Frequently Asked Questions
The most-asked questions about sharks.
What exactly are sharks, and how do they differ from other fish?
Sharks are a group of cartilaginous fish meaning their entire skeleton is made of flexible cartilage rather than hard bone. They belong to the class Chondrichthyes, which also includes rays and skates, and they've been swimming the oceans for roughly 450 million years, predating the dinosaurs.
How many species of shark exist, and what's the most iconic one?
Scientists currently recognize around 500 to 650 species of shark depending on how recent genetic research is tallied. The great white (Carcharodon carcharias) is the most widely recognized, but fans of the hobby often point to the whale shark as the gentle giant and the hammerhead for its unmistakable head shape.
Where do sharks live, and can they be found in freshwater?
Sharks inhabit every ocean on Earth, from the sunlit surface to the hadal trenches near the seafloor, and some species like the bull shark and the freshwater river sharks of Southeast Asia do venture into rivers and lakes. Temperature, salinity, and prey availability largely determine which species show up in a given region.
Do sharks have bones, and how does that affect their body?
No—sharks are built entirely on a cartilage framework, the same flexible tissue found in your nose and ears. This keeps their bodies lighter and more flexible in the water, but it also means they lack the dense skeletal structure that bony fish rely on for support.
How do sharks detect prey, and what's electroreception?
Beyond sharp smell and lateral-line pressure sensing, sharks possess tiny ampullae of Lorenzini on their snouts that detect the faint bioelectric fields emitted by living muscle. This lets them locate a buried ray on the sandy bottom or a wounded fish hiding in murky water.
How long can a shark live, and is there a record-holder?
Most common species live anywhere from a few decades to around 70 years, but the Greenland shark (Somniosus microcephalus) has been estimated to reach 250–400 years, making it the longest-lived vertebrate known to science. Fans of the topic often cite this as the single most mind-blowing fact about the group.
Are sharks actually dangerous to humans, and how common are attacks?
Unprovoked shark attacks on people number roughly 30–50 per year worldwide, and the vast majority are non-fatal, making a shark bite far less likely than a lightning strike or a vending-machine accident. Biologically, most species are simply too small or too cautious to pose any real threat to a human.
What's a good starting point for someone new to shark biology?
A solid first step is learning the three main body plans—lamniform (great white, mako), carcharhiniform (reef, bull, tiger), and squaliform (thresher, dogfish)—because that framework makes every other species easier to slot in. From there, a documentary on the great white followed by a short read on hammerhead electroreception tends to hook most newcomers.
What are some notable 'moments' in shark science that fans love to cite?
The 2012 satellite-tagging of a great white named Bruce off South Africa, the 2020 genetic study pushing Greenland shark age past 400 years, and the 2019 discovery of a new deep-sea species in the Pacific are all frequently referenced milestones. Each one reshaped public understanding of shark behavior, longevity, or biodiversity.
Where can I see sharks up close without touching a tank?
Cage-diving operations in South Africa, Australia, and the Bahamas let you float in a steel frame while great whites or tiger sharks pass within a few meters, and many large public aquariums (like the Monterey Bay Aquarium or the Okinawa Churaumi Aquarium) house species from reef sharks to whale sharks in open exhibits. For a zero-risk option, a live-stream from a shark-research station is surprisingly close to the real thing.