Secret to world’s longest-living vertebrate’s 500-year lifespan revealed

A recent study suggests that the extraordinary lifespan of the Greenland shark, the oldest known living vertebrate species, may be significantly influenced by muscle metabolic activity.

These insights could be crucial for the conservation efforts of this species, which faces threats from climate change, and might even offer new avenues for enhancing human cardiovascular health.

“Aging is a very complex system, and I think many factors could be involved in the Greenland sharks’ extreme lifespan,” Ewan Camplisson, the lead researcher, told Interesting Engineering (IE).

Greenland sharks ( Somniosus microcephalus ) hold the record for the longest-living vertebrates, with an anticipated lifespan of at least 270 years and the potential to live beyond 500 years.

Studying the longevity of Greenland sharks

It was previously believed that the remarkable longevity of Greenland sharks was primarily due to their frigid habitat and limited physical activity. However, the reasons behind their extraordinary lifespan seem to be significantly more intricate.

“Most species show variation in their metabolism when they age,” says Camplisson. To assess the sharks’ metabolism, the researchers performed enzyme assays on preserved muscle tissue samples from Greenland sharks and evaluated the metabolic activity of these enzymes across various ages and environmental temperatures.

Unexpectedly, the results revealed no significant differences in muscle metabolic activity across different ages, indicating that the sharks’ metabolism does not decline over time. This finding suggests that stable metabolic activity might be a crucial factor in their longevity.

“By showing that their [Greenland sharks’] metabolism doesn’t seem to alter with age in their red muscle, I think this shows the shark has a range of adaptations which together lead to its long lifespan,” Camplisson tells IE.

“The fact the Greenland sharks don’t show change in activity with age suggests they may not have the same gradual accumulation of damage to their metabolic enzymes and thus they don’t need to alter their metabolism in the way other animals such as humans would,” he added.

How does metabolic rate influence the sharks’ response to climate change?

The study’s results also indicate that the metabolic enzymes of Greenland sharks exhibit significantly higher activity at elevated temperatures. “This would suggest that the shark’s red muscle metabolism is not specially adapted for the polar environment,” says Camplisson.

In a rapidly changing climate, species with long lifespans and limited adaptability are at a heightened risk of extinction . Female Greenland sharks, which may not reach sexual maturity until 150 years old, have extended generation times that significantly reduce their ability to adapt to human-induced environmental changes.

When it comes to conservation, apart from the obvious calls for lowering ocean temperatures, Camplisson has certain suggestions for the Greenland shark. “A more specific plan for the Greenland shark would be to control the expansion of fishing into Arctic waters. With the loss of ice in the Arctic, new fishing regions are opening and these should be monitored very closely to determine rates of bycatch of Greenland sharks,” he says.

“This monitoring would also give insight into where the populations are being found in most significant numbers and to track if the warming waters are forcing the sharks into a shrinking region with cold water,” Camplisson adds.

How does this link to human health?

Studying cardiovascular and metabolic activity in sharks could lead to interesting avenues of research pertaining to human health. “A shark’s cardiovascular system varies significantly from humans. So making direct comparisons between the two whole systems is not easy,” Camplisson opines.

“We hope that this and future work will allow us to determine which adaptations to the metabolic enzymes and metabolism generally allow them to have such consistent activity with age. A big factor to investigate is mitochondrial dysfunction and if Greenland sharks show any signs of this at all,” he concludes.

This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5 ^th July 2024.