- Greenland sharks can live up to 400 years, making them the longest-lived fish species.
- Scientists are studying these sharks to unravel the secrets of their long lifespan.
- Understanding the lifespan of Greenland sharks could improve research into human health and aging.
Abigail Adams, the wife of the second US president, was born in 1744. It is quite possible that there are still Greenland sharks alive today that swam in the North Atlantic Ocean at that time.
There is no doubt that these large, carnivorous sharks can live for hundreds of years. In 2016, researchers discovered that they can live for at least 272 years, but they can live up to 400 years.
Why these sharks live so long is a bigger mystery, though. Some theories revolve around the shark’s slow growth rate and low metabolic rate, but research is still ongoing.
Scientists hope that unlocking the secrets of how these fish age could help humans live longer, healthier lives. We probably won’t reach 400 years old, but even extending the average human lifespan by an extra decade would be a breakthrough.
One scientist on the hunt is Ewan Camplisson, who studies the sharks’ metabolism for clues about their aging process.
“A better understanding of the anatomy and adaptations of a long-lived species like the Greenland shark could help us improve human health,” Camplisson, a PhD student at the University of Manchester, told Business Insider.
A lifelong slow metabolism
Greenland sharks are found primarily in the Arctic Ocean and the northern Atlantic Ocean. They are peaceful swimmers that can grow to between 2.5 and 7 meters long and weigh up to 1.5 tons, according to National Geographic.
The predators feed on salmon, eels, seals and even polar bears, if given the chance. However, they can likely go long periods between meals. A 493-pound fish could survive on 2 to 6 ounces of food per day, according to a 2022 study.
New research by Camplisson, presented earlier this month at the Society for Experimental Biology annual conference, suggests that shark metabolism may not slow down as they age, which could explain why sharks live so long.
This is not true for most animals, including humans. For example, human metabolism tends to slow down in later life, which can contribute to unhealthy weight gain.
Camplisson looked at the activity of five metabolic enzymes in preserved Greenland shark muscle tissue. “In most species, you would expect that as an animal ages, the activity of these enzymes would vary,” he said.
“Some of these will decline over time, as they become less functional or deteriorate. Others will compensate and increase their activity to ensure the animal continues to produce sufficient energy,” he added.
In the Greenland sharks he looked at, which were estimated to be between 60 and 200 years old, he found no significant variation in enzyme activity. Of course, a Greenland shark can be 200 years old, so that may not be true if they are in their third or fourth century.
Camplisson plans to study more enzymes to see if and how they change as the sharks age.
Aging is complicated
Much work remains to be done before this type of research can be applied to humans.
“Aging is an incredibly complex system and we still don’t have a definitive answer as to exactly how it works,” Camplisson said.
Metabolic changes, for example, are just one part of human aging. Genetic errors, protein instability, and several other processes are among what are known as the “hallmarks of aging.” Camplisson believes sharks have more to teach us in this area.
“We want to look at some of these features more closely to determine whether the Greenland shark is showing signs of traditional aging,” he said.
Greenland sharks have survived for centuries thanks to their remarkable aging process, but it can also be a double-edged sword, as their habitat is rapidly changing.
Camplisson said the species, which is considered “near threatened” by the World Conservation Union, may be too slow to adapt to climate change, marine pollution and other stressors.