific reports
of eels acting similarly.
The first time I read von Humboldts tale, I thought it was
completely bizarre, said Catania. Why would the eels attack the
horses instead of swimming away?
Catania said he discovered that eels act even more dramatically than
von Humboldt described, by accident, while transferring eels he was
studying from one tank to another.
While using a net with a metal rim handle to transfer the eels, he
noticed that many of the eels stopped trying to dodge the net and
instead went into attack mode, rising out of the water, and plastering
their chins to the handle, all while generating a series of
high-voltage pulses.
Catania notes that luckily he was wearing rubber gloves, so he didnt
get shocked by the eels.
To test what was happening, Catania placed a conductive rod attached
to an aluminum plate partially into the aquarium water, and measured
the strength of the electric pulses the eels produced as they jolted
the object.
Catania found that when an eel was submerged in the water, the power
of its electrical impulse traveled though the water and was much
weaker, but when the eel extended out of the water, the jolt of
electricity was distributed from its chin directly to the believed
threat.
This allows the eels to deliver shocks with a maximum amount of power
to partially submerged land animals that invade their territory,
Catania said. It also allows them to electrify a much larger portion
of the invaders body.
To illustrate just what this tactic can do to a perceived threat,
Catania covered a plastic alligator head with a conductive metal strip
and LED lights.
When you see the LEDs light up, think of them as the endings of pain
nerves being stimulated," Catania said. "That will give you an idea of
how effective these attacks can be."
Catania notes that in the experiment, the eels tended to attack more
often when the water in the tank was low, suggesting that the
"shocking leap" behavior is used to protect themselves during the dry
season in the Amazon, when they are vulnerable.
Follow @MaryBowerman on Twitter.
http://www.usatoday.com/story/tech/nation-now/2016/06/07/electric-eels-jump-water-attack-predators-alexander-von-humboldt-legend/85542740/
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USA TODAY NETWORK Mary Bowerman, USA TODAY Network 8:21 a.m. EDT June
7, 2016
New research reveals that electric eels can spring out of the water
and administer powerful electric shocks to would-be predators.
Electric eels will attack large, partially submerged objects by
raising up out of the water and zapping perceived threats, according
to a study published this week in the journal Proceedings of the
National Academy of Sciences.
The research lends credibility to a legendary account by 19th-century
explorer Alexander von Humboldt, who said he witnessed electric eels
leaping from the waters of the Amazon and shocking horses.
Vanderbilt University biologist Kenneth Catania, who lead the study,
said in a statement that many were skeptical of von Humboldts
account. In part, because in the 200-some years since von Humboldt
shared his experience, there have been no similar scientific reports
of eels acting similarly.
The first time I read von Humboldts tale, I thought it was
completely bizarre, said Catania. Why would the eels attack the
horses instead of swimming away?
Catania said he discovered that eels act even more dramatically than
von Humboldt described, by accident, while transferring eels he was
studying from one tank to another.
While using a net with a metal rim handle to transfer the eels, he
noticed that many of the eels stopped trying to dodge the net and
instead went into attack mode, rising out of the water, and plastering
their chins to the handle, all while generating a series of
high-voltage pulses.
Catania notes that luckily he was wearing rubber gloves, so he didnt
get shocked by the eels.
To test what was happening, Catania placed a conductive rod attached
to an aluminum plate partially into the aquarium water, and measured
the strength of the electric pulses the eels produced as they jolted
the object.
Catania found that when an eel was submerged in the water, the power
of its electrical impulse traveled though the water and was much
weaker, but when the eel extended out of the water, the jolt of
electricity was distributed from its chin directly to the believed
threat.
This allows the eels to deliver shocks with a maximum amount of power
to partially submerged land animals that invade their territory,
Catania said. It also allows them to electrify a much larger portion
of the invaders body.
To illustrate just what this tactic can do to a perceived threat,
Catania covered a plastic alligator head with a conductive metal strip
and LED lights.
When you see the LEDs light up, think of them as the endings of pain
nerves being stimulated," Catania said. "That will give you an idea of
how effective these attacks can be."
Catania notes that in the experiment, the eels tended to attack more
often when the water in the tank was low, suggesting that the
"shocking leap" behavior is used to protect themselves during the dry
season in the Amazon, when they are vulnerable.
Follow @MaryBowerman on Twitter.
http://www.usatoday.com/story/tech/nation-now/2016/06/07/electric-eels-jump-water-attack-predators-alexander-von-humboldt-legend/85542740/
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