Greenland sharks don't exactly look like the fearsome beasts of thriller movies, but the slow-moving creatures certainly are remarkable in a different way. Scientists believed that they have incredible life-spans and that they found a female Greenland shark that was the oldest vertebrate — meaning it had a backbone — living on Earth.

The researchers published their work Thursday in Science. They concluded a gray shark they studied, which recently died, was born some 400 years ago in icy Arctic waters. That puts the Greenland shark at the top of an enviable list of oldest vertebrates. The scientists used a dating technique that found eight of 28 dead female Greenland sharks were at least 200 years old, according to the study. The calculation for the oldest shark does come with a rather wide margin of error, plus or minus 120 years.

"I am 95 percent certain that the oldest of these sharks is between 272 and 512 years old,” Julius Nielsen, lead author of the study and a marine biologist at the University of Copenhagen, told the Los Angeles Times. "That’s a big range, but even the age estimate of at least 272 years makes it the oldest vertebrate animal in the world."

The prior oldest vertebrate was reportedly a bowhead whale that reached 211 years old. The best guess is the shark was born between 1500 and 1740. The most likely birth year is 1620, the same year the Mayflower endeavored to cross the Atlantic, bound for the New World.

"It's an estimate. It's not a determination," Nielsen told the Associated Press about the shark's age. "It is the best we can do."

Certain animals without backbones can live longer that vertebrates, with one clam lasting 507 years and some sponges living for thousands of years, according to the AP. Greenland sharks might live a long time, but they're apparently nearly blind and spend most their lives scavenging very cold water using a powerful sense of smell.

“They are basically a giant swimming nose,” Aaron Fisk, a professor at the University of Windsor who has studied the Greenland shark for two decades, told the L.A. Times.