Diving with sharks is an unbelievable experience. But the more shark facts we know, the more special it becomes to see these incredible creatures in our oceans. You don’t have to be a marine biologist to learn about sharks, so here are 10 facts about sharks that every diver should know.
#1 – Sharks have survived 5 mass extinction events
Just the fact that sharks have been inhabiting our oceans for 400 million years is amazing. To give you a bit of perspective, humans as a species have only been on earth for around 200 000 years. Sharks have survived 5 mass extinction events.
The last mass extinction event was about 65 million years ago when dinosaurs were killed into extinction. Sharks however survived and then thrived in the oceans.
#2 – Humans are a shark’s biggest predator
Sharks are feared in many cultures around the globe. Not only do we kill sharks out of fear, with shark nets, but we also kill sharks for food. In many cultures shark is eaten in a variety of ways and shark body parts are used for many purposes like shark fin soup.
It has been estimated that humans kill in the region of 100 million sharks on an annual basis.
#3 – There are 500+ different shark species
When you think of a shark, you most likely think of the fins and the sharp teeth, great whites for instance. But there are more than 500 species of shark spread all across the world. They come in all shapes and sizes but most have in common things like cartilaginous skeletons, big livers, and specific sensory systems.
From the hammerhead shark to the goblin shark, and everything in between, there are hundreds of amazing sharks out there all unique in their own way.
#4 – Some sharks eat their siblings in the womb
One of the most interesting shark facts is that during pregnancy grey nurse shark embryos survival literally depends on how fast they can develop. The most developed embryo will feed on it’s siblings. This is a reproductive mechanism known as intrauterine cannibalism.
#5 – Zambezi shark-like freshwater
The Zambezi shark has been spotted in lagoons and rivers, often kilometers inland. They prefer murky water for hunting and freshwater water systems often have murkier waters, especially where rivers meet the ocean.
#6 – Shark fin soup is popular in eastern cultures
Shark fin soup is extremely popular in countries like China. It has been said that drying shark fins cause them to become noodle-like in texture. Unfortunately, the popularity of shark fin soup has led to horrible overfishing and shark finning practices where sharks fins are cut off before they are thrown back into the ocean.
Finning leads to the death of millions of sharks every year.
#7 – Whale shark can be up to 12 meters in length and weigh 19 tons
Whales sharks might be the biggest sharks, but they are also very docile. They feed their massive bodies by feeding on plankton that they filter out of the ocean water with their many rows of teeth.
If you ever have the opportunity to dive or snorkel with a whale shark you will be amazed at how gentle they are, and how fast they can swim away if they decide to.
#8 – Sharks don’t have bones
Sharks are a subclass of Chondrichthyes and belong to the family Elasmobranchii. Basically that just means that they have no bones in their bodies and that their whole skeleton is made up of cartilage. This particular class of fish contains more than 600 species including sharks, rays and skates.
Because cartilage is lighter and more flexible it helps with their movement and abilities as apex predators. Their lightweight and flexible cartilage skeletons help them conserve energy as sharks are almost constantly on the move.
#9 – Sharks have a sixth sense
Sharks have many of the senses that you do: Smell, taste, sight, feeling, and hearing. Sharks have exceptional eyesight, they can smell one part blood in a million parts of water. They also have a sixth sense that makes them the exceptional predators that they are.
Sharks can detect electricity that is emitted by all living things, even if it’s very low levels of electricity. They have electro-receptors located within their snout, numbering in the hundreds to thousands. These electro-receptors are called the ampullae of Lorenzini. The ampullae of Lorenzini can pick up smell electrical fields emitted by their prey and other living creatures.
#10 – Sharks do not prey on humans
Contrary to popular belief, sharks do not prey or actively feed on humans. Even though shark incidents on humans do occur, it is almost always more of an investigation by the shark than an attack. Sharks have senses that make them experts at identifying their prey, but sharks will often bump into potential prey and take a bit to determine if it really is prey.
Unfortunately for sharks (and also humans that have been attacked by sharks), a shark bite even if just to determine if what it is biting is really prey, can cause severe injuries and even death. Surfers are often misidentified by sharks as they resemble the silhouette of a turtle or seal from below the surface. The only real way for a shark to know if something is food or not is to bump into it or worst case scenario have a bite.
Luckily sharks don’t mistake humans for prey very often. Especially when diving with full scuba gear sharks can quite easily make the deduction that we are not food.
Leave your favorite shark facts in the comments if you notice that we’ve missed out on any cool ones.