The Stunning Number Of Years Greenland Sharks Can Live

Greenland sharks certainly have time on their side. For decades, scientists thought this species had a long lifespan, but they didn't have a great way to prove it. The shark's physical makeup presented a substantial hurdle for researchers. Unlike other sharks, Greenland sharks don't have growth bands on their spines, which can be used to determine age (via the National Oceanic and Atmospheric Administration). In 2016, however, new research provided a way to generate an age range for these massive undersea wonders and revealed that they can live for centuries, according to Science magazine.

Danish researchers discovered that proteins found in the lenses of the eyes of Greenland sharks could be carbon-dated to determine the approximate age of the animals. Carbon dating can only produce a broad range for the Greenland sharks' age, but still, the researchers made some impressive findings. The largest shark studied was a female that was estimated to be between 272 to 512 years old (via BBC), making the Greenland shark the longest-living vertebrate on the earth. The researchers think that this shark was probably around 400 years old. 

Greenland sharks threatened by fishermen

Julius Nielsen, the lead author of the 2016 study of the Greenland sharks explained to the BBC that "We had our expectations that we were dealing with an unusual animal, but . . . [we were] very surprised to learn the sharks were as old as they were." For the study, the researchers collected data from the lenses from 28 Greenland sharks. These specimens were largely found by fishermen after the sharks got accidentally caught up in their nets. In fact, one of the greatest threats to the Greenland shark's long-term survival is being caught up in nets and lines intended for other animals, according to the National Oceanic and Atmospheric Administration. The species used to be hunted for its liver, which was used as a machine oil (via BBC).

There's much speculation as to why these sharks can live so long. They definitely live life in the slow lane and are well-known for their sluggish swimming speed. They grow at a rate of only 1 centimeter a year, and they are not believed to reach sexual maturity until they are at least 100 years old. The cold waters of the North Atlantic Ocean may also play a role in the Greenland shark's longevity. According to Science magazine, the cold both slows the animal's metabolism and growth and encourages certain genes to fight the aging process.