Greenland sharks can live more than 500 years, making them the longest-living vertebrates on Earth, but their extreme longevity may now threaten their survival.
Why unhurried growth and long life put Greenland sharks at risk
These sharks grow extremely slowly, adding only about one centimeter per year, and do not reach sexual maturity until they are around 150 years old. In other words populations recover very slowly from any losses, whether from natural causes or human activity such as bycatch in fisheries. Their low reproductive rate makes them especially vulnerable to even small increases in mortality.
How scientists determined the sharks‘ extraordinary lifespan
Researchers used radiocarbon dating of eye lens nuclei to estimate age, a method that relies on carbon-14 levels from mid-20th century nuclear testing. One shark studied was estimated to have been born around 1626, placing its birth during the Thirty Years‘ War in Europe. Matthias Schaber from the Thünen Institute of Sea Fisheries noted that Greenland sharks commonly live 400 years, with some individuals possibly exceeding 500 years.
What the sharks eat and how they hunt despite slow speed
Greenland sharks swim at an average speed of just 1.2 kilometers per hour, making them among the slowest sharks known. Despite this, they have been found with seals, polar bears, and even possible human remains in their stomachs. Scientists believe they likely ambush sleeping seals rather than chase them, as studies show no evidence of burst-speed capability.
How Greenland sharks navigate in dark Arctic waters
Living in near-total darkness, these sharks rely heavily on their sense of smell and specialized electroreceptors to detect weak electric fields from prey. Whereas their eyes are often clouded by parasites and were once thought nonfunctional, recent research published in Nature Communications found that neither the retina nor cornea shows significant degeneration, even in very old individuals.
What this means for future conservation efforts
The combination of extreme age, slow reproduction, and vulnerability to accidental capture means Greenland shark populations could decline without obvious signs until it is too late to act. Conservation strategies may need to focus on reducing bycatch in Arctic and North Atlantic fisheries and monitoring long-term population trends, given the species‘ inability to rebound quickly from losses.
How old can Greenland sharks actually receive?
According to age estimates using radiocarbon dating, Greenland sharks can live 400 years or more, with some individuals possibly exceeding 500 years.
Why don’t Greenland sharks swim faster if they need to catch prey?
Studies show no evidence of burst-speed capability; instead, they likely rely on ambushing seals that are sleeping in the water to avoid polar bears.
