Another “Did You Know”!

Ah yes! We found this so very interesting and no, we did not know. We wonder how many of you knew!

When we think of animals with long life spans, tortoises usually come to mind first. But even Jonathan, a roughly 189-year-old giant tortoise who resides in St. Helena, would seem positively young compared to the average Greenland shark. Somniosus microcephalus(“sleepy small-head”) can live as long as 400 years or more, meaning there are probably some of them swimming the depths right now who predate the United States — or Sir Isaac Newton, for that matter. The deep-sea dwellers, most commonly found in the Arctic Ocean and North Atlantic, are the world’s longest-living vertebrates. 

In addition to their longevity, they’re also quite, well, long: Greenland sharks can reach a length of 23 feet and weigh over 2,000 pounds, though the average specimen isn’t quite that imposing.

Despite also being among the world’s slowest sharks — they’ve been observed “almost immobile” while “practically hovering” above the sea floor — they’re capable of quick bursts of speed that allow them to target fast-moving seals, Greenland halibut, Atlantic cod, and other marine creatures.

As for how and why Greenland sharks live so long, it’s partially explained by their preferred environs: Cold-blooded animals in cold environments tend to have slow metabolic rates, which are associated with longevity (although scientists are still teasing out why) and “deep and cold equals old“.

So, how about that?! Something to ponder over the weekend.