Sharks Can Smell a Drop of Blood from Miles Away
The most persistent shark myth floating around is that these predators can detect a single drop of blood from several miles away. This frightening tale has terrified swimmers for decades, but science tells a completely different story. Sharks cannot smell blood from miles away, and under optimal conditions, a shark can smell blood from a maximum of a quarter of a mile away.
Here’s the catch though – the shark cannot smell anything until the scent reaches its nostrils, and the wounded prey’s blood would first need to diffuse in the water, then the water would have to carry the blood to the shark for it to detect the scent. Many sharks can detect a single drop of blood in roughly an Olympic-sized swimming pool, which is still incredibly impressive without being supernaturally terrifying.
All Sharks Are Massive Man-Eating Monsters
Thanks to Hollywood blockbusters and sensationalized media coverage, many people picture sharks as enormous, razor-toothed killing machines. The reality is far more diverse and fascinating. Not all sharks are large and bulky like those in movies – there are actually more than 400 different species of sharks ranging from the tiny 8-inch-long deepwater dogfish to the massive 40-foot-long whale shark.
The basking shark has tiny teeth that it doesn’t even use for feeding, and the horn shark has molar-like teeth that it uses to crush hard-shelled prey. The world’s smallest shark, the dwarf lantern shark, can fit in the size of your hand. Some of the largest species, including whale sharks and basking sharks, are gentle filter-feeders that pose absolutely no threat to humans.
Sharks Actively Hunt Humans as Prey
Perhaps no myth has caused more unnecessary fear than the idea that sharks see humans as tasty meals. Humans are not food for sharks – the sharks involved in incidents with humans are often hunting for similar-sized prey like seals or dolphins, while the majority of shark species actually eat fish or invertebrates such as squid or clams.
Sharks have been around for much longer than humans (450 million years versus about 2 million years ago), and therefore evolved to eat prey like fish and marine mammals. Shark encounters are often a case of misidentification – a splashing surfer can look similar to an ocean animal, and some sharks will investigate with a nibble. Once it realizes it hasn’t captured its usual prey, the shark will often let go. Humans are not part of a shark’s normal diet as sharks usually feed on small fish and invertebrates, seals, sea lions, and other marine mammals. A shark attack will usually occur if the shark feels curious or confused.
Shark Attacks Happen All the Time
Media coverage might make you think shark attacks are common occurrences, but the statistics tell a dramatically different story. The 2024 worldwide total of 47 confirmed unprovoked cases is in line with the most recent five-year average of 64 incidents annually, with 7 confirmed shark-related fatalities last year, four of which were unprovoked – a number that aligns with the five-year annual global average of six unprovoked fatalities per year.
In the U.S., where the risk of shark attacks is highest, the chance of someone being killed by a shark during their lifetime is around one in four million. Americans are much more likely to be killed by other animals – the chance of being stung to death by hornets, bees and wasps is around one in 41,000, while fatal dog attacks happen to around one in 45,000. The global risk of being killed by a shark is around one in 28 million.
Sharks Have No Natural Predators
The image of sharks as apex predators with no natural enemies is only partially true. While sharks are at the top of the food chain, there are some exceptions. Orcas have been shown to eat mako, great white and other sharks by flipping them over to stun them. Also, larger sharks will eat smaller sharks – including ones of the same species!
Elasmobranch cannibalism can even happen in the womb – some species of shark, including sand tiger sharks and grey nurse sharks, will eat their siblings before they’re even born. Humans are sharks’ main predators, with millions of sharks being legally harvested for consumption, dying after being accidentally caught and released, or killed by illegal fishing operations each year.
All Sharks Must Keep Swimming or They Die
One widely believed myth suggests that all sharks must constantly swim to breathe and survive. While this is true for some species, it’s not a universal shark characteristic. Some shark species must swim continuously to breathe and survive, but not all do. The species that need to swim constantly are known as obligate ram ventilators, and include blue sharks and shortfin mako sharks.
Several species, including spiny dogfish and epaulette sharks, have small openings behind their eyes called spiracles, which pump water to their gills so they can continue breathing without swimming. Other species, such as bull sharks and lemon sharks, can use what’s called buccal pumping for breathing when stationary. This involves opening and closing their mouths to create enough water movement over their gills to respire.
Megalodon Sharks Still Exist in Deep Waters
The internet loves to fuel speculation about giant megalodons lurking in unexplored ocean depths, but science has definitively put this myth to rest. No scientific evidence supports that megalodon sharks (Otodus megalodon) still exist. These sharks are believed to have gone extinct roughly five million years ago and reached 18 meters (60 feet) in length.
White sharks were initially thought to be their closest living relative, but recent research suggests today’s mako sharks are more closely related! The absence of any credible physical evidence, combined with our understanding of ocean ecosystems and food chains, makes the survival of these ancient giants virtually impossible in today’s oceans.
Shark Populations Are Recovering and Out of Control
Some people believe that shark populations have fully recovered from decades of overfishing and are now dangerously high. This misconception has been fueled by increased reports of shark interactions with fishing boats. Research suggests the increase in shark depredation is likely due to several factors, including rebuilding of certain shark populations, increasing released and discarded catch of fish due to more restrictive regulations, shifting distributions of shark species due to climate change, and developing learned behaviors as sharks might be behaving differently as they learn to associate the sounds of fishing boats with easy meals.
The increase in shark depredation doesn’t mean that all shark populations have recovered or are out of control. Conservation efforts and implementation of shark fishing regulations have led to the rebuilding of multiple shark stocks, including those commonly blamed for depredation, but some are still far from being fully rebuilt. Select species of sharks are increasing in the United States, but around the world, shark populations face a genuine threat of extinction through overexploitation.
Only Three Shark Species Are Dangerous to Humans
While it’s true that most shark species pose no threat to humans, the common claim that only three species are dangerous oversimplifies the reality. Out of more than 480 shark species, only three are responsible for two-digit numbers of fatal unprovoked attacks on humans: the great white, tiger and bull. However, the picture is more complex than this suggests.
A number of other species have attacked humans without being provoked, and have on extremely rare occasions been responsible for a human death. This group includes the shortfin mako, hammerhead, Galapagos, grey reef, blacktip, lemon, silky shark, and blue sharks. These sharks are also large, powerful predators which can be provoked simply by being in the water at the wrong time and place, but they are normally considered less dangerous to humans. Out of more than 500 shark species, only 13 are known to bite humans “frequently,” which researchers define as biting humans 10 or more times.
Sharks Go into a Feeding Frenzy When They Smell Blood
Hollywood has popularized the terrifying image of sharks going completely berserk at the first whiff of blood in the water. This dramatic portrayal bears little resemblance to actual shark behavior. There’s a myth that sharks go crazy if they smell even a drop of blood, leading many people to be terrified of getting even a tiny cut while in the water. However, the truth is that sharks don’t go into a frenzy as soon as they smell blood. A few experiments conducted by brave individuals have proven this myth wrong.
Feeding frenzies do occur; however, they are typically caused by too many sharks competing for too little prey. The blood itself doesn’t trigger the aggressive behavior – it’s the competition for limited food resources that creates the chaotic scenes sometimes observed in nature.
All Shark Bites Are Fatal
The myth that shark encounters inevitably result in death has been thoroughly debunked by modern medical statistics and improved emergency response. More people die from bee stings or lightning strikes than by shark attacks. According to research, about 30 people die each year from shark attacks, which means a person has a one in 300 million chance of being killed by a shark. A shark attack most often occurs when a shark mistakes a person for a seal or other animal.
Most “attacks” on humans are mistakes due to poor water visibility or are inquisitive bites. This is why there are so many more bites than fatalities. There were no reported shark bites in any of the 26 Southern California beaches surveyed from January 2019 to March 2021, and of the millions of beachgoers around the world who swam in the ocean in 2018, there were only five shark-related human deaths.