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How Do Scuba Divers Avoid Shark Attacks?

Diving in the turquoise sea, amongst the coral reefs, meeting tiny fish and the adorable turtles, and visiting some of the most interesting locations underwater is a thrilling experience.

However, most sea lovers and scuba divers have several fears and hesitations before diving. One of the most feared factors is an encounter with deadly marine creatures, specifically sharks!

Did you know that there are 70 to 100 shark attacks on humans annually? This fact explains the concern of most divers.

If you are a scuba diver and fear shark attacks, you have stumbled upon the right place. In this article, you will learn about shark behaviors, how to avoid a shark attack and what to do if you see a shark while scuba diving.

Why Do Sharks Attack?

To prevent yourself from being a shark attack victim, it is essential to understand why could a shark attack in the first place? Moreover, it is important to study the behavior of sharks to find ways to avoid their attacks.

Sharks attack for various reasons; however, most are due to provocation. If a diver feeds or grabs the shark or accidentally follows one, it may attack as an instinctive defense response.

If the attack is unprovoked, then it must have happened due to confusion or curiosity.


A ‘confused’ attack occurs when sharks mistake humans with their prey. Although, sharks do not consider humans as food. Sometimes, humans resemble their prey, and this might result in multiple attacks.

Such confusion is common between great white sharks and surfers. If a surfer is on the surface lying on the surfing board, they may resemble a seal. Despite having an excellent vision, great white sharks may attack because their eyes tend to roll back when they are about to attack.


Sharks are curious about their environment, just like any other creature. They tend to investigate their surroundings using their mouths. A shark may bite if it can’t distinguish the diver as a human.

The bottom line is sharks attack mainly for two reasons – curiosity or confusion. They rarely attack humans due to aggression. They attack when they perceive evident danger, such as a human attacking them.

What to Do If You Encounter a Shark While Scuba Diving

If you have watched films about sharks, you must have noticed that they get portrayed as savage monsters who brutally kill their prey. However, this is not true; they have only been depicted as such to add an element of excitement. Sharks are nothing like that and are curious marine creatures.

If you encounter a shark, it is important to know what precautions to take to avoid a shark attack. Essentially, seeing a shark precedes a shark attack. Hence, if you encounter a shark, follow the steps given below.

1. Remain Calm and Stay with Your Dive Buddy

Sharks tend to close in and observe divers due to their curious nature; after being assessed, they swim away. It is extremely rare to see a shark, but stay calm and stick with your dive buddy if you do.

Humans look larger in water due to their diving gears. If you stick close to your diving partner, you will look even bigger. Your presence may not be confused with a prey. Sharks stay in the local area sometimes because of fishing activities.

They get easy meals when they locate themselves closer to the fishing activities.

2. Maintain a Respectful Distance

It goes without saying, any creature respects you if you respect them. Do not try to provoke them by grabbing or harassing them.

As nurse sharks, leopard sharks, and horn sharks usually swim sluggishly close to the seafloor, divers try to approach them and tend to touch them. As a defense, the shark may bite, not aggressively but as a warning to fend the diver, who it considers as an aggressor.

Therefore, it is best to maintain a respectful distance when you encounter a shark.

3. Do Not Swim Away Rapidly

When a prey feels the presence of its predator, they move away swiftly.

Sharks do not consider humans as food. Therefore, if a shark is near you, it will certainly not attack you directly, perceiving you as its food.

If you swim away rapidly, you confuse the shark, and it may perceive you as its prey. You cannot outswim a shark for sure, so stay where you are and do not make any sudden movements to scare or confuse the shark.

Let it explore the surrounding, and it shall go away sooner than you expected.

How Do Scuba Divers Avoid Shark Attacks?

Now that you are aware of what precautions to take, let’s explain how to avoid a shark attack when scuba diving.

Be Attentive

The key to dive in any zone inhabited by different creatures is to be attentive. As you have entered their habitat, they attempt to defend themselves and their territory, sometimes in unpredictable ways. Therefore, if you are attentive, you will be aware of the dangers and which areas to avoid.

If there are steep drop-offs or sandbars, chances are sharks may be lurking, as it is easier for them to hunt. You may find a shark near the surface of the water too. Therefore, it is extremely crucial to pay attention; you will minimize the chances of being attacked.

Don’t Dive at Certain Places or Certain Times

It would be best to avoid diving at certain places or times because of the chances of meeting a shark. Firstly, they hunt at dawn or dusk. Hence, you should avoid diving at those hours as they may confuse you as prey.

Make Yourself Look Big or Small

Making yourself appear bigger or smaller depends on two main factors. If the shark is not encircling you, then it has no interest in you. Stay put and attempt to curl yourself, presenting yourself as harmless; get closer to your dive partner or the reef.

If the shark gets curious and starts circling you, you should stretch yourself and extend your hands above your head; this will make the shark aware of your size and deter an investigative bite.

Choose Your Scuba Gear Carefully

Sharks prey on smaller fish, and the fishes have shiny scales. Hence, it would be best if you choose your diving suit wisely. You do not want to attract a shark because it is confused by the color of your suit.

Avoid wearing jewelry as it shines and glimmers and it may attract sharks. Select the color carefully; wear black or dark blue, and avoid wearing high contrasting colors.

Don’t Dive Alone

Sharks, because of their predatory behavior, are likely to attack divers who dive alone. If you dive with a buddy or a group, the chances of being attacked by a shark get significantly reduced.

Avoid Being on the Surface

Things on the water’s surface are often sick, dead, or debris that can attract small fish. Therefore, sharks tend to hunt close to the surface, and anything on the surface will attract them.

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So avoid being on the surface of the water. If you have to be on the surface for some reason, try to keep your head underwater to see if a shark is approaching you.

Watch Out for Warning Signs

Sharks do not generally give warning signs. However, if they do, then watch out for any agitated behavior. If a shark is making jerky movements, entering fast bursts of speed, lowers its pectoral fin, and makes exaggerated side-to-side head movements, it is most likely feeling threatened or stressed.

If you notice this behavior, try to be as subtle as possible and stop doing any movement or activity that may get perceived as threatening.

Maintain Eye Contact

Tiger sharks and many other types of reef sharks only attack if they have the element of surprise. Therefore, if you maintain eye contact with the shark, you will be making it clear that you can see the shark.

Avoid Swimming in Murky Water

Swimming in murky water is inviting trouble. It is difficult to watch out for sharks looming below. Moreover, they will not be able to differentiate you from prey. Therefore, it is best to avoid murky water at all costs.

Dive Only If You Have Training

Last but not least, you should only dive if you have the necessary training. Scuba diving requires formal certification, and only a professional can teach you how to deal with situations such as a shark attack.

Types of Shark Attacks


You can avoid shark attacks when you are aware of the reasons that can provoke them. Here are the types of attacks.

Provoked Attacks

Provoked attacks are when humans touch sharks. In addition, if divers try to grab them or feed them, sharks attack in defense.

Unprovoked Attacks

  • Hit and Run: In murky waters, sharks mistake human movements for their prey and attack. They bite once, and as they realize its not food, they swim away.
  • Sneak: In deeper waters, victims may not see the shark approaching them, and due to low visibility, it may perceive a diver as prey.
  • Bump and bite: A curious shark encircles the diver, and to identify it, it bumps into them and then bites.

What Are the Chances of Seeing a Shark While Diving?

Chances of seeing a shark while diving depends on various factors. If you dive during a specific time or in a specific zone, it may increase the chances of seeing a shark.

Similarly, if you dive during the breeding season, you are likely to encounter a shark.

If you have taken all the precautions and chosen a time and spot that is less likely to have sharks, your chances of avoiding a shark are increased.

In numbers, the chances of getting attacked by a shark are one in four million. Therefore, you should just enjoy your dive and not worry much about being attacked.

In fact, sharks hardy ever attack scuba divers.

Why Do Sharks Not Attack Scuba Divers?

The chances of being attacked by a shark during scuba diving are minuscule. The reason is that scuba divers interact with sharks; they make their presence more prominent. While surfers and swimmers cannot be easily differentiated from prey as they are on the surface of the water.

Moreover, sharks don’t consider humans as food. They are aware of humans and only attack when they feel threatened or confuse people with prey.

Final Thoughts

Sharks are natural predators and not monsters of the deep blue sea. Unlike what they are perceived in movies, as always hungry savage monsters, they are just curious creatures who want to explore their environment and make sure that it is safe.

If you are still afraid of sharks when you go for your next dive, just remember, there are about 500 different species of sharks, and only 30 of them have reportedly attacked humans.

Sharks only attack if they sense provocation. If you respect them, they will respect you too and not attack you.

My unbounded love for the oceans and everything it has to offer motivated me to pursue my passion and become a professional scuba diving instructor.

I keep reading, exploring, and learning more about scuba diving and the underwater world all the time, so I’m excited to share my knowledge with fellow scuba enthusiasts and hopefully contribute a little to your development as a diver. I want people to fall in love with the oceans with as much passion as I have. Read more about me here.

5 Potentially life Saving Tips When Scuba Diving With Sharks

Scuba diving with Sharks

Scuba diving with Sharks

Scuba diving with sharks can be both exhilarating and terrifying, but maintaining your composure is key to staying safe and enjoying these majestic creatures.

Keep in mind that the majority of shark attacks on humans are simply the result of them mistaking you for another animal.

These cases of mistaken identity can make you a statistic and give sharks a bad reputation.
But, again, by knowing what to do and what not when scuba diving with sharks, you can fully enjoy the experience.

Scuba Diving With Sharks is an amazing experience. Photo Credit: Willy Volk.

Remember, too, that the majority of sharks you’ll see on a scuba dive will keep their distance from you and behave non-aggressively.

Other sharks may instead be curious and approach you. If you do encounter a shark that begins exhibiting (aggressive) behavior, how you respond will make the biggest difference with regards to the outcome of your encounter.

Continue reading for five basic guidelines when it comes to safely scuba diving with sharks.

No Shiny Things Allowed when Scuba Diving With Sharks

Any scuba gear that’s brightly colored, shiny, or flashy in any way should be avoided when swimming in an area that could have sharks in it.

Shiny materials can attract sharks that end up mistaking you for a fish with shiny scales glistening against the rays of sunlight in the water. Stick with dark or matte metals, as well as black or blue wetsuits and gear.

Always Stay Calm When Scuba Diving With Sharks

It’s vitally important that you remain as calm as possible when scuba diving with sharks, especially since erratic movements can actually get a shark’s attention and provoke it.

Therefore, swim gracefully and calmly, just as you would if you were only surrounded by schools of small fish and coral. This will ensure your safety as you observe the sharks in their natural habitat without disturbing them or drawing attention to yourself. Follow the scuba code of conduct and you’ll be safe and sound.

Never Spearfish Around Sharks

Spearfishing around sharks is a bad idea, as it will draw attention to you, especially as the blood comes out of the fish you’re catching. If you begin Spearfishing without sharks in the area, but your activities draw them in, it’s best to let go of whatever you have caught and head back to the surface and onto your boat.

Swim with Purpose to the Right Areas

If you spot sharks in the water, you want to avoid the water column and the surface, as this is where the majority of sharks will hunt. Swim with speed and purpose to the bottom of the dive site or to the reef. After your scuba dive adventure is over, you should do the same to get out of the water.

Swim with purpose and enough speed to move to the surface, and then exit the water as quickly as possible if there are sharks in the water. This doesn’t mean that you should ignore the safety stop or the maximum rate for a safe ascent.

Don’t Follow Sharks

Always respect sharks and give them plenty of space. Do not, no matter how tempting it may be, pursue a shark from behind, as he may turn around, viewing you as a predator, to attack you in self-defense.

It doesn’t matter how badly you want that great photo or video clip; just let the shark go on its way.
Always follow up advice and local requirements when it comes to scuba diving with sharks.

Use solid judgment and common sense and you’ll enjoy scuba diving with sharks without any problems.
Remember that scuba diving with sharks isn’t a risky venture as long as you know how to behave around them.

What are your thoughts on scuba diving with sharks? Would you like to do so or would you pass on the opportunity? Let us know in the comments below.

This article is written by RUSHKULT, the online booking platform for Scuba Diving. Visit the RUSHKULT platform to book your next Scuba Dive training, guided trip, and accommodation.

Everything You Need to Know About Shark Diving

Before starting to dive you probably had a different opinion about sharks and especially about sharks and humans. Now that you’re addicted to breathing pressurized air, you realize how awesome it is to see and dive with sharks. If you’re in between these two phases, you’ll soon realize that sharks are very nice creatures, far from being dangerous, and very fun to dive alongside.

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Ready to dive with sharks? Read on to learn what you need to know before getting in the water.

Table of contents

Types of sharks

Sharks come in all form of shapes and sizes (almost). There are more than 500 different species of sharks in our oceans and every year scientists discover new species. You can dive with most of them. Some require a bit more attention than others, but divers have been with them in the water a number of times.

Let’s have a look at the various types of sharks.

Great White Sharks

The most famous one, at least for the number of movie appearances.

The Great White Shark is one of the biggest sharks. It can grow up to 20 feet (6 meters) and weighs up to 2 tons. You can find them in temperate and tropical waters, from the Gulf of Mexico to the Mediterranean Sea, from South Africa to Australia, from New Zealand to Alaska and across the entire Pacific Ocean.

Sharks are the most famous predators in the ocean. Their hunting behavior is fascinating. Seeing them in the water is one of the top dives every adventurous diver wants to do. Remember that you are in front of a machine that evolution didn’t touch for millions of years, just because they are perfect hunters.

You can dive and free-dive in Great White waters with or without a cage. It just depends on how you approach the shark. Diving close to a hunting area or attracting them with tuna heads could be really dangerous without a cage. To dive safely with them, it is mandatory to know their behavior. For this reason, always dive with an expert guide and you will enjoy the most adrenaline-filled encounter in the ocean.

A Great White Shark in Mexico. Photo Credit: Elias Levy

Photo Credit: Elias Levy

Whale Sharks

The biggest shark out there, they can reach up to 42 feet (12 meters) in length but are absolutely harmless.

Whale Sharks are filter feeders, which means that they eat only planktonic organisms and small fishes.

Imagine jumping into the water, turning your head back and seeing a bus-like fish that is swimming gently to you. Encounters with Whale Sharks are astonishing.

Behind their size is a hidden yet sophisticated GPS system that allows them to migrate thousands of miles in the open ocean.

Snorkeling or diving with them is a great adventure. The Ari Atoll in the Maldives is one of the most famous sites where you have a high chance of seeing a Whale Shark.

Get on board and look at the surface of the ocean. A giant shadow is coming close to you. Grab your fins and mask and jump into the water.

Font view of a Whale Shark in Maldives. Photo credit: Gregor Kervina

Photo credit: Gregor Kervina

Tiger Sharks

Tiger Sharks are named for the dark, vertical stripes found mainly on juveniles. As these sharks mature, the lines begin to fade and almost disappear. They are among the biggest sharks in the ocean at 20 feet (6 meters) in length.

Although they are big hunters, they are mainly scavengers. This means they eat dead organisms and actually a nearly limitless menu of diet items.

As majestic and slow swimmers, an encounter with a Tiger Shark is amazing, not only for its size but also for its elegance.

If you are brave enough to dive with this incredible creature, we can suggest many places in the world where you can find them and of course crazy diving guides that are eager to bring you in front of a Tiger Shark!

A Tiger Shark in Bahamas. Photo credit: Albert Kok

Photo credit: Albert Kok

Hammerhead Sharks

Up to 20 feet (6 meters) in length, Hammerhead Sharks are the easiest to recognize thanks to the particular head shape, reminiscent of a hammer. The strange shape allows them to see almost 360° and use a highly specialized detector of electric and magnetic fields. This means they can move in the blue water of the ocean, without any reference points, yet remain perfectly oriented. As one might surmise, they are unbelievable hunters.

Hammerhead Sharks are distributed in all tropical waters. Among the best locations for hammerhead diving are the Galapagos, Bimini Island, Costa Rica, Hawaii, the Maldives and Indonesia.

Just take your time and think about a great dive surrounded by hundreds of Hammerhead Sharks!

Close up of a Hammerhead Shark

Bull Sharks (Zambesi)

The Zambesi Shark is one of the most aggressive species of shark together with the Great White and Tiger Shark. A common myth about Bull Sharks is that they have the highest level of testosterone in the entire animal kingdom.

This shark has more testosterone than a whole team of rugby players. Zambesi Sharks, as they are called in South Africa, are also well known for their ability to swim in freshwater rivers and even reach lakes many miles inside the coast.

Are you brave enough? If so, take this challenge and follow us underwater to look for the Zambesi Shark! Take your equipment and jump in the warm water of Mexico, the Bahamas, Kenya, India, Thailand or Indonesia.

A black and white picture of a Bull Shark. Photo credit: Brook Ward

Photo credit: Brook Ward

Oceanic Whitetip Sharks (Longimanus)

A beautifully shaped shark!

The Longimanus is an easily distinguishable species due to its long and robust, paddle-shaped pectoral fins. Although the most distinctive features are the white tips on the first dorsal, pectoral, pelvic and caudal fins. The adults can grow up to 13 feet (4 meters). They are rarely observed in a group. Rather, they are most often solitary and in open waters.

The Oceanic Whitetip Sharks are famous for their curiosity, swimming very close to divers or following boats and others animals, mostly due to their search for food. They eat almost everything, but prefer pelagic fish.

Diving with Longimanus Sharks is easy, the Red Sea and tropical waters are the home-water of this majestic shark. For any information related to how to dive with this shark, just contact us!

An Oceanic Whitetip Shark or Longimanus. Photo credit: Isaias Cruz

Photo credit: Isaias Cruz

Nurse Sharks

While pelagic species, including sharks, must keep moving in order to breathe, Nurse Sharks can remain motionless, lying on the seafloor under tabular corals or inside caves. They are mainly active during the night, allowing divers to easily enjoy an encounter during the daylight hours. Nurse Sharks are bottom dwellers, feeding primarily on sea snails, crustaceans, molluscs and other small fish that are sucked into and then crushed in the mouth. These sharks also possess sensory barbells that protrude from their upper lip, allowing them to feel the presence of their prey in the environment and mainly under the sand.

They are present in the warm waters of all oceans, from the African coast to the paradise of the Maldives, Australia and the tropical waters of the Atlantic and Pacific oceans.

A Nurse Shark resting on a sandy bottom

Cow Sharks (Sevengill Sharks)

Cow Sharks are considered one of the most primitive sharks. Their skeletons resemble those of ancient extinct forms. Their most distinctive feature is the presence of a sixth or seventh gill slit, in contrast to the five found in all other sharks. They can grow up to 16 feet (5 meters) in body length and are very good hunters. They live in the deep and cold water of all the oceans from New Zealand to South Africa and from the Atlantic Ocean to the Mediterranean Sea. Diving with Cow Sharks is not that easy due to the rarity of encounters in coastal and shallow waters, but in some places you have a higher chance of spotting these sharks. The kelp forests in South Africa and California are, for example, the ideal habitat for seeing this prehistoric hunter!

A Cow Shark swimming in a kelp forest

Reef Sharks

Caribbean Reef Shark (Carcharhinus perezii)
Blacktip Reef Shark (Carcharhinus melanopterus)
Grey Reef Shark (Carcharhinus amblyrhynchos)
Whitetip Reef Shark (Triaenodon obesus)

Reef Sharks are the apex predators of the reef ecosystem. Caribbean, Grey, Blacktip and Whitetip Sharks are the most common species that you will find in the reefs of all oceans. These sharks usually don’t exceed 10 feet (3 meters) in length. However they are great hunters, feeding mainly on small reef fish, crustaceans and molluscs.

Spotting Reef Sharks is very easy. They are abundant around the reefs of all tropical waters in the Atlantic and Indo-Pacific Oceans. Just reach your favorite tropical place and dive as much as you can to enjoy an encounter with a school of Reef Sharks. It will turn a normal dive into a great dive.

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A Whitetip Reef Shark resting on the reef. Photo credit: Sandro Lonardi

Photo credit: Sandro Lonardi

Other sharks

Of course the ones mentioned above are only a small percentage of all the sharks species. I haven’t forgot the Lemon Shark, Blue Shark, Basking Shark and all the other many species you can find in the ocean.

A Basking Shark

Shark attacks

Being attacked by a shark is quite rare, but could happen. Do you know that every year there are about 60 confirmed shark attacks around the world? But why do sharks attack? First of all, you have to know that, fortunately, you are not on their menu. Most of the time they bite us because they are curious or frightened. Attacks can be provoked or unprovoked, and observations have shown that there are potentially 6 factors as reasons for shark attacks:

  • Food in the water
  • Confusion of senses
  • Competition
  • Animal personality
  • Conditioning
  • No respect

That doesn’t mean that if you swim close to a shark you will be attacked by it. In fact, we can name 18 things more dangerous than sharks. You just have to remember that there is always a hazard, because they are wild animals.

If we compare sharks with other animals we find out, for example, that mosquitoes transmit diseases like malaria to more than 700 million people every year, and around 2 million of them die. And what about dogs? In the USA, dogs bite 368,000 people per year and in the last 6 six years, there was an average of 31 fatal attacks per year.

We are often frightened by sharks, but did you know that two seemingly harmless creatures are among the most poisonous of the planet? Most pufferfish contain a toxin in their body that could potentially kill 30 adults. But nothing compares to the poison of the small golden poison dart frog, whose poison is contained in the mucus that covers its skin. One gram of this toxin can potentially kill almost 6,000 people!

To have an idea of the risk of shark attacks take a look below:

  • Total: 2,899
  • Fatal: 548

Only 5-15 of attacks annually are fatal.

Now think that more or less 79 million sharks are killed each year by humans. So who is really more dangerous?

A shark attack. Photo credit: Isaias Cruz

Photo credit: Isaias Cruz

Shark conservation

Sharks are stunning creatures. They have existed for almost 400 million years. It is incredibly frustrating and sad to know that they are disappearing. Why? Because of humans of course. Shark finning, bycatch, habitat destruction and overfishing are the main causes of their endangerment.

The demand on shark products is very high. For example, shark fin soup is a delicacy, especially in China. It is thought that this soup is a natural remedy for boosting sexual potency, enhancing skin quality, preventing heart disease and lowering cholesterol, but different studies have shown that this is incorrect. Other in-demand products are shark cartilage, shark liver oil, shark teeth and jaws, shark leather and even manta ray gills.

Shark fins. Photo credit: Nicholas Wang

Photo credit: Nicholas Wang

Why sharks are so important

Sharks are defined as “top predators.” The role of a top predator is to keep the balance in the complex food web of the marine ecosystem. A number of scientific studies demonstrate that depletion of sharks results in the loss of important fish and other organisms that keep the ecosystem healthy. If you’d like to continue to enjoy the beauty of the ocean while diving, it is your duty to save the sharks!

What you can do to help these animals

You should avoid buying the products mentioned above. If there is no demand, it is unnecessary to kill all these creatures.

Ecotourism can also help sharks as well as other marine life. The definition of ecotourism is: “Responsible travel to natural areas that conserves the environment, sustains the well-being of the local people, and involves interpretation and education”.

A dead shark has less market value than a living shark. Scientific studies have shown that the fin of a dead shark on a restaurant menu brings in less money than a shark swimming in the ocean and attracting ecotourists. In this way, ecotourism has a massive impact on the protection of marine life.

So let’s go diving with sharks!

A whale shark

Shark feeding

Have you ever heard about shark feeding? While we are discussing ecotourism, we should mention that sometimes it is not easy to see sharks. This is because the number of them has decreased. Some frequently migrate and often their home range is huge. So to attract the sharks to one point, some divers feed them. There are different methods, like drifting bait and diver cages, feeding buckets and crates, or hand-feeding. There are many opinions about this practice, but without going into detail, only experts should do it, considering the risk. For example, a shark could become aggressive and even attack humans. It is also really important to avoid altering a shark’s behavior. If they used to migrate, they could stop because there is a new, permanent source of food.

In some countries, like Australia, shark feeding is forbidden.

Shark feeding (Great White Shark)

Sharks facts

Shark teeth are awesome

They can regenerate and change their teeth continuously during their lifetime, as we change between baby and adult teeth during our childhood. Sharks can lose more than 20,000 teeth, while we only lose 20 baby teeth. This strange strategy is very important to avoid broken teeth stuck on the jaw. It is not useful for the shark. A shark’s tooth shape is dependent upon its diet. There are four basic types of shark teeth that vary according to the diet of the shark: dense flattened teeth for crushing; needle-like teeth for gripping; pointed lower teeth for gripping and triangular upper teeth with serrated edges for cutting; and teeth that are tiny, greatly reduced and non-functional.

A close up on shark teeth

Shark sense: how to detect the hidden world

Sharks have a perfect set of sharpened knife-teeth to cut, crush and grip their prey, but what make them really formidable predators?

Imagine staying in a big room, completely dark, with your eyes closed, no smell, no noise, nothing, but you can feel the presence of someone. You can also understand the size and the movement of the other person and also predict the way the person is moving. This is one of the most important senses in the natural world: electroreception. In this way sharks can feel the presence of every organism around them and attack in the blue water of the ocean or under the sand with incredible precision and accuracy.

Close up photo of a sand tiger shark

Tonic immobility: do you sleep supine?

Sharks don’t but they will fall into a trance if they are supine. A trance is when a being is disconnected from his or her normal conscious state. Scientists think that it happens when a chemical is released into the shark brain to prevent panic. The brain is probably flooded with the neurotransmitter called serotonin. When the brain is overloaded, the shark falls into a coma-like state. When the shark is in the right position the serotonin concentration decreases and the shark returns to consciousness. The second hypothesis is related to electroreception. The coma-like state is attained by touching the area surrounding the eyes where the Ampullae of Lorenzini are located. The Ampullae of Lorenzini are the receptors that activate electroreception. It is thought that it may alter the electroreceptive sense of the animal with tonic immobility. After touching the shark it will start again to swim. The process is always reversible.

Two penises: a funny way to ensure the continuity of the species

Actually, male sharks have no penises. They have grooved organs to deposit the sperm into the genital duct of a sexually receptive female shark. These organs, called “claspers,” are developed from each pelvic fin (the paired fins located behind a shark’s belly). Because the pelvic fins are paired, so are the claspers. It seems they only use one at a time. Sharks are not perverted.

A Lemon Shark


This article was written by Mario Passoni and Luca Saponari – two marine biologists involved in several projects concerning ocean conservation and education.

Special thanks to Jim Hancock from the Maldives Whale Shark Research Programme, John Richardson from Shark Trust, Victoria Elena Vasquez, and the photographers who allowed us to use their stunning images in this article.




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