Biologists were surprised to find a mysterious cold-water shark thousands of miles away from its natural habitat, according to a recent marine study. It is a Greenland shark, the oldest vertebrate on Earth, which was discovered in the tropical Caribbean Sea.
Researchers were temporarily tagging and capturing tiger sharks off the coast of Belize when they encountered the mysterious shark, said a paper recently published in the scientific journal Marine Biology.
Initially, scientists suspected it could be a sixgill shark, a dominant deep-sea predator, but by photographing the rarely seen animal, they confirmed its identity as "most likely" a Greenland shark, Science Alert reports.
"Suddenly we saw a sluggish, sluggish creature under the surface of the water," Devanshi Kasana, a biologist and PhD candidate in Florida International University's Predator Ecology and Conservation lab, reported Mashable. "It looked like something that would exist in prehistoric times."
Greenland sharks are the longest-lived vertebrates on Earth, with a staggering lifespan of 250 to 500 years, according to the National Ocean Service.
Sharks live thousands of feet underwater in total darkness and are rarely seen or photographed, and few details are known about their incredibly long lives, Science Alert says.
In the depths of the water, they grow, move and age slowly. Their slow, energy-conserving lifestyle is an essential adaptation to the nutrient-poor deep sea.
Finding a Greenland shark near a coral reef off Belize was unexpected but plausible. These dark sharks thrive in the deep seas of the Arctic and may inhabit other deep ocean regions, including the Caribbean.
Greenland sharks are primarily scavengers, eating everything (dead or alive), including fish, seals, polar bears and whales, Science Alert says.
The Greenland shark seen now was already on the cover of magazines in 2016 due to its incredible old age. This animal would have been born in 1505, a year before the death of Christopher Columbus.
It is a slow-growing shark as it increases in size approximately 1 centimeter per year and this specimen measures 550 centimeters so they knew they had found the Holy Grail of animals.
To estimate the age, they used a mathematical model that analyzed the shark's lens and cornea. The researchers removed the eyes of 28 female specimens that had been accidentally caught.
Of the 28 Greenland sharks analyzed, ages ranged from 272 to 512 years, giving an average life expectancy of 392 years, and they discovered that this living shark could be up to 518 years old.
Carbon tests have a margin of error of 120 years, which means that in the worst case it would be 395 years old.
But the new study, in addition to age, determined other fascinating data: the shark does not reach sexual maturity until it is 150 years old, so it must be protected from fishing to prevent it from becoming endangered.
Furthermore, it can be fundamental for human beings. Understanding how they live so many years without developing cancer or other diseases may provide the answers to delaying human aging.
The Greenland shark is a cold-blooded animal, it has few offspring and lives in the Arctic Ocean, where temperatures are so low that cell activity is very slow.
In those same waters lived Ming, a clam from Iceland who was 507 years old when he died.
