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  • One day, 250 years ago

  • a young teacher named Abraham Trembley

  • was walking through a field, and he came to a pond ...

  • ... looked in, and there in the water he saw

  • this thing

  • it was very little with wavy tentacles on top and a tube-like body

  • And just to see what would happen

  • he cut it in half!

  • Much to his surprise instead of dying on the spot ...

  • ... the animal grew back into two full-sized adults.

  • So he did it again.

  • The same thing happened.

  • And again.

  • This animal just wouldn't die!

  • The hydra (that's what its called) has extraordinary powers of regeneration

  • almost as if its built not to die ever

  • which is ridiculous because everything dies, we assume.

  • In science, however, you don't assume - you check!

  • In the 1990's

  • a curious young scientist - Daniel Martinez

  • having heard that hydras go on and on and on

  • decided to do an experiment.

  • He gathered a bunch of hydra from a pond in Long Island, NY

  • put them in some tanks where he could keep an eye on them

  • and he thought,"Alright, I'm going to wait until I see them die naturally."

  • and hydra do die - you take 'em out of water

  • they'll shrivel up

  • but in a natural environment? Nobody knows.

  • Daniel waited.

  • First his hydras had babies.

  • Then a week passed.

  • Then months passed.

  • Meanwhile, Daniel's school year ended.

  • He got a job out west in California.

  • Rather than miss the death of his hydras he put them in a cooler

  • travelled cross country with his brother

  • and everyday wherever he was

  • he fed them, washed them, and he waited.

  • A year passed.

  • Then two years.

  • Three years - still no deaths.

  • Four years out Daniel published a science paper that said hydras apparently never die.

  • Well, what he really said was:

  • "Mortality patterns suggest lack of senescence in hydra."

  • Now you'd think four years is kind of a short term for a claim like this...

  • I mean, a lot of us are past our fourth birthdays and we still expect to die. But here's the thing:

  • There's a well known pattern in nature.

  • The sooner you have babies,

  • the sooner you die.

  • If you're a tiny fly you have your babies quickly

  • after a couple of weeks

  • and you die ... here, after a couple of months

  • If you're a huge elephant you wait thirteen years to have your babies, you live for another 40 or 50 years

  • and then you die right around here.

  • And this is true across the animal kingdom

  • except when it comes to hydra.

  • Remember, hydra have their babies after a couple of days

  • so they should die after say a month.

  • But Dan's hydra had lived for four years when he published his paper

  • and they are still going strong today. They've now lived for more than 8 years.

  • T hat is 100 times their expected life span.

  • That's like an elephant living for 5,000 years.

  • It's like everybody else got the memo that in the end you die

  • but not the hydra.

  • So what's going on?

  • Daniel says - "Here's my theory:"

  • Most animals -- humans and hydras both --

  • begin with a cell, a single cell, and they multiply.

  • In humans, our cells multiply a lot then specialize, age, break down and eventually they wear out

  • and so we die.

  • In a hydra, the cells a) don't specialize much

  • (most hydra cells are embryonic cells,

  • and embryonic cells, like embryos - they're simple and great at staying young)

  • So you can watch them here, moving up the tentacles

  • moving down to the foot

  • and before they have a chance to get much older

  • they flake off

  • to be replaced as you see here by newer cells.

  • Over four years the hydra replaces all its cells -- its entire body -- over 60 times.

  • Every cell in the body is completely new every 20 days.

  • It even looks like a fountain of youth.

  • So.

  • For all intents and purposes, Daniel says, these animals are,

  • and I want to use his word,

  • "Immortal."

One day, 250 years ago

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A2 US hydra die daniel embryonic specialize pond

The Animal That Wouldn't Die (w/Robert Krulwich) | SKUNK BEAR

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    Anbe2623 posted on 2019/12/30
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