Natural Curiosities: Long Life in the Slow Lane

In the 1930s, a marine biologist caught a Greenland shark that changed how we think about aging. Well, he actually caught hundreds of the sharks, but he was fortunate enough to catch the same shark twice in successive seasons (the shark in question did not enjoy the same good fortune). The biologist measured the creature and was surprised to discover it had grown just a centimeter over the past year. Adult Greenland sharks can be twenty-four feet long, and such a slow growth rate suggested they must have extraordinarily long lives.

For nearly a century, that was about the limit of our understanding of the longevity of these strange, mostly unstudied creatures.

Sluggish-looking fish, Greenland sharks are usually colored a mottled gray-brown, with stubby fins and a rounded snout. Their eyes often appear to have tentacles, because an inches-long, worm-like parasite loves to colonize them. Most of their lives are spent cruising through the very deep North Atlantic; they’re regularly tracked as many as six