Greenland shark revealed to have longest life expectancy of all vertebrates

British scientists made an incredible discovery about the Greenland shark, specifically that it is the longest living vertebrate with an incredibly long lifespan. A team of researchers led by Julius Nielsen of the University of Copenhagen has determined that it can live to at least 272 (possibly up to 500) years old.

This shark grows slowly: the cold environment retards its metabolism, safeguarding tissue from damage. And its actual body size increases by only a centimeter per year. Female Greenland sharks are in no rush to reproduce; they likely reach mid-life at 156 years old, when they’re finally ready to start breeding.
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'Given that the Greenland shark is one of the largest carnivores in the world and the king of the food chain in the Arctic ocean, it is almost unbelievable that we don't know if this shark lives to 20 or to 1000 years. Both lifespans have been suggested,' says marine biologist Steven Campana at the University of Iceland, Reykjavík, who didn't participate in the study.
Sharks are made of mostly cartilage, which makes it difficult for scientists to pinpoint their exact age. So the team focused in on the Greenland shark’s eyes instead.

Vertebrate eye lens nuclei contain proteins that form prenatally and some remain unchanged throughout life as they are metabolically inert. This means that a radioactive carbon-14 signature is locked into the lenses from birth. By comparing carbon-14 measurements with historical isotope data, the team obtained a timestamp of when the proteins formed to allow them to put an age to the sharks.

The findings could affect the Greenland shark's conservation status since slow growth and limited reproduction make them particularly vulnerable to overfishing.

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Posted by Slaustz, Published at August 14, 2016 and have 1 comments