Sharks. Sharks. Great white shark breaching. Sharks are amazing fish that have been around since long before the dinosaurs existed. They live in waters all over the world, in every ocean, and even in some rivers and lakes.
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Sharks are amazing fish that have been around since long before the dinosaurs existed. • They live in waters all over the world, in every ocean, and even in some rivers and lakes. • Unlike bony fish, sharks have no bones; their skeleton is made of cartilage, which is a tough, fibrous substance, not nearly as hard as bone. Sharks also have no swim bladder (like bony fish do).
Sharks may have up to 3,000 teeth at one time. • The teeth are arranged in rows; when one tooth is damaged or lost, it is replaced by another. • Most sharks have about 5 rows of teeth at any time. The front set is the largest and does most of the work • Most sharks do not chew their food, but gulp it down whole it in large pieces.
Ampullae of Lorenzini • The ampullae of lorenzini are small vesicles and pores that are part of the skin’s sensory network system. • These pores detect weak magnetic fields produced by other fish and allow it to locate prey that are buried in the sand.
Do Sharks Sleep? • Fish don't sleep in the same way that we do, but they have active and inactive periods. • Some sharks (like the nurse shark) have been observed resting motionless on the sea floor, but others have to keep moving in order to breathe.
Fun Facts: • More people are killed by bee stings than by shark attacks. • More than 90% of people who are attacked by sharks survive the attack. • Sharks' bodies are heavier than the sea, so if they stop moving they sink. If they want to stay afloat, they must keep moving!
No Cancer? • It was thought that sharks never get cancer! It was the craze to take shark cartilage (powdered) because it had cancer fighting properties. • However, in 2000, researchers at John’s Hopkins discovered several types of tumors and cancers in various sharks. http://www.canoe.ca/Health0004/06_cancer.html http://www.seacure.com.au/Default.asp?c=5586
Shark skin • Shark skin is covered with tiny tooth-like structures called denticles that protect them from abrasion, parasites, and helps them to swim efficiently by reducing drag
More Shark Facts • The biggest meat-eating shark is the Great white shark (Carcharodon carcharias) which grows to be up to 21 feet (6.4 m) long. Great whites up to 37 feet (11.3 m) long have been reported, but not verified.
MOST COMMON SHARK • The piked dogfish shark (Squalus acanthias) is very abundant, especially in the North Atlantic Ocean. It is a small shark, about 63 inches (1.6 m) long.
DEEPEST DIVER • The Portuguese shark dives down over 9,000 feet (2750 m). This is over 1.5 miles
Biggest shark ever! • The largest shark known was the Megalodon (Carcharodon or Carcharocles megalodon); it is now extinct. It was an ancient, meat-eating shark that lived between 25 million and 1.6 million years ago. It was up to 40 feet (12 m) long and its teeth were each the size of a person's hand!
Smallest Shark • The smallest sharks are: Dwarf Lanternfish (Etmopterus perryi), which is about 7 1/2 to 8 inches (19 - 20 cm) long for fully-grown females and 6 to 7 inches (16 - 17.5 cm) long for adult males
Fastest • The fastest swimming sharks are the mako sharks and blue sharks, which can even leap out of the water. They are also probably the fastest fish. Estimates of their speed varies; some say that they can swim at about 60 miles per hour (97 kph), while more conservative estimates are about 22 mph
Longest Tail • Thresher sharks -the upper lobe of their tails are about the same length as their bodies.
STRONGEST SHARK BITE • The strongest shark bite belongs to the dusky shark (Carcharhinus obscurus); its jaws have been measured to exert 132 pounds (60 kg) of force per tooth!
Largest Litter One Blue Shark was found with 135 pups in her uterus.
