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, an inhabitant 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. It 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. 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. It was caught around four years ago. But that calculation comes with a huge margin of error, plus or minus 120 years. This is 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. Its most likely birth year was 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. That still would be the longest-living animal with a backbone, Nielsen said. Other experts agreed.
 
Joao Pedro Magalhaes is a University of Liverpool aging researcher. He said because the study is based on an indirect measurement, he wouldn't necessarily concentrate on exact numbers, especially when they exceed 400 years. That is 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. He 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. He is the director of the shark lab at California State University Long Beach. He wasn't part of the study. But he praised it as creative and compelling.
 
Greenland sharks love cold water. They prefer temperatures near freezing. They are found 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. It 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. 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/tween56/what-oldest-animal/

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CRITICAL THINKING QUESTION
Why do cold temperatures promote longevity?
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COMMENTS (149)
  • elliota-orv
    8/29/2016 - 11:48 a.m.

    I think it is cool that a vertebrae animal like a grey shark can survive up to 400 years just because they have adjust their bodies to live in temperatures near freezing.

  • joeg-orv
    8/29/2016 - 03:01 p.m.

    I just now learned what the oldest animal is.

  • ericp-eat
    8/29/2016 - 05:31 p.m.

    The cold water promotes longer life because the cold water slows down the metabalime so it makes the shark live longer and this greenland shark lived tobe about 400 years old in the cold waters of Greenland.

  • jadenw-ric
    8/30/2016 - 11:33 a.m.

    I agree that some animals with backbones do live longer because like greenland sharks with backbones the longest one was 16.5 feet long,and they estimated it to be 392 years old.I agree that Animals live longer than humans and any other vertebrae they say in the article.

  • chadm-orv
    8/30/2016 - 08:24 p.m.

    I think its incredible that a shark could live that long I never heard of this species of shark. I think it has something to do with how when you have a hot and cold cup of water and when you drop food coloring in the cold water it moves pretty slow, but if you put food coloring in the warm water it'll move a lot faster.

  • smatthew-dav
    8/30/2016 - 08:48 p.m.

    They probably cause a long lifespan because the body of the organism is immune to extreme temperatures. This could also help with the survival of the animals physical lifestyle.

  • piersonw-cel
    8/31/2016 - 10:59 a.m.

    A female Greenland shark is calculated to be the world's oldest animal with a backbone. It is estimated to be nearly 400 years old. Before now, the record holder was a bowhead whale, which was 211 years old.

  • colem2-whi
    9/02/2016 - 10:53 a.m.

    I honestly dont get this

  • jacoba-kul
    9/06/2016 - 12:25 p.m.

    I think there are some older animals. We have only found the oldest animal that has died. Hidden somewhere in the ocean there could be an animal that is still alive that is older. If there is an older creature out there it is probably alive because it has been hiding.

    • sages-kul
      9/08/2016 - 12:34 p.m.

      i think that there is other life that can live longer. i think trees and certain fungi that has an enormous lifespan. i think there some trees in the redwoods that are around 4 to 5 hundred years old.

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