There are some animals that humans seem to fear almost instinctively, down to our very DNA. Spiders and snakes are often mentioned when it comes to land. However, in the sea, there is one perceived supreme threat to humans: Sharks.
Sharks have been around a long time—longer than the current form of humans, in fact. Their evolution is such that they are nearly perfectly adapted to their environment. That makes them formidable prospects for a human to face.
The irony is that sharks don’t naturally prey on humans, and their reputation as vicious killers is largely undeserved. These interesting facts about sharks will explain why this is so. They will also show why the shark, like the ever-popular dolphin, is amazing, fascinating, and cool!
Everything about sharks is fascinating, and here are the facts to prove it.
Although shark attacks on people are relatively uncommon, an interesting statistic is connected to them. According to a report in National Geographic, 93% of all shark attack victims are males. This is more than likely because most surfers, fishermen, and swimmers happen to be male, at least traditionally.
There are at least 465 known different species of shark.
Hammerhead sharks look very unique, and they have gifts to go along with those looks. Their eye placement means that they might be able to see 360 degrees around them. This means that they see you, no matter which direction you come from—except for two.
Hammerhead sharks cannot see directly in front of their heads and directly behind their tails because of their eye placement.
Hammerheads, like most sharks, do have an additional weapon in their arsenal. They can detect electrical signals in the ocean better than most other fish through their 3,000 ampullar pores. This helps them to find food.
A biological ancestor, the Carcharodon Megalodon, was known to swim the waters of this planet some 16 million years ago. It was bigger than the biggest shark you might encounter today.
The meg is estimated to have been 55 feet long and may have weighed as much as 25 tons. If that is accurate, it would be the biggest predator to ever live on the planet.
We can tell how old a shark is a lot like we do a tree. Sharks develop rings on their vertebrae, a lot like trees develop rings in their trunks. We can therefore date a shark when we look at how many rings it has in its backbone.
They also have little growths on their skin that resemble teeth. These can also be thought of as scales, except that they develop something similar to enamel coverings. As sharks grow older, more scales appear, as the scales themselves don’t actually grow.
Speaking of teeth, sharks lose a lot of teeth over their lifetime. This begs a strange question: are there lots of shark teeth in the ocean? Scientists believe that there may be, and even if they do break down over time, they become a part of the silt that makes up the ocean floor. Sometimes divers find shark teeth, though, and that makes for intriguing neck jewelry.
Sharks don’t actually have the luxury of being able to lie still in order to rest. They remain semi-conscious at all times, in part because they also have to keep moving in order to survive.
Lantern sharks have an interesting way of lighting up their own lives. Like some other ocean life (octopi and some deep ocean fish), they employ bioluminescence to create an interesting underwater light show. It’s not because they need to see; rather, it attracts potential prey towards them, making hunting easier. Another reason might be to attract other sharks as mates.
Animals like snakes and sharks can be dangerous if you should encounter one, but they really are not out to get you. Sharks don’t really have a taste for humans, and the cases of shark attacks are far more sensationalized than they are likely. You only have a 1 in 3,748,067 chance of being attacked by a shark.
More people are killed by lightning strikes or fireworks each year, to put the number of shark attacks in perspective. Yet, you go outside every day, even on the 4th of July, and even during inclement weather.
The frilled shark has the longest gestation period of all sharks. It carries unborn young for three and half years.
It’s been mentioned that sharks don’t really sleep. Because of this, they can travel long distances, and larger species can go long periods without eating. A great white has been known to travel 2,500 miles in short shrift.
Sharks have astounded our knowledge of shark reproduction. A zebra shark was isolated in an aquarium in Australia for four years and then, in 2016, gave birth to three baby sharks. At first, scientists thought that the mother had stored sperm from a previous mating and then fertilized spontaneously after a time.
Later, it was discovered that the baby sharks only had DNA from their mother, suggesting that the reproduction had been asexual. At least one other shark had done something similar, this time in Nebraska.
Sharks share an interesting reproductive trait with some other animals, like cats. They can be impregnated by several male sharks, and their offspring in one “litter” can be from several “fathers.”
Although the blood detection prowess of a great white (or any shark) is often exaggerated, it does have an impressive ability to smell blood. Don’t believe the fantastic stories. At the very most, a shark—a great white in particular—can detect a drop of blood in a mass of water equal to an Olympic pool.
Many scientists say that it is even less—one drop in about 25 gallons. This ability is due to an enlarged olfactory organ. When it smells blood, it seems to trigger a feeding instinct.
What is truly impressive, though, is that sharks seem to be able to sense blood in the water at a great distance. Some studies suggest that if enough blood is in the water, a shark can detect it from almost five miles away. This is just another ability that makes it an apex predator, which eats 11 tons of food per year.
Despite its fearsome presentation, great whites are surprisingly lazy when it comes to eating. To explain: when a great white (and some other predatory sharks) come in for the kill, they will bite their prey and then retreat and wait. They prefer prey that is immobile, presumably bled to death, to avoid having to struggle to eat it.
Sharks have been observed to stop eating before they give birth. Their loss of appetite, we think, is to stop them from eating their own young when they are born. Talk about a fish with a singular purpose in life.
Another wild fact about sharks during pregnancy relates to the babies themselves. Some shark babies seem to be aware of their ocean surroundings even while unborn. Studies show that they emit an electrical impulse that can detect dangers to the mother or to themselves. They can slow their own gill movements or “breathing” if they detect threats.
The largest embryos mostly consume the rest of their sand shark litters before they are born. Scientists think that this allows larger young to be born with a greater chance of survival. So, sharks aren’t born predators; they are predators even before that.
Another way to tell a shark’s age is a bit more bizarre. Scientists have discovered that they can use a radiocarbon timestamp. This timestamp was found in sharks that were alive during the nuclear testing of the 50s and 60s.
These kinds of sharks can be found in rivers and lakes in Asia, New Guinea, and Australia. Meanwhile, bull sharks can swim in both fresh and saltwater.
Unlike whales (and humans), sharks have no biological way to vocalize. So you’ll never hear one coming unless its theme music is playing (you know the one we mean). All the better for being the silent hunter of the seas.
Lots of animals can’t do this, but it makes for more efficient slashing and gnashing of food.
Bull sharks are an exception to the bite and retreat rule. They tend to hold onto their prey once they bite. This may be an adaptation due to the environment. They are found in fresh and saltwater, which often means a murky playing field. Lesson: Once you have it in your grip, letting go of prey might not be the best idea.
In the modern era, the whale shark is the behemoth of the shark world, measuring an impressive 40 feet. It is the biggest fish in the sea, and the funniest part of their story is that they don’t eat people.
A whale shark feeds on plankton. It is, in fact, a filter feeder, which makes it unlikely to attack other fish, prey or people, at least not intentionally. They may sometimes scoop up an unwitting fish or two at that size.
Part of what makes sharks such excellent swimmers is that they are actually lighter and more flexible than their size and mass suggest. That’s because their skeletons are made from cartilage and muscle, which is half the weight of solid bone. That’s also why they can turn on a dime and accelerate like a racecar.
Shark skin as thick as six inches has been measured. They may have the thickest skin of any animal on earth, other than the sperm whale. So it’s no use insulting them. It will also take some effort to break the skin unless you have a sharp, pointed object.
Sadly, there is a huge market for shark meat, especially fins. In some parts of the world, shark fins are served as food, usually in a soup of sorts. The demand has led to overfishing of sharks, resulting in species being under threat.
In this way, humans are more of a threat to sharks than the other way round. People kill about 73 million sharks every year.
According to experts, one of the body parts that help sharks thrive in the water is their liver, which is unusually oily. Apparently, this helps them keep their balance in the water. Oil from the liver is also used in human medicine.
One shark known to scientists doesn’t actually bite its prey. The thresher shark uses its body, throwing itself against its prey to stun it or even kill it. It’s a case of nature employing the “take THAT!” strategy of food acquisition.
They have been around longer than our dinosaurs as we understand them. Scientists estimate that sharks have been swimming in our oceans for 450 million years. They claim seniority over dinosaurs by 200 million years—and they’re still here! That’s what makes them super-efficient as predators. They’ve had a lot of time to practice.
In the film Finding Nemo, the beloved character Dory sings “just keep swimming,” which is really applicable to most shark species. Sharks need to keep moving in order to “breathe.”
Only one known shark species doesn’t do this. The nurse shark is thought of as lazy, mainly because it does not move all the time, hardly ever migrates, and doesn’t seem to mind not eating as much. What kind of shark doesn’t want to eat?
When food is scarce, sharks make use of that previously mentioned oily liver as a reserve for essential nutrients. Oil is drawn from the organ to hold the shark over until the next meal, especially during long migrations.
Sharks reach maturity at between 12 and 15 years. There is a broad range of lifespans for sharks. Some live more than 100 years! Scientists found one Greenland shark that they aged at 272 years.
Lemon sharks will often migrate to where they were born in order to have their own young.
One theory suggests that sharks and humans had a common ancestor, based on being jawed animals. We split from each other around 420 million years ago. The shark got the better deal when it comes to jaw strength; a great white measures around 4,000 pounds per square inch of pressure with its bite. Humans tip a measly 200 psi.
Some sharks have a unique ability to warm their own brains through the retina of their eyes. This is needed when they drop to depths where the temperature is much lower than at higher levels. It also helps them to focus visually and mentally in the water.
Baby sharks are born with a full set of teeth in order to start hunting immediately. They also usually have to defend themselves against members of their own litter and even their mom. It puts that children’s song in perspective, doesn’t it?
The shark got the better deal when it comes to jaw strength; a great white measures around 4,000 pounds per square inch of pressure with its bite. Humans tip a measly 200 psi.
Most have five rows, and some have up to 300 at any one time. Sharks never run out of teeth, despite losing them at a phenomenal rate. It seems that they just grow more. A shark loses thousands of teeth in its lifetime.
It helps them to glide through the water. The genius of design at work.
According to the UK tabloid paper The Sun (credibility unverified), some strange things found in sharks’ stomachs include a bulldog, an entire suit of armor, a bottle of wine, a cannonball, a tire, and even a polar bear.
Sharks can propel themselves out of the water, just like breaching whales. Some have been seen rising ten feet above the surface.
The spotty pattern of a whale shark is as unique as a human fingerprint.
Shark mating rituals often involve some biting. Male sharks bite females, and then they separate for a while when a female is impregnated.
Epaulette sharks crawl along the ocean bed’s bottom on their four fins. They are adapted to low oxygen conditions in the water.
One species of shark is thought to have been around in the megalodon times and is still here! The goblin shark is an odd-looking shark, often referred to as a living fossil.
Sharks, unlike most other fish, do not lay eggs. Instead, the eggs hatch inside the mother’s body. The hatchlings or “pups” emerge from the mother fully formed.
Sharks have pretty good hearing. They can hear potential prey from almost half a mile away.
The blue shark can birth 135 pups in a single go. Most sharks don’t do that, so it’s very impressive numbers.
You can eat shark meat in Europe without knowing it. Order a fish ‘n chips, and chances are you’re eating spiny dogfish, which is a shark.