What is the oldest animal?
What is the oldest animal? This undated photo made available by Julius Nielsen on Aug. 11, 2016 shows a Greenland shark in the icy waters of Disko Bay, western Greenland. (Julius Nielsen via AP)
What is the oldest animal?
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In the cold waters of the Arctic, a denizen of the deep lurked for centuries. Now scientists calculate that this female Greenland shark was the Earth's oldest living animal with a backbone.
They estimated that the gray shark, part of the species named after Greenland, was born in the icy waters roughly 400 years ago, and died only recently. That conclusion puts the entire species at the top of the longevity list.
Using a novel dating technique, an international team of biologists and physicists estimated the age of 28 dead female Greenland sharks based on tissue in their eyes. Eight of the sharks were probably 200 years or older and two likely date back more than three centuries, according to a study published in the journal Science.
Until now, that record holder was a bowhead whale that hit 211 years old, according to study lead author Julius Nielsen and AnAge, an animal longevity database.
The oldest of the Greenland sharks examined was nearly 16.5-feet long and estimated to be 392 years old when it was caught around four years ago. But that calculation comes with a huge margin of error, plus or minus 120 years, due to the newness of the dating technique, said Nielsen, a marine biologist at the University of Copenhagen.
That means the shark was probably born sometime between 1500 and 1740 with the most likely birth year 1620.
"It's an estimate. It's not a determination," Nielsen said. "It is the best we can do."
Even at the lowest end of the margin error, the shark would have been 272 years old when it died, and still would be the longest-living animal with a backbone, Nielsen said. Other experts agreed.
Joao Pedro Magalhaes, a University of Liverpool aging researcher, said because the study is based on an indirect measurement, he wouldn't necessarily concentrate on exact numbers, especially when they exceed 400 years, where the upper end of the margin of error goes.
"But the study is convincing enough for us to say that these animals live way longer than human beings and possibly longer than any other vertebrate," said Magalhaes, who runs the longevity database and wasn't part of Nielsen's team.
Some animals without backbones live longer. An ocean quahog, a clam, lived 507 years, and two different types of sponges are said to survive for 15,000 and 1,500 years.
While not surprised that Greenland sharks live a long time, "I'm really shocked by the magnitude of that longevity," wrote Christopher Lowe, director of the shark lab at California State University Long Beach. He wasn't part of the study, but praised it as creative and compelling.
Greenland sharks love cold water, preferring temperatures near freezing, and are all over the Arctic. The cold water and the slow metabolism that comes with it might have something to do with their long lives, Nielsen said. Lowe, in an email, said "the rule of thumb is deep and cold = old when it comes to fishes."
"I don't know why they get as old, but I hope someone will find out," Nielsen said.
For the age estimates, he uses a complex and indirect system that combines chemical tracking, mathematical modeling and growth measurements. He focuses on the shark eye lens. Those form while the shark is still developing inside the mother's uterus and measures of carbon in them won't change after birth, so it gives a good, rough sense of when the shark was born.
National Oceanic and Atmospheric Administration shark expert Allen Andrews said the dating method "is novel and is likely robust" but he said there are still a number of uncertainties.

Source URL: https://www.tweentribune.com/article/teen/what-oldest-animal/

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Why do cold temperatures promote longevity?
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  • emmab-cel
    8/24/2016 - 09:59 a.m.

    WOW! I didn't even know this shark existed. Its amazing to think about how long they have been alive and what they must have been threw to live that long. I hope in the future we can find out a lot more about them and what makes them live so long.

  • pilarj-cel
    8/24/2016 - 11:27 a.m.

    I thought that this article was pretty cool. I don't have the strongest interest in science but I thought it was interesting learning that an animal could actually live that long. When they mentioned the fact of the cold temperatures promoting longevity, it reminded me of how a female can freeze there eggs and have a baby later when they decide. It's like the opposite of hatching which occurs through warm temperatures.

  • jareds-cel
    8/31/2016 - 10:07 a.m.

    Famous scientists believe that the deeper and colder it is the longer a species will live. Also a slow metabolism helps the animal survive longer than most. The Greenland shark lived to be 311 years old while the animal behind that one only lived to be around 200 years of age.

  • monicas-ste
    9/01/2016 - 01:29 p.m.

    This is really fascinating. I never knew of any animal that could live this long. This is cool.

  • noahr-ste
    9/16/2016 - 01:55 p.m.

    Its crazy how the deeper and colder you are is the the better chances of survival for a animal and that is how whales live so long. It is like frozen food it last way longer because its frozen its weird how it can preserve health of a animal though.

  • zakrym-ste
    9/19/2016 - 01:04 p.m.

    Holy Guacamole! I think it is pretty cool that they have been around for so long. They are very old. lolz

  • jacklynt-ste
    9/22/2016 - 02:02 p.m.

    In the arctic an animal has been lurking around for centuries. The animal is nearly 392 years old. I think this is really cool because then this animal has been living since war times and most defiantly longer then any human.

  • kaileew-ste
    9/26/2016 - 02:08 p.m.

    A grey shark, estimated to be born around 400 years ago, has been named the oldest animal with a backbone. Before this, a bowhead whale was the oldest living for 211 years. Scientists still don't know why the whales live this long but observers hope they will figure that out soon.

  • isabelj-lam
    10/28/2016 - 01:36 p.m.

    I never knew any animals could live that long! Especially sharks! I thought mammals would be the longest living with back bone, buts it is Greenland shark!

  • gracer1-man
    11/03/2016 - 11:20 a.m.

    This article is very interesting. I didn't know or would even guess that the oldest animal (with a back bone) was a shark from Greenland. The scientists' assumptions make sense and I too would probably make the same. Apparently due to the cold water the shark is living in, along with the slow metabolism, helps them survive longer. At least that's what the scientists are thinking.

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