The Awesome Shark: Facts and Myths

There are an estimated 350 known species of sharks, with a great range of size and shape.
The largest is the whale shark which grows up to 12 meters (40 feet) long, and the smallest is the dwarf shark that matures at a length of 150 millimeters (6inches).

Contrary to popular belief, most sharks are harmless to humans. Of all shark species, about 80% grow to less than 1.6 meters (5 feet) and are unable to hurt people or rarely encounter people.

Sharks live in all parts of the oceans, from shallow to deep water, and from the tropics to the Polar Regions.

Sharks have remarkable senses

In addition to touch, taste and a keen sense of smell, sharks possess excellent vision at close range and two unique senses - The Lateralis System (to detect vibration) and the Ampullae of Lorenzini (Sensory organ to detect very weak electric fields).
Since everything living produces an electrical field, the sharks can sense that something alive is in the water before it even sees or smells it.

A shark may grow and use over 20,000 teeth in its lifetime. Sharks never run out of teeth.  Behind the first set in the front are many rows developing. As the next row moves forward a full set replaces the damaged, older set.

Sharks are some of the oldest animals on the planet.  They have been around much longer than man or any other mammal – probably as much as 400 million years – and they haven't changed very much in at least the last 30 million years.

Sharks are ten times more sensitive to light then humans. Sharks don’t communicate with sound. They don’t even have organs for sound production. Sharks have no bones, they only have cartilage. Sharks eat 2% of their body weight when they eat. That is less then what humans eat.

Did you know that sharks can’t swim backwards? Just another reason why they get stuck in drift nets.

Because most sharks don’t mature until they are six or seven years old, and then will only have a small number of pups a year, population sizes of sharks don’t recover easily once they have been decimated, unlike other schooling fish such as tuna, which hatch thousands of eggs every year.

Sharks are very important to maintaining the balance of nature in the sea. 
They are in charge of eating diseased and dead fish and other sea creatures to keep the strongest living and reproducing. Without sharks, ecosystems could be completely destroyed.

From Sharktrust.org

Sharks - Myth vs. Fact

Myth : Sharks will eat just about any bait.
Fact : While some sharks will eat just about any chunk of fish or meat used for bait, most sharks are a lot more finicky, and prefer a lively fish. Even more so, sharks that are fished for as game fish on the flats will only bite a bait that naturally occurs in that area.

Myth : Sharks eat all the time.
Fact : Sharks eat periodically depending upon their metabolism and the availability of food in the area. Some sharks, like the lemon shark eat less than two percent of their body weight per day.

Myth : Sharks attack more at night.
Fact : Sharks may feed more at night, but very few attacks occur at night. Of course this might be due to a tiny percentage of people actually swimming or diving at night.

Myth : Sharks have to swim constantly to survive.
Fact : Some do, but many others can respire by pumping water over their gills through opening and closing their mouths while at rest on the bottom. Just don't swim up to a motionless shark on the bottom, a startled shark can be quite dangerous.

Myth : Sharks are trash fish of very little value.
Fact : Sharks are a critical part of marine ecosystems, especially in keeping the food chain in order. Without sharks, various species of fish would be very susceptible to disease and over population.

Myth : Sharks have poor vision and rely on other senses.
Fact : Sharks' eyes, which are equipped to distinguish colors, employ a lens up to seven times as powerful as a human's, and some shark species can detect a light that is as much as ten times dimmer than the dimmest light the average person can see.

Myth : Most species of sharks are dangerous to people.
Fact : According to the International Shark Attack Files, of shark attacks recorded since the year 1580, only 10 of 400 species were involved in unprovoked fatal attacks. Bull, Tiger, white Sharks account for almost all attacks--and many of those attacks are assumed to be accidental.

Myth : The Great white is a common shark found off beaches visited by humans.
Fact : Great whites are relatively uncommon large predators that prefer cooler waters. In some parts of their range, great whites are close to being endangered.

Myth : Whale sharks, the largest species of sharks, are voracious predators.
Fact : Whale sharks, which are the largest fish that ever lived, are plankton feeders like the great whales, thus the name.

Myth : Sharks are very hard to kill.
Fact : The stress of being captured easily weakens a shark. Often sharks are killed by hook-and-line fishermen and commercial netters.

Myth : Sharks have tiny brains and are incapable of learning.
Fact : Sharks' relatively large and complex brains are comparable in size to those of supposedly more advanced animals like mammals and birds. Sharks also can be trained.

Myth : Most sharks cruise at high speed when they swim.
Fact : Although some sharks can swim at bursts up to 25 mph, most sharks swim very slowly at cruising speeds around 5mph.

Myth : Sharks are not found in freshwater.
Fact : A specialized osmoregulatory system enables the quite popular bull shark to handle dramatic changes in salinity -- from the fresh water of lakes and rivers to the highly salty waters of the ocean.

Myth : Sharks are not discriminating eaters and scavenge the sea.
Fact : While this belief about shark eating habits is true of some species, it is not universally true. A tiger shark may gulp down anything it encounters, including trash, but most species of sharks prefer to eat fish, crustaceans and mollusks.

Myth : Sharks must roll over on their sides to bite.
Fact : Sharks can attack from whatever direction they please. They have a unique jaw design that allows them to protrude their jaw beyond their snouts, so they can even latch on to something directly in front of them.

Myth : Sharks have no enemies.
Fact : The greatest enemy of sharks is man. He kills and hacks off the fins of 30 to 100 million sharks each year. That is, in three to five years fishers kill the equivalent of the entire population of the U.S. Humans are not natural predators of sharks, as we are terrestrial hunters and didn't really fish for sharks until we became civilized. Now we cut off fins and throw the living creature back to die on the bottom of the sea.

Myth : Shark cartilage pills can prevent or even cure cancer.
Fact : While sharks and their close relatives have demonstrated a strong resistance to cancer, they are not entirely immune to it. There is no evidence that consuming shark cartilage will help prevent or cure this disease in humans. Dispelling this myth is crucial to help slow the demand for sharks by medical hoaxsters who are needlessly aiding in the decline of shark populations.

Myth : There are too many sharks in the sea.
Fact : Anybody who does much fishing in the sea can attest that shark populations often seem to be on the decline. Over-fishing, water temperature changes and environmental pollution are all thought to be responsible for depleted shark populations.

Myth : Sharks have been around forever and always will be.
Fact : Wishful thinking. Without human protection, conservation and ongoing advances in science, many species may become extinct. Luckily, many sportsmen these days are realizing this, and the trend to treat sharks as a nuisance is declining.