The Great White Shark, otherwise known by their scientific name Carcharodon Carcharias, is one of the most famous types of sharks in our oceans. They breached the surface to fame in the Hollywood blockbuster, Jaws, and now circle on our screens for Discovery Channel's Shark Week. Found in cool and coastal waters around the globe, they are considered the ultimate apex predator of the sea. They can grow anywhere from 15 to 20 feet long and can weigh up to 5,000 lbs. While most of a Great White’s body is actually grey, it gets its name from its white underbelly. These torpedo-shaped creatures can swim up to 15 miles per hour. The Great Whites near Australia and South Africa have a reputation of being the boldest of their kind, breaching (jump out of the water) in order to attack their prey from underneath! But in recent years, the white sharks in Cape Cod waters have also been known to employ this attack method.
Hunting and Diet
The Great White has extremely powerful jaws, and its mouth is lined with rows of 300 triangular and serrated teeth. Its body is also lined with rows and rows of tiny tooth-like plaques called Denticles. White Sharks use their impressive sense of smell to locate their prey. On their nose, they have tiny jelly-filled pores called the Ampullae of Lorenzini. These pores are tiny organs that pick up weak electrical stimuli of animals, mostly prey nearby. They enjoy feasting on big, blubbery animals, such as whales, dolphins, sea lions, and seals. Some sharks even eat other species of shark.
Despite widespread misconceptions influenced by decades of movies and real-life horror stories, humans are not a shark’s meal of choice. The human body does not provide a Great White with enough protein or calories to sustain itself as these sharks are constantly swimming in order to stay alive. A high-calorie, high-fat meal like a whale can keep this kind of shark satiated for more than a month!
When it comes to hunting, Great White Sharks can detect a single drop of blood in 25 gallons of water. Some FIN-formation that is important to note before you hit the beach, is that splashing, kicking, or any sudden jerking movements send electrical stimuli through the water straight to sharks. Great Whites are the ultimate predator and have only one known predator of their own, the Killer Whale. But Killer Whales do not devour Great Whites, rather, they appear to only eat their livers. This particular kind of shark relies on its oversized liver to keep it buoyant as it needs to constantly swim, which is known as ram ventilation.
It is impossible to write an article about Great Whites without discussing attacks on humans. On average, there are 100-plus shark attacks every year around the world, and Great Whites are believed to be responsible for about ⅓- ½ of those attacks. Fortunately, most of these attacks are not fatal. Great Whites have been known to be very curious predators and like to do a taste test before they let go. In the cases of fatal attacks, it has mostly been mistaken identity; many times, swimmers can look like seals to the shark swimming below. There, swimming near seals isn't the smartest idea. Be Shark Smart when entering the water!
While the total number of Great Whites isn't definitively known, there was a recent survey done for the census for Marine Life that found that there are around 3,500 individual white sharks left. Scientists attribute the decreasing population to the sharks accidentally getting caught in fishing nets, and overfishing. Many sharks are also killed for their fins. They are now considered to be a vulnerable species, which according to the International Union for the Conservation of Nature, is one step away from becoming endangered.
How does this affect us on the Cape, you might ask? Like many of us, these sharks have become annual visitors to Cape Cod through the months of July through October. You can trace the origins of Great Whites in these waters back to the rebounding of the seal population. Fishermen always viewed seals as a hindrance, as they shared a common prey: fish. Prior to the Marine Mammal Protection Act of 1972, fishermen received $1 per caught seal, as they attempted to rid the waters of the competition. In the decades since Congress passed the law, the seal population has rebounded from near-extinction, and sharks have followed the trail of food to the Cape. This has paved the way for incredible shark research in our own backyard! The Atlantic White Shark Conservancy in Chatham provides funding and resources for the Massachusetts Division of Marine Fisheries Studies to study shark movements on Cape Cod. Scientists are now tagging and tracking them to get an accurate number of how many sharks are here seasonally.
Sharks play a critical role in maintaining a healthy and balanced marine ecosystem. While the media might portray them as dangerous man-eaters, we need to remember that the ocean is their home, not ours.
Photos: 1st- World Wildlife Foundation, 2nd/ 3rd- Atlantic White Shark Conservancy Instagram