A Greenland shark received the title of oldest living animal with a backbone. The female shark apparently was born about 400 years ago in the Arctic Ocean. She died only recently. Scientists now put the entire Greenland shark species near the top of the longevity list.
An international team of biologists and physicists estimated the age of 28 dead female Greenland sharks. They studied tissue in the sharks’ eye lenses to make their estimates. According to the scientists, the carbon level in a shark’s lens is determined before birth. It does not change over the animal’s life. So measuring that carbon gives an idea of when the fish was born.
Eight of the sharks studied were probably 200 years or older. Two likely date back more than three centuries. Until this discovery, the record holder for oldest vertebrate animal was a bowhead whale that hit 211, says marine biologist Julius Nielsen.
The oldest of the Greenland sharks examined was nearly 16.5 feet long. Her age was estimated to be 392 years old when she was caught about four years ago. But even with the carbon testing, the calculation comes with a huge margin of error—plus or minus 120 years! That means she was probably born between 1500 and 1740. Nielsen is content to settle on the mid-point as the most likely birth year: 1620.
"It's an estimate. It's not a determination," Nielsen says. "It is the best we can do."
Even at the lowest end of the error margin, the shark would have been 272 years old when it died. That still makes it the longest-living known animal with a backbone, Nielsen says.
Greenland sharks love near-freezing temperatures. The cold water and the slow metabolism that comes with it might have something to do with their long lives, Nielsen thinks. Christopher Lowe of the shark lab at California State University, agrees. “Deep and cold = old when it comes to fishes,” he says.
Some animals without backbones live even longer.
The AnAge animal longevity database puts the Greenland shark at spot #4 on its list of longest-living animals. It follows the hexactinellid sponge (claiming 15,000 years!), the epibenthic sponge (1,500 years), and the ocean quahog clam (507 years). The oldest human recorded in modern times lived 122.5 years.
That obviously doesn’t include biblical history. Before the flood, Methuselah lived 969 years, making him the oldest person ever on record.
