By Courtney Cooper
How Old do Sharks get?
The earliest shark fossil discovered dated to over 450 million years ago. The earliest human fossil to be found was over 3.2 million years ago. Sharks existed long before humans and dinosaurs, in fact they have survived 5 global mass extinctions. We have the privilege of still seeing these endangered creatures today in our oceans. So how old do sharks get?
For us to understand how old sharks get, we have to understand how scientists are able to estimate their age. Like trees, we can tell the age of sharks by counting growth bands on the sharks’ vertebrae (fin spine). In the below image of a blue shark vertebra, we can see the first ring or band identified with a black dot. This is the sharks’ Birth band. Each band that is on the outer edge represents roughly 1 to 1 and half years after the shark’s birth. In this article, we will take a closer look at what the average lifespan of different types of sharks are. We also discuss further shark facts that you might be interested in! Apex Predators provides the best kelp forest diving cape town.
What is the Average Lifespan of Sharks?
We can also use radiocarbon dating to estimate the age of fossils. Radiocarbon dating is used to determine the age of organic materials as far back as 60,000 years. This scientific method is built on the fact that all living organisms absorb carbon-14 into their tissue. Once the organism dies, the carbon-14 begins to change form into other atoms as time passes. Scientists are then able to use the remaining carbon-14 atoms to determine how long the organisms has been dead.
Let’s start with the shark with the longest lifespan, the Greenland Shark. Scientists estimate these pre-historic sharks to live to at least 250 years old and as long as 400 years. Unlike most sharks, the Greenland Shark’s vertebrae are too soft to form growth bands. Scientists can only estimate their age by their size. These sharks tend to grow less than 1 cm per year and can grow to over 6 meters. Flying under the radar can be best used to describe this shark. They inhabit the artic and subarctic waters where temperatures range from -2 degrees and 7 degrees Celsius. The key to their longevity can be attributed by their slow swim speed averaging 2.6km/h. One of their biggest advantages is that their shark meat is toxic due to TMAO (trimethylamine oxide) within their tissue. TMAO is vital to their survival in the ice-cold waters by stabilising their enzymes and proteins. Impressively, these sharks are the longest-living vertebrate on earth!
The Great White Shark’s average lifespan is between 40 and 70 years old. The oldest Great White to be recorded is 73 years old. Unfortunately, fisherman have been killing the Great White Shark for many years for their fins and teeth. Unlike the Greenland Shark, the Great White tissue is not toxic, and humans commonly eat their fins in soup as a delicacy. In addition to their body parts, they are also killed as a trophy for sport. Not all fishermen intentionally hunt the Great White, due to commercial fishing, these sharks can die from being tangled in netting.
There is a striking difference between the life span of the Greenland Shark and that of the Great White Shark, a whole 330 years! The Greenland Shark is hard to spot, and lives hidden in deep and freezing waters. The Great White Shark is an apex predator and surface feeder, they migrate from South Africa to Australia and from the California coast far out into the middle of the Pacific Ocean. We can now see how these sharks’ way of life and biological makeup determine their lifespan.
If you enjoyed this article, you may also be interested in our other article, where we discuss truths about sharks that might surprise you. December is approaching. Book your Cape Town shark cage diving trip.
