Sharks often called "the denizens of the deep," are one of the longest-lived species on our planet. As reported by the Inquisitr last week, Portuguese scientists were amazed when they captured a "shark from the age of the dinosaurs" off the Algarve coast. The rare frilled shark was caught by a trawler from the country's Institute for the Sea and Atmosphere, and scientists claim that the unusual species has survived virtually unchanged for 80 million years.
If you are a fan of the BBC television series The Blue Planet you will have been spellbound by the amazing pictures of life in our deepest oceans. The series has revealed that there is previously undiscovered life in even the deepest and darkest parts of the ocean. These discoveries reaffirm just how much we still have to learn about oceanic life. In fact, it is often claimed that we know more about the surface of the moon than we do about our deepest oceans.
Of course, sharks are not the only sea creature that dates back for millions of years. Scientists claim that horseshoe crabs date back even further than the frilled shark. According to Newsweek, scientists estimate that the horseshoe crab has been around for 450 million years, long before sharks, or the first cartilaginous fish had even been born. The Coelacanth, a huge night sky colored fish, dates back over 400 million years and is still swimming in our deep oceans today. To put that into perspective, these animals predate the dinosaurs by 170 million years.
Sharks hold a special fascination for scientists, partly because of their fearsome reputation, but also because they are so long-lived. As reported by National Geographic, a scientific study claims that the Greenland shark is the longest-lived vertebrate on earth. The Greenland shark inhabits the deep and cold waters of the North Atlantic, and a study suggests that they could have a lifespan of up to 500 years.
Scientists claim that the Greenland shark doesn't even begin breeding until it reaches 150 years of age. A more recent article by National Geographic points out that working out a sharks age is not an exact science. Scientists have traditionally relied on counting calcified growth bands that form on a shark's cartilaginous vertebrae. Recent studies have suggested that carbon dating radioactive isotopes in the shark's growth bands.
Studies of sharks that were alive when nuclear bombs were tested in the 1950's and 1960's show that radioisotopes were present showing the shark to be at least 65-years old. This was more than twice as old as their growth bands suggested. These new studies suggest that shark species like the Great White shark may live to be 300 years old.
These studies show that we still have so much to learn about sharks, animals that have populated the earth's oceans since prehistoric times.