Some species on Earth demonstrate an extraordinary ability to endure for centuries, even millennia, defying conventional understanding of life’s limits. This remarkable persistence highlights the diverse strategies evolution has forged for survival.
The Record Holder
The animal currently recognized as the longest-living vertebrate on Earth is the Greenland shark (Somniosus microcephalus). This large shark inhabits the frigid depths of the North Atlantic and Arctic Oceans, typically found in cold waters between 100 to 1,200 meters deep.
Estimates suggest the Greenland shark can live for at least 272 years, with the oldest individual studied believed to be around 392 years old, potentially reaching 512 years. This astounding age is determined through radiocarbon dating of the shark’s eye lens nuclei. The proteins within these lenses form before birth and remain metabolically inactive, preserving a chronological record of its age.
Secrets to Enduring Life
The extraordinary longevity observed in the Greenland shark and other long-lived organisms is often attributed to a combination of biological and environmental factors. A primary mechanism contributing to the Greenland shark’s extended lifespan is its remarkably slow metabolism. Living in consistently cold, deep-water environments drastically reduces the metabolic rate of these sharks, slowing down their biological processes and energy expenditure. This physiological adaptation allows them to grow at an exceptionally slow pace, less than one centimeter per year, and delays sexual maturity until they are around 150 years old.
Research indicates that the Greenland shark’s metabolism remains stable throughout its life, suggesting a lack of the typical age-related degeneration seen in most other animals. Beyond individual species, a general principle observed in many long-lived creatures is that a slower metabolic rate can correlate with a longer lifespan. This “rate of living” theory posits that organisms burning fewer calories daily tend to age more slowly.
Efficient cellular repair mechanisms also play a significant role in maintaining cellular integrity over long periods. Organisms with extended lifespans often possess robust systems that repair DNA damage and remove waste materials, preventing cellular breakdown and supporting overall cellular balance. Some long-lived species exhibit genetic adaptations that provide enhanced protection against cellular damage. Stable habitats, such as the deep sea, also contribute by offering consistent temperatures and reduced exposure to predators, minimizing biological stress.
Beyond the Record: Other Ancient Organisms
While the Greenland shark holds the title for the longest-living vertebrate, extreme longevity extends across various kingdoms of life. Among non-colonial animals, the ocean quahog (Arctica islandica), a type of clam, is notable for its exceptional lifespan. One individual was determined to be 507 years old. Its age is precisely measured by counting growth rings on its shell, much like tree rings. This mollusk thrives in cool northern waters, exhibiting slow growth and minimal metabolic costs.
In the broader animal kingdom, some colonial organisms demonstrate even more astounding lifespans. Glass sponges are estimated to live for over 10,000 years, making them among the oldest animals on Earth. Similarly, certain black corals have been radiocarbon-dated to be over 4,000 years old.
The plant kingdom also showcases remarkable longevity. Pando, a colossal clonal colony of quaking aspen trees, is considered one of the oldest living organisms, with estimates ranging from 9,000 to over 80,000 years. This single organism consists of genetically identical trees connected by an extensive underground root system, continually regenerating itself as individual stems die. Another ancient plant is the Great Basin bristlecone pine, with individual trees recorded at nearly 5,000 years old. These diverse examples underscore that extreme longevity is a widespread phenomenon, achieved through a myriad of biological adaptations across the planet.