Facts about Sharks
Sharks have been around for a very long time, over hundreds of millions of years in fact! And surprisingly there are still missing facts about sharks and information about this species that we do not know! While many of us may be familiar with some shark species, there are over 400 of them in total. Ranging from the tiny 8-inch dwarf shark right up to the 60-foot long whale shark.
Sharks are the apex predators at the top of their marine food chains, and they are vital within the ocean’s ecosystems to help regulate the populations of species below them. Recent research shows that a massive depletion of sharks has cascading effects throughout our oceans ecosystem.
To help you learn more about our beloved shark species, (and when better than during Shark Week?!), we have put together these awesome shark facts!
Is a Shark a Fish?
So first things first, are sharks mammals or fish? This may seem like an easy question but it does tend to catch a lot of people out. So what is the answer? Sharks are fish, not mammals. Sharks belong to a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins.
How many Species of Shark are there?
There are around 440 known shark species in the world. Some species are more famous than others, such as the iconic Great White Shark featured in Jaws – for better and for worse. Scientists believe that there any many more species yet to be discovered.
Where do Sharks Live?
Sharks can be found in all five of Earth’s oceans: the Atlantic, Indian, Pacific, Arctic, and Southern. Some sharks can also be found in freshwater lakes and rivers. As an example, the bull shark has been known to travel great distances up the Amazon River.
Unlike most other animals, sharks are not territorial by nature. This means that they tend to change their habitat often. One of the biggest factors when determining where a shark will migrate to next is the water temperature.
Sharks are sometimes classified by the surface temperature of the water they inhabit. The three major classifications are temperature, polar and tropical.
Tropical Sharks: Such as the hammerhead shark and the nurse shark, both inhabit ocean regions near to the equator.
Polar Sharks: These sharks live near the polar ice caps and have adapted to survive in the frigid waters which are just above freezing point. Some examples of polar sharks include the Greenland sleeper shark and the black dogfish shark.
Temperature Sharks: Inhabit the areas between the polar and tropical regions. The larger temperature sharks, such as the great white shark and the large basking shark will venture out of the temperate oceans and migrate to tropical waters. The smaller temperature sharks are unable to handle such drastic changes in water and therefore stay within regions where the temperature is more comfortable for them.
What is the Life Expectancy of a shark?
While the answer is unclear, it has been estimated that the whale shark, which is the largest of the shark species, can live up to 100 – 150 years old! Many of the smaller shark species are known to live to at least 20 – 30 years, but this fact still remains unclear. Some scientists believe to have had found Greenland sharks around 400 years old!
How fast can a Shark Swim?
I am sure that I don’t need to point out that most sharks are able to out swim you! But the Shortfin Mako Shark takes the medal! The Shortfin Mako shark is the fastest species of shark and can swim up to an amazing 56mph, that’s over 100kph! Pretty impressive?!
What is the Biggest Shark in the World?
The Shortfin Mako shark has the speed, but which shark species takes the gold for the biggest shark in the world?… The whale shark! With the name to suit, a whale shark can grow to a staggering 18 meters (60 feet) in length. Take a look at this chart of shark sizes to help put different types of shark into proportion.
Did You Know?
Sharks predate the dinosaurs by over 200 million years. The largest known species of shark, C. megalodon, might have reached a maximum length of 67 feet.
What is the Smallest Shark in the World?
Already listed within our 10 smallest animals found in the ocean, the smallest shark in the world is the Dwarf Lantern shark. This tiny shark species is only 15 cm long, that’s 6 inches small! It could easily fit into the palm of your hand!
Can Sharks Swim Backwards?
The pectoral fins of a shark are not able to bend upwards like that of a fish. This limits a sharks swimming ability to a forward motion only, meaning that sharks cannot swim backward or stop suddenly. If a shark needs to move backward, it uses gravity to sink backward rather than swim. However, there are a few species, which include the epaulette shark, which is known to “walk” backward.
Will Sharks Drown if they Stop Swimming?
The fact that sharks must keep moving in order to survive was once widely thought to be true, but it isn’t. So will sharks drown if they stop swimming? No. Although sharks obtain oxygen for breathing from the water that flows over their gills, many have adapted to doing this while they are still. Most sharks can rest on the bottom and pump water over their gills. The endangered Australian grey nurse shark can hang out almost stationary in the water for ages. They are often seen resting in groups.
What do Sharks Eat?
Sharks are carnivorous and eat fish (including other sharks), seals, mollusks, crustaceans and other marine mammals. Other types of sharks, such as the whale shark and the basking shark, feed on tiny plankton or krill. Sharks have a very acute sense of smell which also allows them to be able to detect blood in the water from many miles away. Despite their fearsome reputation as ruthless predators, sharks are much more likely to be killed by humans than the other way around
How much do sharks eat in a day?
Some shark species tend to hunt all of the time. As an example, the Great White shark is always on the hunt! This type of shark eats around 11 tons of food a year! For a comparison, we humans eat on average half a ton of food each year. The Blue Shark is known as a glutton, it will eat until it regurgitates and then goes right back to eating! Most types of sharks will eat a meal every couple of days. If necessary, sharks are able to go for a few weeks without eating at all. Just like people and most other animals, a shark is able to store extra energy as fat, for use later when food is limited.
Do all Sharks Lay Eggs?
Some sharks are oviparous, which means they are able to lay eggs. Other sharks are viviparous which means they give birth to live young. Within these livebearing shark species, some have a placenta just like human babies, whilst other sharks do not. In the cases where there is no placenta, the shark embryos are able to get their nutrition from a yolk sac or unfertilized egg capsules within the yolk. For the tiger shark, things are pretty competitive. The two largest embryos consume the other embryos of the litter!
How do Sharks Reproduce?
All sharks reproduce by using internal fertilization, though, with the male shark using his “claspers” to grasp the female then he releases sperm. The sperm is then able to fertilize the female’s oocytes. The fertilized ova are packaged in an egg case and then eggs are laid or the egg develops in the uterus.
Sharks mature slowly and only reach a reproductive age between 12 to 15 years. This combined with the fact that many shark species only give birth to one or two pups at a time. Meaning that sharks have great difficulty recovering after their populations have declined.
Soon after they are born, shark pups swim away to fend for themselves. They are born with fully-fledged sets of teeth and are therefore able to feed and live all by themselves.
How many Teeth do Sharks have?
So how many pearly whites to our sharks have? Well, that depends on the shark species. Some species of shark only have a few dozen teeth, whilst others can have thousands! We think the biggest shark in the world may take the price with an outstanding amount of around 3000 teeth!
Sharks teeth don’t actually have roots, and because of this, they fall out after about a week. Obviously, sharks aren’t swimming around toothless! But this is due to them having replacements arranged in rows, so when a tooth falls out, a new one can move in within one day in order to take the older tooth’s place. Sharks have 5 – 15 rows of teeth in each jaw, with the majority of shark species having five rows.
Which shark has the biggest teeth?
The prehistoric Megalodon was the largest shark to have ever lived. These sharks teeth could grow up to seven inches long! Relative to size, the Cookiecutter shark has the largest teeth. Although this shark species is rather small, it uses its large teeth in its round mouth to take cookie sized bites from the flesh of its prey, many of them being larger marine creatures such as dolphins.
How Strong is a Shark’s bite?
Astonishingly, the bite of a shark can generate up to 40,000 pounds of pressure per square inch. That’s a hell of a bite!
Can Sharks Smell?
Yes, sharks have amazing smelling abilities! So much so that a shark’s sense of smell is so powerful that some shark species can detect a drop of blood in an Olympic sized pool.
Can Sharks Detect Movement in the Water?
Yes, they can! Sharks can detect movement in the water because they have a lateral line system along with their sides. This lining system helps different types of sharks find prey and navigate around other objects at night or when there is poor visibility within the water. The lateral line system is made up from a network of fluid-filled canals hidden beneath the shark’s skin. The pressure waves in the ocean water around the shark can vibrate this liquid. This is then transmitted to jelly in the system which then transmits to the shark’s nerve endings where the message is then relayed to the brain. Pretty cool huh!?
How many Bones does a Shark’s Skeleton have?
So how many bones does a shark’s skeleton have? Hmm… This is a trick question! Sharks do not have bones! Being a cartilaginous fish, shark skeletons are made completely out of cartilage. This is the same material that is found in our human nose and ears!
What are a Shark’s Main Predators?
These apex predators are known to be at the top of the food chain, but the sad truth is, us humans are hands-down the biggest threat and danger to sharks. People are the ones responsible for killing millions of sharks every year. There are other animals known to eat sharks, these include, killer whales, crocodiles, and even larger sharks.
Which Shark is the most common?
Out of the different types of sharks, the ocean whitetip is the most common shark. This large shark is numerous in both the Atlantic and Pacific oceans. Out of the smallest shark species, the spiny dogfish ranks the most common with millions found in the North Atlantic.
What is the most Dangerous Shark in the World?
The great white shark, more commonly referred to as the “Great White,” has been reported to be involved in more attacks on humans than any other shark.
What is the Population of Sharks in the World?
It seems to be too difficult for experts to estimate the population numbers of sharks since there are so many different species spanning such a large geographic area. However, it is certain that overall shark numbers are on the decline due to the many threats they face in the wild. Experts estimate that around 100 million sharks are killed by people every year.
Humans are their biggest threat as sharks continue to be eaten as seafood in many areas around the world. Both commercial and recreational fisheries are also believed to be responsible for the reduced populations of shark species.
Loving these great shark-related posts from Ocean Scuba Dive? You might also like to read these;
- Facts about Great White Sharks
- Facts about Whale Sharks
- Facts about Tiger Sharks
- 15 Most Endangered Sharks in the World
- International Whale Shark Day
- Save our Sharks from Extinction
- Adopt a Whale Shark
- Adopt a Great White Shark
- Adopt a Basking Shark