A new record has been set for the oldest vertebrate, and it’s not a giant tortoise or Bowhead whale. Instead, the record-holder appears to be the Greenland shark, which new evidence suggests lives can live for 400 years, with average adults exceeding two centuries.
Greenland sharks live in the North Atlantic at both the surface and to depths of around 2 kilometers (at least 1.3 miles). They are poorly studied, although their status as among the slowest of sharks has been known for a while. A slow-moving lifestyle usually goes with a long lifespan, but no one knew just how long this meant for Somniosus microcephalus until Julius Nielsen of the University of Copenhagen collected the eye lenses of 28 female sharks caught as bycatch during scientific surveys of Greenland.
The ages of fish are usually calculated from calcified tissues, but Greenland sharks don’t have any that could be tested. The center of the eye is formed during embryonic development, and being made of inert crystalline proteins, does not experience a change of atoms through an individual’s lifespan. Consequently, radiocarbon dating of these proteins has been used to estimate the age of animals where this is hard to measure through other means.
Females were chosen because they outgrow males, reaching typical sizes of 4 to 5 meters (13 to 17 feet).
A Greenland shark caught as by-catch by the research vessel Palmut. Julius Nielsen