Marine biologists have confirmed that the Greenland shark (Somniosus microcephalus) is the longest-lived vertebrate species known to science, with individuals capable of surviving for over 400 years. According to a landmark study published in the journal Science, researchers determined the age of these deep-dwelling Arctic fish using radiocarbon dating of eye lens proteins, revealing a maximum lifespan that easily surpasses that of any other backboned animal on Earth.
Led by marine biologist Julius Nielsen from the University of Copenhagen, the 2016 research team examined 28 female Greenland sharks caught as accidental bycatch in fisheries research surveys. Because traditional methods of aging fish—such as counting growth rings in ear bones or fin spines—do not work for sharks lacking hard, calcified structures, Nielsen and his colleagues turned to the metabolic inertia of the eye lenses. Eye lens nuclei in Greenland sharks accumulate proteins formed when the animal is very young, providing a biological time capsule that records carbon-14 signatures from the ocean environment.
The implications of this extraordinary longevity extend far beyond marine biology. By understanding how these creatures endure centuries in the frigid, crushing pressures of the North Atlantic and Arctic oceans, scientists hope to unlock fundamental mechanisms regarding cellular aging, metabolic rate, and longevity across biological species. Yet, this slow pace of life also leaves the species uniquely vulnerable to modern ecological pressures.
The Science of Age: Radiocarbon Dating the Deep Sea
Measuring the lifespan of the Greenland shark required an innovative approach to marine chronology. According to research published by Nielsen and his team in Science, the eye lenses of these sharks consist of specialized tissue that grows continuously throughout the animal’s life without metabolic turnover. By analyzing the amino acids in the center of the lenses using radiocarbon dating, scientists could correlate the carbon-14 levels with the “bomb pulse” generated by atmospheric thermonuclear testing during the mid-20th century.
The results astonished the scientific community. The largest shark in the study—measuring approximately 5.02 meters (16.5 feet) in length—was estimated to be about 392 years old, give or take 120 years. This statistical window means the animal could easily have lived for more than four centuries, potentially having been born as early as the early 1500s during the Tudor period in Europe.
Furthermore, the study established that Greenland sharks grow at an extremely sluggish rate of less than one centimeter per year. This glacial growth rate correlates directly with their sexual maturity, which is not reached until the females are roughly 150 years old. Such a delayed maturity cycle means that historical fishing practices, accidental bycatch, and industrial ocean shifts impact populations on a generational scale that outlasts human institutional memory.
Ecological Role and Conservation Status
As apex predators in the dark, cold depths of the Arctic and North Atlantic, Greenland sharks play a crucial role in marine ecosystems. Despite their slow movement—earning them the moniker of the “sleeper shark”—they are opportunistic carnivores, with stomach contents revealing remains of seals, fish, and even scavenging on marine mammals. Their tissues contain high concentrations of trimethylamine oxide (TMAO) and urea, which act as natural antifreeze and protect their cells against deep-sea pressure, though this makes their fresh meat toxic to humans unless properly treated.
Conservation assessments underline the precarious nature of their long-term survival. The International Union for Conservation of Nature (IUCN) classifies the Greenland shark as Near Threatened, largely due to historical commercial fisheries that harvested them for liver oil, as well as ongoing mortality as incidental bycatch in modern trawling operations. Because populations take well over a century to replace reproducing adults, even low mortality rates can devastate local numbers.
Researchers and marine conservation bodies continue to monitor population dynamics across the North Atlantic, utilizing genetic tracking and satellite tagging to map migration patterns that span thousands of kilometers. As climate change alters Arctic water temperatures and marine ecosystems experience shifting trophic balances, understanding the baseline biology of the planet’s oldest vertebrates remains a vital priority for international marine science.
Worth a look