If Shark Week is leaving you hungry for more and you’re looking to learn about the ocean’s most misunderstood creatures, here are some common misconceptions and frequently asked questions to sink your teeth into!
Are Sharks Attracted to Human Blood?
Human Blood Doesn’t Trigger a Feeding Frenzy
Luckily for those of us who are injury prone, this is not true! Sharks can smell human blood; however, it will not send them into a feeding frenzy or increase the likelihood of an attack. Sharks are more interested in the scents and chemical cues associated with their natural prey than they are in human blood.
Do Sharks Sleep?
Sharks Rest Differently Than We Do
Not in the typical sense. Sharks can rest, but many species need to stay moving in order to keep oxygen-rich water flowing over their gills.
How Sharks Breathe
This form of breathing is called ram ventilation. Other sharks use a different method called buccal pumping, where they actively move water through their mouths and over their gills, allowing them to remain still while continuing to breathe.
Ram Ventilation
The shark swims forward with its mouth open so water continuously passes over its gills. Sharks that rely heavily or essentially on ram ventilation tend to be active, open-water swimmers.
Examples include
- Great White Sharks
- Mako Sharks
- Whale Sharks
- Hammerheads
Buccal Pumping
Allows a shark to actively draw water into its mouth and pump it across its gills. This means the shark can breathe while remaining still. It’s particularly common among bottom-dwelling sharks.
Examples include
- Nurse Sharks
- Wobbegong Sharks
- Angel Sharks
- Catsharks
Ram Ventilation + Buccal Pumping
Some sharks are capable of switching between the two methods. They can pump water over their gills while resting and use ram ventilation when swimming.
Examples include
- Lemon Sharks
- Reef Sharks
Great White Shark
Catsharks
Lemon shark
What Do Sharks Feel Like?
Shark Skin Is Like Sandpaper
Sharks are very smooth if touched from nose to tail. However, if touched in the opposite direction, they have a rough, sandpaper-like texture.
Tiny Teeth Cover a Shark’s Skin
This texture is caused by the dermal denticles that make up their skin. These denticles vary in shape from species to species and aid in hydrodynamics as sharks move through the water. In other words, they reduce drag and help sharks move more efficiently.
How Good Is a Shark’s Eyesight?
Sharks Have Excellent Low-Light Vision
Sharks have excellent eyesight, including impressive vision in low-light conditions. Many sharks have something called a tapetum lucidum behind the retina, which helps with night vision by reflecting available light.
From left to right: thresher shark eye, lantern shark eye, lemon shark eye
Detecting Movement and Contrast
Their vision is particularly good at detecting contrast and movement in the water, helping them navigate their environment and locate prey.
How Can I Avoid a Shark Attack?
Be Aware of What’s Happening Around You
There are several things to keep in mind when spending time in the ocean. Avoid areas where people are actively fishing or where baitfish are present, as this activity can attract sharks. Use caution around river mouths and after heavy rain, when water conditions may be cloudy or murky.
Reduce Unwanted Attention
Reducing excessive splashing and swimming in groups rather than alone can help reduce unwanted attention. Most importantly, pay attention to local beach warnings and remember that sharks are wild animals living in their natural environment.
Why Are There So Many Shark Teeth on Beaches?
Finding shark teeth along the shoreline is a common and exciting experience for beachgoers. The abundance of shark teeth on beaches is the result of how sharks continuously replace their teeth throughout their lives.
Sharks Constantly Replace Their Teeth
Shark jaws contain multiple rows of teeth. Whenever a tooth is lost, another tooth moves forward from behind to take its place.
Some shark species can lose up to 30,000 teeth during their lifetime. With thousands of sharks constantly shedding teeth, millions eventually settle on the ocean floor before waves and erosion wash many of them onto beaches.
CAN YOU NAME THE SHARK SPECIES BY ITS TEETH?
The size and shape of sharks teeth vary depending on what their prey consists of. For example, before eating a crustacean or a mollusk, a nurse shark uses its short, round teeth to crush the creature’s shell. Alternatively, a shark that chases and grasps its prey has long, pointed teeth.
Test your knowledge of sharks and their teeth by taking our 10 question quiz.
How Many Different Species of Sharks Are There?
There are over 500 species of sharks, and most are very different from the large predators that typically come to mind.
Sharks Come in Many Shapes and Sizes
Sharks have evolved a remarkable variety of adaptations, including:
- Bioluminescent species such as the cookie cutter shark and kitefin shark.
- Filter feeders like the basking shark, whale shark, and megamouth shark.
- Walking sharks, such as the epaulette shark, which can move across shallow reefs.
- Deep-sea species like the Portuguese dogfish, which have been observed at depths of nearly 12,000 feet.
Despite their reputation, most sharks pose little or no threat to humans. Only around 30 species have ever been involved in recorded attacks on people.
“Most shark species represent little or no threat to humans… even the species we consider dangerous actually bite people very infrequently.” – Dr. Carl Meyer, University of Hawaii
Why Do Sharks Attack Humans?
Shark attacks are extremely rare and are usually the result of mistaken identity rather than intentional predation.
Mistaken Identity and Curiosity
From below, a surfer or swimmer can resemble natural prey such as a seal, sea lion, or sea turtle. Murky water, splashing, or reflective clothing and jewelry can make identification even more difficult. Spearfishers may also attract sharks because they are competing for the same food source.
Sharks are naturally curious animals and often investigate unfamiliar objects with their mouths. While this can result in a bite, it is not always intended as a predatory attack.
How Do Sharks Give Birth?
Sharks reproduce in several different ways depending on the species.
Three Types of Shark Reproduction
Some sharks, including lemon sharks and bull sharks, are viviparous, meaning they give birth to live young called pups that develop inside the mother. Others, such as great white sharks and tiger sharks, are ovoviviparous. Their eggs hatch inside the mother’s body before the pups are born live. Species like the epaulette shark and many catsharks are oviparous, laying protective egg cases that are attached to rocks, coral, or seaweed until they hatch.
How Long Do Sharks Live?
A shark’s lifespan varies greatly depending on its species. Most shark species live approximately 30 years.
Shark Lifespans Vary by Species
- Spinner sharks and blacktip sharks typically live around 10 years.
- Whale sharks can live between 70 and 100 years.
- Greenland sharks are the oldest known vertebrates, living for up to 400 years.
The Greenland shark’s extraordinary lifespan is believed to be the result of its extremely slow metabolism, which is an adaptation to the cold Arctic waters where it lives.
Why Are Sharks Important?
Sharks play a vital role in maintaining healthy marine ecosystems.
Sharks Are Keystone Species
As a keystone species and apex predators, sharks help keep ocean food webs balanced by removing weak, sick, and injured animals. This helps reduce the spread of disease and supports healthier fish populations.
Sharks also regulate prey populations. For example, tiger sharks help control sea turtle numbers. Without sharks, sea turtles could overgraze seagrass meadows, damaging valuable habitats that support marine life and contribute to oxygen production. Healthy shark populations are essential for healthy oceans.
“Not only are sharks not a threat, but they’re also helpful. They are beneficial. We are better off with healthy shark populations.” -Dr. David Shiffman
What Threats Do Sharks Face?
Although sharks have survived for hundreds of millions of years, many species now face significant threats caused by human activities.
Shark Finning
One of the greatest threats is shark finning, where sharks are caught, their fins are removed, and the rest of the body is discarded back into the ocean. The fins are commonly sold for shark fin soup.
It is estimated that this practice kills roughly 10,000 sharks every day.
Bycatch
Sharks are also frequently caught as bycatch, meaning they become accidentally entangled in fishing gear intended for other species. Along with sharks, dolphins, whales, sea turtles, and seabirds often drown after becoming trapped in fishing nets or lines.
Sport Fishing
Sport fishing tournaments can also impact shark populations by targeting the largest individuals, which are often mature females capable of producing future generations.
What Can We Do to Help Protect Sharks?
1. Knowledge Helps Replace Fear With Understanding
Research! Understanding combats fear and brings awareness to the threats sharks face.
2. Make Shark-Friendly Choices
Sign petitions and encourage lawmakers to advocate for conservation-focused bills. Avoid products that contain shark meat or shark-derived oils, such as squalene, and choose sustainable seafood whenever possible.
3. Support Shark Conservation
Support nonprofits dedicated to shark and ocean conservation by donating, participating in local events, volunteering, or engaging with and sharing their content on social media.
4. Spread the Word About Sharks
Teach others about sharks and encourage them to care about one of the ocean’s most important groups of species. The more people understand sharks, the more likely they are to want to protect them.
5. Meet a Shark
Experiencing what it’s like to dive with a shark in the wild can be a life-changing adventure that puts into perspective how beautiful and fascinating these animals really are. You will be able to connect with nature and come home with priceless memories, new knowledge, increased confidence, and an appreciation for the ocean’s most misunderstood apex predators.
Join us in the Philippines to see thresher sharks Dec 8-20, 2027 for a liveaboard and land based scuba diving adventure. Image captured by Jamie, Executive Director, Shark Angels Dec 2026 in the Philippines onboard the Atlantis Adventurer. This image has not been photoshopped or manipulated in any way. It was shot using an iphone in a Sport Diver Sealife Housing.
Written by Caroline Smith, University of North Carolina at Wilmington, 2026 Graduate, Bachelors of Science in Marine Biology and Shark Angels Intern.
For more info on our Earn Your Wings Mentorship Internship Program click here.