Scientists have found what they believe to be the world’s oldest living vertebrate, an 18-foot Greenland shark that might be more than five centuries old.
Although the shark was discovered in the North Atlantic Ocean several months ago, it was only this week when the researchers published their findings in the journal Science, and revealed the animal’s likely age range. According to marine biologist Julius Nielsen, the Greenland shark is believed to be no younger than 272-years-old, and possibly a ripe old 512 years of age. That would suggest that the recently-discovered Greenland shark might have been born before famous figures such as William Shakespeare, the International Business Times noted.
According to BGR, Greenland sharks are well-known for their longevity, as they could live for multiple centuries, and be well over 100-years-old by the time they reach sexual maturity. With the help of radiocarbon dating, the researchers were able to analyze a total of 28 Greenland sharks, and while the so-called oldest living vertebrate was estimated via this technique to be about 392-years-old, Nielsen and his colleagues considered possible margins of error to come up with the shark’s youngest and oldest possible age.
The International Business Times cited a previous study led by Arctic University of Norway professor Kim Praebel, which suggested that Greenland sharks could live to be 400-years-old. This paper was just one of several attempts to determine how long the animals could live, though these attempts have generally been unsuccessful. Nielsen’s research, however, also made use of mathematical modeling, focusing on the sharks’ lens and cornea to associate their size with their possible age.
“Fish biologists have tried to determine the age and longevity of Greenland sharks for decades, but without success,” University of Iceland shark expert Steven Campana said last year.
“Given that this shark is the apex predator (king of the food chain) in Arctic waters, it is almost unbelievable that we didn’t know whether the shark lives for 20 years, or for 1,000 years.”
Greenland sharks typically make their home in the deep, frigid waters of the Atlantic Ocean, from Canada to Norway. While not a primary source of food, these sharks are known to scavenge the carcasses of rotting polar bears, which lines up with a photo Nielsen shared in September, where the remains of a polar bear were shown taken from a Greenland shark’s stomach. According to the Florida Museum’s fact sheet on the sharks, the creatures could grow to an average length of eight to 14 feet, but could reach a maximum length of 24 feet.
Although the shark believed to be the oldest living vertebrate is quite a large example of its species at 18 feet long, it had most likely taken centuries to get to that size, as Greenland sharks grow only four-tenths of an inch (one centimeter) per year. This slow growth process is instrumental in helping scientists get a good idea of how old the animals are.
The shark in Nielsen’s study became a likely candidate for oldest-living vertebrate due to a number of factors, including its extremely slow metabolism and its environment. As noted by BGR, scientists believe that the frigid habitat of Greenland sharks helps them increase their average lifespan in different ways, as previous studies have linked cold environments to a slower aging process.