Greenland Sharks May Hold Secrets to Longer Human Lives

Abigail Adams, the wife of the second US president, was born in 1744. Greenland sharks alive today may well have been swimming in the North Atlantic when she was born.

These huge predatory sharks are unquestionably capable of living for centuries. Researchers established in 2016 that they can live for at least 272 years, although they may reach 400 years of age.

What gives these sharks such exceptional longevity remains less certain. Their very slow growth and low metabolic rate are among the proposed explanations, but scientists are still investigating.

Researchers hope that revealing how these fish grow old may offer ways to help people live longer and healthier lives. Humans are unlikely to live to 400, but adding even a decade to average human lifespan would be a major advance.

Ewan Camplisson is one of the scientists pursuing those answers. He has been examining the sharks' metabolism for evidence of how they age.

"Better understanding the anatomy and adaptations of a long-lived species such as the Greenland shark may allow us to improve human health," Camplisson, a PhD student at the University of Manchester, told Business Insider.

Greenland sharks and their slow metabolism

Greenland sharks, found mainly in Arctic and North Atlantic waters, are unhurried swimmers. According to National Geographic, they can grow to between 2.4 and 7 metres in length and weigh up to 1.4 tonnes.

They prey on salmon, eels, seals and, when the opportunity arises, even polar bears. They also appear able to endure extended periods without feeding: a 224 kg fish could manage on roughly 57 to 170 g of food each day, according to a 2022 study.

Camplisson presented new research at the Society for Experimental Biology Annual Conference earlier this month. It indicated that the sharks' metabolic rate may not decline as they get older, potentially helping to account for their extraordinary lifespan.

That pattern differs from that of most animals, including people. Human metabolism, for instance, commonly becomes slower in later life, which may contribute to unhealthy weight gain.

For his work, Camplisson examined the activity of five metabolic enzymes in preserved Greenland shark muscle tissue.

"In most species, you would expect as an animal ages for these enzymes' activity to vary," he said.

"Some of them will show reduction over time as they may begin to fail or degrade, while others will then compensate and increase in activity to make sure the animal still produces enough energy," he added.

Among the Greenland sharks he studied, estimated to be between 60 and 200 years old, enzyme activity showed no meaningful variation. A 200-year-old Greenland shark could, however, be only middle-aged, so this finding may not apply once they enter their third or fourth century.

Camplisson intends to investigate additional enzymes to find out whether, and in what way, they alter as the sharks grow older.

Why ageing remains complex

Considerably more research is needed before findings of this kind can be applied to humans.

"Aging is an incredibly complex system, and we still don't have a definitive answer to how exactly it works," Camplisson said.

Metabolic changes are only one element of human ageing, for example. Genetic mistakes, unstable proteins and several other mechanisms form part of what are called the "hallmarks of aging". Camplisson believes Greenland sharks may have further lessons to offer in these fields.

"We want to look closely at some of these hallmarks to determine if the Greenland shark shows any signs of traditional aging," he said.

Greenland sharks face a changing environment

The unusual ageing process that has enabled Greenland sharks to endure for centuries may also leave them vulnerable as their habitat changes quickly.

Camplisson said the species, classified as "Near Threatened" by the World Conservation Union, may adapt too slowly to climate change, marine pollution and other pressures.

Read the original article on Business Insider.

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