Over 50 years ago, a Danish fishery biologist named Paul Marinus Hansen discovered that Greenland Sharks have a very slow growth rate. At a rate of only a few centimeters every several years, he determined that it would take a long lifespan to see a substantial growth in these sharks. Given the fact that Greenland Sharks can grow up to 16 ½ feet (5m) in length, it was speculated that some could have been around for a long time.
The Oldest Kid On The Block
Look up the word longevity in the dictionary and you might see a picture of a Greenland Shark. Not really, but we’d suggest that to Oxford if we could. Thanks to a carbon-dating process used on 28 Greenland Sharks this past summer, they are now officially the longest living vertebrae on the planet! How long have they been around? Let’s just say that one of the females topped out at about 400 years old! That’s easily 8 or 9 generations in most families. Prior to this discovery, the longest known living vertebrae was a Bowhead Whale who was aged at 211 years old. But when it comes to invertebrates, one solitary clam (named Ming) holds the record of all time at 507 years old!
Can you imagine that many candles on a birthday cake?
That’s A Long Time To Swim The Sea
The female that they determined to be the oldest shark currently on the planet is thought to be as young as 272, or as old as 512. But, scientists believe that she was born in the 17th Century, giving a roughly 400-year-old shark a birthdate around 1616. To put things in perspective as to how long this wondrous creature has been swimming the high seas, here are some of the things that went on around the planet over this shark’s probable lifetime.
- William Shakespeare dies
- Pocahontas arrives in England
- The first non-aristocratic, free public school in Europe opens in Italy
- One of the oldest towns in Mississippi, Natchez, is founded
- English Pirate Edward Teach is given command of a ship in the Bahamas
- Sir Winston Churchill’s son, John Churchill, suffers a paralytic stroke
- The United Provinces of South America declares freedom from Spain
- James Monroe wins the U.S. presidential election
- Rossini’s opera The Barber of Seville premiers in Rome
- President Woodrow Wilson incorporates the Boy Scouts of America
- German automobile company, BMW, is founded in Munich
- J.R.R Tolkien marries Edith Bratt in England, inspiring 2 literary characters
- The Democratic Party nominates the first female candidate for U.S. presidency; Hillary Rodham Clinton.
- The United Kingdom votes in a referendum to leave the European Union
- The World Health Organization announces an outbreak of the Zika virus
Not to mention all of the things that happened in between!
Greenland Shark Facts: Counting The Rings
Due the discovery of a slow growth rate compared to how large Greenland Sharks can grow, scientists always knew that they were old souls. Just how old was yet to be determined. A marine biologist named John Steffensen thought that by capturing a piece of the backbone of a shark, he could determine its age based on the growth rings, much like the way we count rings on a tree. There are some fish who are dated this way through the rings in their ear bones and Ming the clam was aged by counting the rings on his shell. Great White Sharks can be dated by the calcified tissue that grows in layers on their backbones. However, Greenland Sharks are very soft and have no hard parts where layers could be deposited. So when the backbone yielded no results, Steffensen consulted Jan Heinemeier who was a radiocarbon dating expert from Denmark. Heinemeier suggested that Steffensen measure the amount of carbon found in the lenses of the shark’s eyes.
Greenland Shark Facts: The Discovery
Steffensen and his assistant, Julius Nielsen, spent many years collecting Greenland Sharks that had died, mostly due to becoming trapped in nets used to catch other fish. Now, here’s where it gets all science-detailed. Once the duo had enough sharks to work with, they began by looking for the isotope carbon-14, which was left behind during the bomb tests in the 1950’s. The extra carbon made its way through the ocean ecosystems by the 1960’s, meaning that eye lenses formed during this time have more carbon-14. Thus, they determined the age of a few small sharks that were born in the 1960’s. By roughly knowing when a shark was born and what their growth rate was, they were able to determine the ages of Greenland Sharks based on that knowledge.
In A Class Of Their Own
What sets the Greenland Shark apart from the other oldest living creatures is that there are so many of them. Ming the clam is one-of-a-kind. Though there have been 2 other multi-centenarian species of clam that have turned up in the North Atlantic in recent years, most scientists believe that those are rare finds. But in the North Atlantic, you’ll find many Greenland Sharks slowly swimming through the deep waters.
The strangest thing about this shark is that females do not reach sexual maturity until they are at least 150 years old. Can you imagine? Repopulation of this species takes almost 2 human lifetimes! This is one reason why conservation of these sea creatures is so important. Of course, all sharks need to be considered special and looked after by humans. There is nothing to be gained by their extinction and much to be gained by their existence. The more we learn, the more we grow and that just makes sense for everyone.