A Blue View: Predatory Skills of the Great White Shark

So you consider yourself a shark expert? We’re challenging your knowledge of these infamous apex predators with our collection of jaw-some great white shark facts.

Published July 21, 2015

carcharodon-carcharias

Image via WikiCommons.

  1. These teeth weren’t made for chewing. The great white might be known for its mouthful of chompers—about 300, to be exact—but it doesn’t chew its food. These apex predators tear their prey into mouth-sized pieces that they then swallow whole.
  2. Their vision is clear as day—even at night. The great white’s retina is comprised of two areas: one adapted for day vision and another for low-light and night vision.
  3. Females aren’t exactly the maternal type. Mommas typically birth about two to 10 pups, which measure about 4 to 5 feet long and 77 pounds. These newborns don’t need any help adjusting to their new world—they immediately swim away from the mother to hunt on their own. Good thing, too, because Mom isn’t interested in parenting. In fact, it’s not unheard of for females to eat their own offspring. 
  4. Pups aren’t even an option until females are 33 years old. It takes a while for great white sharks to reach sexual maturity. For males, it’s about 26 years; for females, it’s about 33.
  5. Good luck attacking their eyes. The great white has a unique defense mechanism to protect its eyes. When it attacks, it rolls its eyes back into its head, shielding it from its prey’s claws or barbs.
  6. Don’t underestimate their hearing. You might not be able to spot the ears on a great white, but the two tiny openings behind and above its eyes provide powerful hearing. Its ears contain cells that sense small vibrations in the surrounding water.
  7. Humans aren’t on the menu. Despite the stigma surrounding these huge apex predators, there are only around five to 10 great white shark attacks each year. Researchers believe that, in these cases, the sharks are only taking a “sample bite” out of curiosity, swimming off after realizing their prey doesn’t appeal to their palate.
  8. Your chances of surviving an attack are high. If a great white wanted to have you for dinner, it would. But since it lacks a taste for humans, more than 70 percent of attack victims survive. The shark typically realizes its mistake and puts a stop to snack time.
  9. Their coloring provides the perfect camouflage. The blue-gray coloring on the top of a great white allows it to blend in with the ocean floor when viewed from above. Its white belly provides similar camouflage, enabling it to blend in with the sunlight shining around it when viewed from below.
  10. Great white shark populations are considered vulnerable. Great white sharks are listed as vulnerable by the International Union for Conservation of Nature (IUCN), and the World Wildlife Federation claims they’re decreasing in numbers due to years of being hunted by humans for fins and teeth. This species also tends to be a victim of bycatch, frequently caught by commercial fisheries by accident.

Episode Transcript

The great white shark has long been feared as one of the sea’s deadliest apex predators. Averaging 15 feet in length, weighing upward of 5,000 pounds and sporting about 300 serrated teeth, it’s hardly a wonder these creatures have been given a notorious reputation.

But it’s not just their size and razor-sharp pearly whites that make them such successful hunters. The great white shark is armed with six—yes, six—acute senses that have evolved to perfection over millions of years.

Smell is the great white’s strongest and most accurate sense. It can detect a teaspoon of blood in a swimming pool’s worth of water. Its super-sensitive sniffer is the result of an organ called the olfactory bulb—and the great white’s is the largest of all the sharks, making it a dangerous detective in an ocean full of prey.

While its ears may be tiny—appearing as just two small openings above and behind the eyes—these powerful organs add two highly valuable skills to the great white’s predatory portfolio: First, the ears can sense even the tiniest vibration in the surrounding water; and second, they can respond to gravity, informing the shark of its position in the water, head up or down, right-side up or upside down.

As if it needed more weapons in its anatomical arsenal, the great white shark’s vision is also superb. Its retina has evolved to accommodate both light and dark environments, with two distinct areas for day and night vision. The eyes are even equipped with a handy defense mechanism—if attacked, they can roll backward into the socket, protecting them from harm.

Then there’s touch. Fish and sharks have a unique sense of touch through what’s called the lateral line, which extends along the middle of the body from tail to head. The lateral line consists of cells that can perceive vibrations in the water, allowing the great white to sense the direction and intensity of movement made by prey. Sea lions, seals, small whales and other shark snacks risk detection from almost three football fields away.

Not to be forgotten, there’s taste. Sharks are adventurous eaters; they’ll try just about anything. However, despite the popular misconception that great whites and other sharks actively seek out humans, we’re not on their menu. They have taste buds inside their mouths and throats that enable them to identify the food before swallowing—which is generally what they’re doing in those rare instances when they have attacked a hapless human.

The great white’s sixth sense is worthy of superhero status: Using electromagnetic sensors, it can find prey by their electrical fields. In its snout, are a series of cell-filled pores called Ampullae of Lorenzini. These organs can feel the tiny electromagnetic fields generated by other animals. Not only can they help the great white find its next meal; they also help it navigate the vast ocean by following an electrical “map” of the magnetic fields that intersect along the Earth’s crust.

Up to one-half of annual shark attacks are attributable to great whites—a fact primarily due to the species’ size, power and feeding behavior. That said, the majority of attacks are not fatal, and the likelihood of a shark attack is still miniscule. In 2014, there were just 10 shark-related fatalities worldwide. By contrast, humans kill approximately 100 million sharks annually, threatening many species through overfishing, bycatch and illegal poaching.

The great white might be a legendary hunter, but Earth’s true apex predator remains our own species.

To learn more about great white shark behavior and why it’s important to protect this remarkable species, visit aqua.org/ablueview.

A Blue View is produced by the National Aquarium for WYPR. For the National Aquarium, I’m John Racanelli.

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