Sharks vary in size from tiny sharks to the biggest, which can be as large as 60 feet. The average female shark is 15-16 feet long, while males can reach 11-13 feet. Although this is bigger than a human, not all sharks will attack humans!
Sharks do not only have one row of teeth like most animals but have several, with the average being five. Sharks can have as many as 3,000 teeth at once! The teeth are designed to be disposable and are being replaced continuously as they are broken off or damaged. The teeth in the back rows just move forward.
Sharks are really built for speed and can achieve high speeds underwater. The fastest shark can swim about 30 times faster than the average human. Sharks swim so fast because their tails swing from side to side. This creates twice as many jets of water and makes swimming much more efficient.
A Shark’s Bite Force
Sharks have a massive bite force, with big sharks exerting a bite force of nearly 1.8 tonnes. This gives them one of the biggest bite forces of any living animal, 3 times more than a lion and more than 20 times more than a human.
Tiger Sharks Eat Anything
A tiger shark is a voracious predator that will literally eat anything. They will eat anything from other sharks, fish, and crustaceans, to rays, and seabirds. They are indiscriminate eaters who will also eat non-food items when they find it in the ocean.
The biggest shark that ever lived, weighed as much as 30 Great White sharks put together. It was a fearsome hunter, preying on the early whales and other sea creatures. It is thought that the reduction in the availability of prey pushed it to extinction three million years ago.
Worldwide there is an average of 72 unprovoked shark attacks yearly, of which an average of 4.3 was fatal. Sharks normally won’t attack humans and would rather eat fish and other sea creatures, but sometimes a human gets mistaken for a seal or sea lion.
When talking about sharks, people tend to concentrate on the massive ones, like Megalodon and the Great White shark. But there are quite a few species of shark that will fit in the palm of your hand and are quite harmless to humans.
A Shark’s Sense of Smell
Sharks have about the same sense of smell as other fish and can smell blood that is diluted between one part per 25 million and one part per 10 billion, making it about one drop of blood in a small swimming pool. Sharks are drawn to the smell of blood and will attack an injured animal or human.
Shark embryos, stuck inside the egg case, are very vulnerable to a variety of predators. As the egg case starts to open, predators can sense the baby inside through changing electric fields. The embryo can, however, also sense the danger approaching by the same means.
Fishes and underwater creatures need to achieve neutral buoyancy. They can do this in different ways. Most fishes have a swimbladder that is filled with different volumes of gas. Other fishes store fats and lipds that is less dense than water and others balance blubber and bone.
Sharks have long been considered the top predator in the ocean, but there are animals that make a feast of shark meat. These include large fishes like the grouper as well as other animals.
The Hexanchiformes are the most primitive sharks alive today. They are strange, prehistoric-looking sharks that spend most of their time in the deep waters of the oceans far below the surface.
Oldest Living Species of Shark
Sharks first appeared about 380 million years ago. The golden age of sharks was the Carboniferous Period when sharks dominated and evolved in lots of different forms. Some of the sharks from that period are still around today.
Sharks in Freshwater
Sharks have evolved in saltwater and are adapted for a life in saltwater. They must retain salt inside their bodies, otherwise, their cells would rupture and they would die. There are, however, a few species of sharks that can tolerate fresh water for a certain time period.
Because sharks have no swim bladder, their skeleton needs to be lighter to aid with buoyancy in the water. Sharks have therefore evolved to have a lighter skeleton than land animals and even other fishes.
Hammerhead sharks can be recognized by their unusually shaped head. The Hammerhead has electrical sensors in the head that allows it to scan for food quickly. The Hammerhead has 360-degree vision because its eyes are placed on the sides of the hammerhead.
Longest Living Sharks
Sharks have various lifespans, depending on the species. Some sharks do not live very long, like the Blue shark which only lives 15 to 16 years in the wild. Other shark species live incredibly long lives, and only mature at around 150 years of age!
Sharks have featured in a lot of movies over time. Who will forget the greatest shaw movie of all time, Jaws? But not all sharks are monsters like the shark in Jaws – there are also very likable characters, like the friendly shark in Finding Nemo!
Sharks in Religion
In some countries, sharks are considered sacred. They are revered as departed relatives that inhabited the body of a shark and will act as family guardians. They are also considered to give guidance to travelers at sea.