Sharks Are Bloodthirsty
We usually picture a shark as a ferocious carnivorous monster straight out of Steven Spielberg’s Jaws—the great white shark, or Carcharodon. But in reality, not all of these fish devour meat.
For example, whale sharks, giant sharks, and pelagic megamouth sharks feed on plankton.
These gentle giants gather tiny crustaceans in their wide-open mouths and ignore larger prey, much like whales.
But there’s an even stranger case of shark pacifism—the bonnethead shark, or shovelhead shark. While it can’t be called a vegetarian, more than half of its diet consists of plant matter. It swims along the seabed, consuming crabs, shrimp, mollusks, and also algae.
Perhaps this is why the bonnethead shark is only about 1.5 meters (4.9 ft) long. If it ate meat, it would grow bigger and stronger.
Sharks Can Sense a Drop of Blood in the Ocean From Miles Away
It’s often claimed online that sharks can smell blood in the water from miles away and rush toward their prey like torpedoes. Supposedly, even a tiny scratch, a single drop of blood, can attract them. But that’s not entirely true.
This myth has some basis since most sharks have a pretty good sense of smell. They have nostrils on their noses, but these are used solely for detecting scents, not for breathing.
Studies on olfactory receptors show that the best sense of smell is not in the famous great white sharks, but in hammerhead sharks. However, hammerheads are more likely to use their sense of smell to find mates than prey.
A shark can indeed detect blood in the water, but not from a miles away.
Biologist Tricia Meredith from Florida Atlantic University found that sharks’ sense of smell is not supernatural. Tuna and rays have exactly the same level of olfaction, yet they don’t have the reputation of apex predators.
On average, a shark can detect one drop of blood in a billion drops of water, which is about the volume of a typical swimming pool. So if you cut your hand while swimming in one, a neighboring shark might find you.
However, there’s some doubt that sharks are highly attracted to human blood. Blogger and former NASA engineer Mark Rober conducted several experiments in the Bahamas, using his own blood, cow blood, fish oil, and urine to lure predators (just in case sharks had strange tastes).
In the end, the test subjects were much more interested in tuna oil than in mammalian blood. Apparently, marine cuisine is more familiar to them, and they haven’t had much opportunity to taste cows on the ocean floor.
All Sharks Are Large
When thinking of sharks, most people picture the great white shark, or Carcharodon, the predator from Jaws. In fact, there are over 400 different species of sharks, and they vary greatly in size, habits, and appearance.
The great white shark can grow up to 6 meters (20 feet) long and weigh almost 2,000 kg (4,400 lb). But there’s an even bigger shark—the whale shark, which can reach up to 20 meters (68.1 ft) in length. As mentioned earlier, it feeds on plankton.
However, the ocean is also home to truly tiny predators that could fit in the palm of your hand.
For example, the dwarf lanternshark only grows to 21.2 cm (8.3 in). There’s also the spined pygmy shark, about 28 cm (11 in) long, and the pygmy ribbontail catshark, which is around 23 cm (9.1 in). These are peaceful, shy fish that pose no danger whatsoever.
The dwarf lantern shark can even glow, thanks to photophores—special organs on its belly. This helps it swim and feed calmly during the day, as other fish looking up think it’s just a glint of sunlight passing by.
Sharks Flip Onto Their Backs Before Biting
In literature, there’s a claim that sharks turn on their sides or backs before biting. For example, in the novel Twenty Thousand Leagues Under the Sea, harpooner Ned Land uses this trait to time his strikes.
What’s my harpoon for? You see, professor, sharks are pretty clumsy creatures. To bite you, they need to flip onto their backs…
Jules Verne, Twenty Thousand Leagues Under the Sea
But this is a myth that could cost a shark hunter their life. Diver and photographer Valerie Taylor from the Royal Geographical Society of Australia filmed marine predators for almost 60 years. She observed their hunting of whales and other marine mammals and says sharks don’t need to flip over to bite.
In survival recommendations for military pilots, experts from the U.S. Air Force Academy also state that a shark can bite from almost any position. They advise crash survivors in the ocean not to rely on its supposed clumsiness.
Sharks Don’t Get Cancer
In collections of “incredible facts about nature,” it’s often claimed that these marine predators never suffer from cancer.
But unfortunately for these fish (and anyone rooting for them), that’s not true. Scientists have documented cancerous tumors in at least 23 species of these predators, including the great white shark.
The myth that these cartilaginous fish are immune to cancer probably originated from a 1983 study.
In it, scientists discovered a substance in shark cartilage that limits the development of blood vessels and, consequently, the growth of tumors. As is often the case, journalists exaggerated and concluded that if cartilage inhibits cancer and sharks are made of it instead of normal bones, they must be immune to tumors. But that’s not the case.
Shark Fins Are Extremely Beneficial
A widespread misconception suggests that various shark parts, such as their fins or cartilage, can cure different diseases, especially cancer. Additionally, they are believed to extend life, boost intelligence, improve potency, and enlarge any body parts you desire.
But this is just a myth. Regardless of what alternative medicine advocates claim, shark cartilage powder or shark fin soup does not cure cancer. Here’s what a shark researcher has to say about it:
Even if sharks didn’t get cancer, eating them wouldn’t cure it. It’s like eating Michael Jordan in hopes of becoming a basketball player.
David Shiffman, Oceanographer, University of Miami.
Moreover, shark fins, which mainly consist of the same cartilaginous tissue, have very little nutritional value. Consuming them is unlikely to improve your health in any meaningful way.
Additionally, researchers from the University of Miami discovered that some shark fins contain significant amounts of mercury and a neurotoxin called BMAA.
Fish are fine with this—they don’t care about such things. However, humans may develop degenerative brain diseases, like Alzheimer’s, Parkinson’s, and Lou Gehrig’s disease (ALS), as well as reproductive system issues.
Shark Fins Grow Back After Being Cut Off
This is false. While some species of fish can regrow lost tails and other body parts, sharks cannot. Their fins are made of cartilage and non-segmented keratinous rays, known as ceratotrichia, which are nearly incapable of regenerating. There are exceptions, such as whale sharks, which can heal even severe wounds, but this is rare.
So, when fins are cut off, the shark is doomed to die from starvation or even suffocation, as their gills can’t function without movement. The poor fish will literally drown in its own habitat.
In short, it’s not worth spending money on shark fin soup: it’s cruel, pointless, and wasteful. A good old perch soup is tastier and more nutritious.
Sharks Cannot Stay Still and Never Sleep
This claim contains a fair bit of truth. Most sharks indeed need to move for fresh water to flow over their gills. But that doesn’t mean they never sleep.
These fish apparently have the ability to swim while asleep. In this state, the shark’s brain rests, while the spinal cord keeps the body moving forward so that the respiratory system continuously receives oxygen from the water.
Greg Skomal, a biologist at the Massachusetts Division of Marine Fisheries, asserts that great white sharks can sleep or at least doze. In this state, they swim slowly forward with bulging eyes and open mouths.
Moreover, some species, such as reef, carpet, and lemon sharks, as well as the nurse shark, have learned to pull water through their gills by mouth, allowing them to sleep while lying on the ocean floor. They’re fine with that.
Sharks Are Loners
This isn’t always the case: some sharks are quite social. For example, lemon sharks often gather in groups, as it’s easier to hunt and safer together.
They somehow manage to communicate and even teach each other. Seriously, a fish that has figured out the easiest way to catch food can show this to its peers. Young lemon sharks follow adults, learning how to hunt and avoid predators.
Even the toughest and most fearsome sharks, like great whites, can feed together without disturbing one another.
These predators can even play together and socialize, establishing complex hierarchical structures within their groups.
Sharks Are the Biggest Threat in the Ocean
Thanks to horror movies, sharks are considered the scariest marine man-eaters. But statistics show that these fish don’t live up to the hype.
According to the Australian Museum of Natural History, sharks bite humans around 100 times a year. About 10 of these incidents are fatal. Mosquitoes, which transmit various diseases, kill more people in a day than sharks have killed in the last 100 years worldwide.
In fact, you are more likely to be killed by lightning than by a shark.
Sharks don’t hunt humans and don’t see them as a food source, so their attacks are rare and accidental. If anything, stray dog attacks result in twice as many fatalities—and encountering them is far more likely.
On the other hand, humans kill about 100 million sharks each year—for food and medicinal purposes (which don’t work anyway). So, it’s not us who should fear them, but they who should fear us.
Sharks Attack Because They Mistake People for Seals
There’s a myth that sharks kill swimmers for one simple reason: they mistake them for large pinnipeds. And when the predator realizes its mistake, it just spits out its catch.
However, this isn’t true, even though it sounds logical. Sharks often hunt seals and other marine mammals, but they don’t confuse humans with them. They use different tactics: when attacking, they decisively tear and devour the animal immediately, while they explore humans cautiously. Here’s what experts say about this:
I’ve observed more than a thousand attacks by great white sharks on sea lions. If they attacked people the same way they attack pinnipeds, they would rocket to the surface like torpedoes and tear the victim apart. But they approach humans slowly and nonchalantly.
—R. Aidan Martin, Director, ReefQuest Shark Research Center.
Sharks bite people not because they think they’re seals, but because that’s how they explore the world. Instead of touching unfamiliar objects like humans and primates do, these predators bite them. And even if a great white shark bites a diver out of curiosity rather than malice, the victim won’t feel any better.
There’s even a term for this—”exploratory bite.” Sharks frequently test even inedible things with their teeth to figure out what they are because they can’t feel them. They don’t have hands.
When a Shark Attacks, Punch It in the Nose
Just deliver a powerful hook punch to the shark’s nose, and the stunned predator will retreat—this is the advice that circulates on social media, often with variations. Some even suggest biting the shark yourself.
As martial arts masters (or someone else) once said: “If a fight is inevitable, strike first, brother.”
But hitting a shark is one of the dumbest things you can do. These fish are far less sensitive to pain than mammals, so you’re more likely to hurt a bear than a shark. Also, it’s very hard to deliver a damaging punch underwater, even if you’re a boxing champion, because water is much denser than good old air.
Moreover, sharks are apex predators in their environment, so they are not easily scared. Striking first could provoke the fish to retaliate, and it’s unlikely that a human would win such a fight.
Playing dead doesn’t work either, since sharks have an organ called the ampullae of Lorenzini. It allows them to detect electrical fields in the water, especially those created by the nervous system and muscles of living creatures.
So, to convince a shark you’re dead, you’d have to shut off your brain and spinal cord—something hard to do without dying for real. And sharks don’t mind eating carrion.
The only thing you can do when encountering a shark is to calmly swim away and get out of the water without provoking it. If it grabs you and won’t let go, your best bet is to stick your hand in its gills. Chances are slim, but it might help.
