All sharks do have a nictitating membrane which is a third eye.
And this 3rd eyelid that the sharks have cover the sharks eye while the shark feeds on prey to help protect the sharks eye.
Colors that scare sharks are black and blue while bright colors such as yellow, white, orange, red etc can attract sharks.
Sharks can hear your heartbeat as far as 328 ft away.
Sharks are equipped with sensory organs which allow the sharks to sense electric current from heartbeats of prey and humans within a 328 ft radius.
The things that sharks fear the most are dolphins and killer whales also known as orcas.
Dolphins and killer whales can actually easily harm and kill a shark so that is why sharks fear them the most.
The Pardachirus marmoratus fish (finless sole, Red Sea Moses sole) repels sharks through its secretions.
Things that repels sharks are magnets and Pardachirus marmoratus fish (finless sole, Red Sea Moses sole) repels sharks through its secretions.
Magnets repel sharks because the magnets interfere with the sharks ability to sense electrical fields.
The smell that sharks hate are the smell of death and the smell of rotting shark carcasses.
The 'smell of death' has been proven to be a tremendous deterrent in sharks, and, in particular, in Great White sharks.
The amount of shark attacks per year is around 137 of which 73 of those shark attacks per year are unprovoked.
Sharks attacks are actually pretty rare although they do happen.
The type of shark that has attacked the most people is the Great White Shark also known as the white shark.
The shark that has killed the most humans is the Great White Shark.
The Great White Shark has killed at least 52 humans and have attacked 333 people without being provoked.
Shark attacks do happen in shallow water and in fact most shark attacks on swimmers happen when swimmers are swimming in shallow water.
There are on average of 19 shark attacks per year and one fatal shark attack every 2 years.
The country that has the most shark attacks is the United States.
The places with the most shark attacks are.
United States. United States (All) California. Florida. Hawaii. North Carolina. South Carolina. Texas.
Bahamas & Antilles.
A shark's liver is so big to be able to compensate for the loss of lift that is caused by the shark having a bulkier body and for the relatively smaller fins.
The sharks liver contains light weight oils and also hydrocarbons which gives the larger sharks the increased buoyancy the shark needs.
Some sharks can breathe if they stop swimming by passing water through their respiratory system by using a pumping motion of the sharks pharynyx.
Doing this allows the shark to rest on the sea floor while still being able to breathe.
Other types of sharks must swim constantly to be able to breathe or they will die.
Sharks such as the nurse shark have spiracles that force water across their gills allowing for stationary rest.
Sharks do not sleep like humans do, but instead have active and restful periods.
Sharks sleep during the day and become active during the night.
The ocean that has the most sharks is the Atlantic Ocean.
The Atlantic Ocean is the home to most shark species although because of the high number of shark attacks the Indian Oceans and Pacific Ocean also have sharks in large numbers.
Sharks sleep during the day and not at night because sharks are nocturnal and they are active during the night.
During the night sharks hunt and attack prey and scavenge for their food.
Sharks do not see humans as prey and they are rarely dangerous to humans.
Sharks rarely attack humans and they would rather eat marine mammals and fish instead of humans.
A shark usually attacks if they see you as a threat but not because they want to eat you.
Sharks don't go crazy when they smell human blood although sharks can and sometimes do go crazy when they smell fish blood or sea lion blood.
Sharks do not go after human blood as sharks are not actually attracted to human blood.
Sharks are more attracted to fish blood or sea lion blood than human blood.
Sharks can and do attack humans but it's not because they smell human blood.
The blood that sharks prefer is fish blood and not human blood.
Sharks don't really like period blood or human blood although sharks can sense and smell period blood and human blood and might come to investigate but they won't typically attack someone when they smell or sense the blood or period blood.
Some species of sharks will sleep as they swim and other sharks will lay stationary on the seafloor to sleep and some other types of sharks will snuggle up in groups or someplace out of sight where it's safe for them to sleep and get some rest which can be in a cave or in sand.
Sharks do poop and the shark's poop comes out via the cloaca.
Sharks do also pee and they pee and urinate continuously.
When sharks pee the sharks urine is actually absorbed by the sharks flesh, where the urea is used to keep the sharks scale-like dermal denticles nice and moist.
The rest of the sharks urine is simply expelled back into the water through their 'skin'.
Sharks mate through use of the male sharks claspers that have extensions of their pelvic fins that release sperm into the female shark.
All male sharks have what are called claspers which are extensions of the sharks pelvic fins that are used to transfer sperm into the female shark.
Once inserted, the male expels sperm into the female along with seawater, and the eggs are fertilized inside the female's body.
Some sharks are egg-laying, while others are live-bearing.
Some sharks can live 300 years and even some sharks such as the Greenland Shark can live 400 to 500 years.
Some sharks can live up to 500 years.
The Greenland Shark lives on average of 300 to 400 years although in some cases the Greenland Shark can live up to 500 years.
The Greenland Shark is the kind of shark that lives the longest with an average lifespan of around 400 years.
The Greenland shark, also known as the gurry shark, grey shark, or by the Kalaallisut name eqalussuaq, is a large shark of the family Somniosidae, closely related to the Pacific and southern sleeper sharks.
Sharks do die of old age just like other animals and humans.
Sharks age faster than humans but a shark can live for up to 30 years although around 30 years of age a shark is considered to be around 85 to 90 years old in human years.
Sharks live for between 20 to 30 years.
The lifespan of a shark is 20 to 30 years although some sharks may live a bit longer than 30 years.
The shark or sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head.
Modern sharks are classified within the clade Selachimorpha and are the sister group to the rays.
Despite their scary reputation, sharks rarely ever attack humans and would much rather feed on fish and marine mammals.
Sharks are opportunistic feeders, but most sharks primarily feed on smaller fish and invertebrates.
Some of the larger shark species prey on seals, sea lions, and other marine mammals.
Whale sharks are essentially bulletproof, with six-inch-thick skin.
Though it's not the thickest in the animal world (sperm whales have skin measuring more than a foot thick), but it's tough enough that it's made it extremely difficult for scientists to get a blood sample of the creature.