In the summer of 1998, executives over at the Discovery Channel introduced the world to Shark Week, a week-long block of television programming dedicated to the mysteries and science surrounding sharks. Since its inception 30 years ago, Shark Week has become a staple of summertime television in America, attracting an average of 20-million viewers each season while earning the title of the longest-running cable TV programming event in history.
At its inception, Shark Week’s programming was designed to increase conservation efforts and defuse some of the social stigmas around sharks. Lately though, the cultural phenomenon that Stephen Colbert joking deemed “one of the two holiest of American holidays,” has been generating criticism from the scientific community and shark advocates who believe that contemporary shows like Caged in Fear, Bloodline: The Spawn of Jaws, and Megalodon: The New Evidence, move further away from conservation and instead promote the dangerous fear-mongering that paints sharks as villains of the sea.
As Shark Week comes to a close, we at HWF think this might be the right time to shed some light on these ancient creatures of the deep.
Deep beneath the ocean waters swim one of the world’s oldest living species— sharks. Predating the dinosaurs by 200 million years, sharks have roamed the seas for over 400 million years, surviving five mass extinctions! To better understand the evolution of one of the ocean’s top predators marine biologists study the existing fossil records that take the form of shark teeth and scale impressions spanning hundreds of millennia. Fossilized teeth can provide an astonishing amount of evidence about the lives of prehistoric sharks— from their environment, to their diet, to their size. Since sharks shed thousands of teeth throughout their lifetime, these fossils are abundant. The oldest confirmed shark fossils are a set of scales found in Siberia that date back to 420 million years ago!!!
Check out this interactive timeline from the Discovery Channel to learn more about the evolution of sharks!
Unlike other fish, whose skeletons are made of bone, sharks are one of the elasmobranchs (a subclass of marine animals that also includes skates and rays) whose structure is made of cartilage— the firm but supple material that is found in the human ears and nose. Cartilage weighs much less than bone and offers sharks an advantage when it comes to speed, agility, and energy conservation in the water.
Though most people conjure an image of a wide-mouthed, sharp-toothed human slayer (thanks, in part, to the popularity of the Steven Spielberg’s Jaws, whose star, the Carcharodon carcharias aka a great white shark fits this description) the reality is that over 400 different species of sharks exist and the diversity among them is widespread. From habitats, diets, and personality to shape, color, and size, the variance among different families of shark species is vast.
Of the 440 species known today, the largest (whale shark) measures 60 feet (18 meters) while the smallest (dwarf lantern shark) can fit into the palm of your hand. Though immensely popular, great white sharks actually make up a very small percentage of the world’s sharks. Yet the fascination with them and fear of them seems to persist so long as the occasional human attack can be reported. Although publicity about shark attacks can be great for generating fear and popular headlines, humans are not a preferred food for sharks. Most large sharks prefer to eat marine mammals like seals, otters, and sea lions while other filter-feeders eat plankton, krill, and fish eggs from the water around them.
Most shark attacks occur when a swimmer either looks or smells like a common prey species and has been mistaken for food. It is relatively rare for sharks to attack a swimming human being, but when dressed in a wetsuit or when spearfishing, it is not unreasonable to be mistaken for a seal or a bleeding fish. As media stories and television programming continue to promote sharks as the villains, conservation efforts become increasingly difficult. In 2013, National Geographic estimated that over 100 million sharks are being killed each year— a staggering number that promises to have a major impact on future marine ecological systems if the pattern continues. While sharks are being vilified on television and in movies, individuals are taught to fear them and illegal shark fishing can continue without much social concern.
Perhaps it is time to reframe this inaccurate characterization of these magnificent creatures. Sharks do not pose a threat to human life unless humans encroach upon their space. Even then, the likelihood of a shark attack is extremely low. According to data from the Florida Museum of Natural History, sharks spark approximately 82 unprovoked attacks around the world each year, with just eight of those resulting in death. Which means that your odds of dying from a shark attack are 1 in 3,748,067!
These 10 shark facts from the Smithsonian’s Shark Girl might help illuminate some of the awesome and impressive qualities that sharks have.
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