A Shark's Instinct
How smart are sharks?
It is hard to know if sharks act as they do because of intelligence or instinct. Many types of sharks have large brains. Often a large brain relative to total size means an ability to act in complex ways. Sharks can learn at the same rate as birds and rats. They can be taught to behave in certain ways when rewarded.
How do sharks detect prey?
Sharks detect prey by using most of their six senses. Their "extra" sixth sense is electro reception. Electro reception allows sharks to pick up small electrical signals that all living animals give off. The electrical signals guide the sharks to the prey. They have two senses of touch. One is for feeling if something is hot or cold. With the other sense of touch, sharks can sense vibrations from far away. The other senses that sharks have are hearing, smell, sight, and taste. The sharks usually use their sense of hearing to find prey. Sound travels a lot faster under water then it does in the air. Sharks can hear fish from about 3,000 feet away! Sharks also have a keen sense of smell. Half of a shark's brain is for smell. The shark's sense of smell increases as it gets hungrier. They can sense one tiny drop of blood in a huge tank of water! The ocean is cloudy and dark, but a shark's eyes are adapted to this. There is a mirror type surface in the back of its eyes which helps it see in the dim light. This makes a shark's eyes appear to glow.
What is a feeding frenzy?
A feeding frenzy occurs when a group of sharks comes together and eats anything it finds. The sharks are very vicious. The sharks keep up the slaughter even when they are hurt. Biologists don't really know why feeding frenzies happen, but they think it happens when the sharks' brains get overloaded by too much stimuli in the water. Stimuli can include prey, blood or irregular movements like those of a struggling fish.