shark
- Sharks are attracted to anything below 40Hz
- Some sharks have Nictolinid membranes as eyelids which closes when it bites its prey
- Their jaws can extend forward
- Sharks lose more than 6000 teeth a year and can be replaced within 24 hours
- Their bites have exerts a pressure of 42 000 pounds per square inch just like humans
- The wierdest thing found in a shark was a medival armour
- The Nurse shark has the suction power of 12 vacuum cleaners for sucking out shell fishes
- 1/4 million gallons of water passes through the gills of a whale shark in an hour
- When sharks are overturned, their sensors are over stimulated and they enter tonic immobility
- Goblin sharks have beak noses
- Epolet sharks are small and walk on the ocean floor
- Bull sharks can survive extremely well in fresh water
- Nurse sharks mate by biting the fins and overturning the mates. This however cuts of the oxygen supply of a shark and courtship has to be done quickly
- Females can excrete the male sperms if they are already fullgu
- Sharks have 2 sex organs (males)
- 30% of eggs are egg sacks on the ocean floors which are leathery
- Sharks have enlarged livers filled with 18 gallons of an oil lighter than water to give the shark bouyancy. Some of them simply gulp air to stay on the upper levels of the sea
- Stingrays are a branch off from sharks
- Dermatenticles are the teeth on the sharks body which gives it streamline
- Hammerheads seem to follow lava flows and happen to congregate around volcanic peaks. They seem to be following the magnetic field emmited by the lava streams
- A shark is the only fish that can blink with both eyes.(sometimes before they take a bite out of something)
- For most shark species, females grow around 25% larger than males
- The spined pygmy shark has dense photophores covering its ventral surface but little or none on its sides or top of the body. This bioluminescent pattern has been described as “photophore countershading”. On a moonlit night, fish swimming through the water would normally produce a shadow that predators would see. The glowing underside of the spined pygmy shark reduces or eliminates this shadow, making it less conspicuous to predators
- Sharks must constantly swim in order to breathe. They cannot forcibly create a vacum to suck water into their mouth and pass it through their gills like other fish, so must resort to ‘netting’ the water with their ever moving mouth. Sharks also have a low blood pressure. The walls of the pericardium (the membranous sacs that enclose the heart) are rigid, creating a suction within the pericardium to maintain the flow of blood. To circulate blood throughout their bodies, many sharks must swim continuously
- The eye has a layer of reflecting plates called tapetum lucidum behind the retina. These plates act as mirrors to reflect light back through the retina a second time. The tapetum lucidum of a shark is twice as effective as that of a cat. In bright light, pigments temporarily cover and block the tapetum to prevent eye damage from intense light
- Sharks have an acute sense of smell. They are well-known for their ability to detect minute quantities of substances such as blood in the water. Sharks can detect a concentration as low as one part per billion of some chemicals, such as certain amino acids. A shark’s sense of smell functions up to hundreds of meters away from a source
- If a shark eats something terribly upsetting, some species can force their stomach out through their mouth and into the water to empty it out
- Sharks have tongues. However, they are called ‘basihyal’ and are short stout cartilagenous points in their mouth.
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