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 | What are Sharks?
 | Sharks are fish that have been around since the dinosaurs.
 | Males are called "Bulls" |
| Females are called "Cows" |
| Baby Sharks are called "Pups" |
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| Why are people afraid of Sharks?
| Many Sharks are "carnivores" which means they eat meat. They have rows of
razor-like teeth and special senses that help them hunt for their food. Most of the time
they eat smaller fish, but sometimes they will eat mammals, such as sea lions, dolphins
and very rarely humans. Most of the attacks on humans are from a "test bite" to
see if it is a food that it likes. People are not one of the Shark's preferred foods. The
shark will "test bite" something if it looks like food. People who are lying on
a small raft or on a surfboard may look like a sea lion from under water. |
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| Other shark facts
| Sharks have five to seven gill slits. Many sharks must keep moving in
order to breathe that is, in order to keep water moving past their gill slits but this is
not true of all species. Nurse sharks, for example, can lie still and fan their gills to
bring oxygen-rich water across the slits. Because they lack a swim bladder, all sharks
must swim in order to avoid sinking toward the ocean floor. |
| The shark has senses specially adapted for the animal's life underwater.
Smell is a shark's most acute sense. Approximately 70 percent of the shark's brain is used
for olfactory (smelling) functions. Experiments have shown that sharks can detect
prey solely by smell, and the hungrier the shark, the less stimulant needed to elicit a
reaction. |
| Sharks are sensitive to light and can detect certain objects even in
murky water. Some have a tapetum lucidum, a mirror like layer under the retina of
the eye that reflects incoming light and increases the amount of light available to the
eye. (Cats and other animals whose eyes "glow in the dark" also have this
feature.) |
| Sharks do have ears, but the role of hearing in the shark's location of
prey is not well understood. A shark can detect sound waves and disturbances in the water
with its lateral line, or lateralis, system. This is a series of thin canals, filled with
water, that runs along the animal's side. The canals are attached to nerves that send
signals to the shark's brain. |
| Sharks can also sense electric and magnetic fields. Sensory pores located
on the shark's head can detect a prey's bioelectric field even if the prey is buried in
sand. A shark can also detect the Earth's magnetic field. Open-ocean sharks may use this
information to navigate and orient themselves. |
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