Sharks are amazing marine animals that first appeared on earth about 420 million years ago, which makes them 189 million years older than dinosaurs! That’s pretty old, especially considering that humans didn’t show up on earth until just 200,000 years ago.
There are over 465 different types of sharks, which range in size from six inches to 60 feet long. Sharks are very diverse creatures, which means there are lots of differences between different species. For example, some sharks are extremely fast, while others are very slow. Some female sharks lay eggs, while others give birth to live baby sharks, which are called “pups.”
These amazing facts about sharks will show you just how diverse they are!
Biggest and Smallest Sharks
The smallest shark is the dwarf lantern shark, which is just six inches long and can fit in your hand. Dwarf lantern sharks have an organ called a “photophore,” which lights up their bellies and fins to help camouflage them in bright, shallow water and attract food in deeper, darker waters.
The largest shark is the whale shark, which usually grow to about 45 feet long – longer than the longest school bus! Whale sharks have been known to reach lengths of up to 60 feet, and they can weigh up to 47,000 pounds. You would think that a shark this big would eat the biggest prey it could find, but whale sharks actually feed on plankton, which are microscopic plants and animals that drift in the water and measure bout 7/1000ths of an inch and smaller! That’s kind of like a human eating specks of dust. To trap the plankton, the whale shark swims through the water with its mouth open, and the tiny plankton get trapped in the shark’s “filter pad.” Can you imagine how many of these teeny tiny creatures they have to eat every day?
Fastest and Slowest Sharks
The fastest shark is the shortfin mako, which can swim as fast as 60 miles per hour, about as fast as you travel in a car on the interstate or highway. Mako sharks can leap out of the water and have even landed in boats, which probably really freaked out the passengers!
The slowest shark is the Greenland, which lives in very cold water. These sharks swim slower than one mile per hour. Compare that to your normal walking speed, which is probably about 3 miles per hour.
Highest and Lowest Number of Pups in a Litter
Shark babies are called pups, and they’re born in one of three ways: their mother lays eggs in the ocean and the babies hatch in the water, the mother develops eggs that hatch inside her body and then gives birth to live pups, or the pups develop in the body without an egg.
The litter size, or how many eggs or pups are inside the mother at a time, depends on the type of shark.
The great white shark usually has about two pups in a litter but can have as many as 10. These pups start out as eggs, and hatch inside their mother’s belly. While inside, they eat un-hatched eggs and sometimes they even eat each other! When they’re born, the pups are about five feet long, and they immediately swim away from their mother to find something to eat.
The whale shark also develops eggs that hatch while they’re still inside the womb. A female whale shark can give birth to 300 pups in one litter, each one measuring about two feet long!
The Most Dangerous Sharks to Humans
The great white is the most dangerous shark when it comes to attacks on humans. Even though there are a lot of people who are terrified of great white sharks (the word for “fear of sharks” is “galeophobia,”) you’re much more likely to die from a dog attack or a bee sting than a great white shark attack. Sharks only attack about 75 people a year worldwide, and only about 10 percent of attack victims die. That’s because sharks don’t actually eat humans since we taste disgusting to them and our bones are too difficult for them to digest. Great whites often mistake swimmers for fish and surfers for seals, but once they take a bite, they realize their mistake and usually swim away.
The second most dangerous shark for humans is the tiger shark, which will eat just about anything. In fact, scientists have found tiger sharks with things like boat cushions and alarm clocks in their stomachs!
The third most dangerous shark is the bull shark, which can live in salt water and fresh water. Bull sharks have actually been found swimming in the Mississippi river!
The Biggest Danger to Sharks
What do you suppose the most dangerous predator is for sharks? Orca whales, maybe? Or bigger, stronger sharks? Those are certainly dangerous predators for sharks, but the biggest danger they face is… humans!
That’s right. Scientists recently estimated that humans kill around 100 MILLION sharks every single year. That adds up to 273,972 sharks killed every single day, or 11,415 killed every hour. And the scientists point out that those estimates might be low, and the actual number may be closer to 275 million.
Some sharks are killed for their fins, which is the main ingredient in shark fin soup,/a>, a Chinese delicacy. Others are killed by sportsmen and people who want to make money selling the jaws as souvenirs. But humans don’t always kill sharks on purpose. Many sharks die because humans have destroyed their habitats by drilling for oil or polluting the fragile marine environment. A lot of sharks also die after getting trapped in fishing nets or the nets that are set up near beaches to keep them away from swimmers.
We really should take better care of sharks and their environment, don’t you think? If sharks were to disappear, the marine ecosystem might not survive, because sharks are extremely important for keeping fish populations under control.