By Virginia Rose Whalen
When you look deep into the ocean, the world you will see is colder, darker, and slower.
The species who live there have to adapt to these harsh environments by moving in slow motion. Their metabolism slows down, and their growth – even slower. They live a life so different from our own, it’s almost unimaginable.
Living the slow life can also mean surviving for a really long time. Take the Greenland Shark (Somniosus microcephalus) for example. This species resides deep in arctic waters, typically reaching more than 13 feet in length. A 2016 study discovered that these sharks can live to be a whopping 400 years old, and don’t reach reproductive maturity until at least 150. The authors of the study used radiocarbon dating on the eye lenses of deceased specimens in order to determine their age. It was also estimated that the sharks grow less than a centimeter a year, which contributes to their longevity.
Despite being so slow and so old, Greenland Sharks are considered to be the top predators of their food chain. Though they were long assumed to only scavenge for things that have already died, a 2013 study found that they are actually capable of catching live prey. They eat things like Atlantic cod, wolffish, and even harbor seals.
We still have a lot to learn about how deep sea fish like the Greenland Shark live. With most of the ocean left unexplored, there are almost certainly more fascinating species out there.
Nielsen, J., Hedeholm, R. B., Heinemeier, J., Bushnell, P. G., Christiansen, J. S., Olsen, J., Ramsey, C. B., Brill, R. W., Simon, M., Steffensen, K. F., & Steffensen, J. F. (2016). Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus). Science 353(6300), 702-704.
Nielsen, J., Hedeholm, R. B., Simon, M., & Steffensen, J. F. (2013). Distribution and feeding ecology of the Greenland shark (Somniosus microcephalus) in Greenland waters. Polar Biology 2014(37), 37-46.