A Brief Look At Sharks Senses
A sharks senses have evolved with sharks to become an effective and efficient means of survival. It is interesting to note that because sharks have no other predator but man, they are not equipped with some of the defensive mechanisms of other sea creatures.
A sharks senses work in unison to make it an efficient predator that can sense injured animals and fish from several miles away. Experiments have been done on some shark’s to get an idea of how the senses of a shark work together with interesting results. When a shark’s nose is stopped up it has significant difficulty hunting, even though the sense of smell is not the primary sense. The entire body of a shark plays an important role in the effectiveness of the senses and it’s ability to hunt and survive.
Many sharks have light sensitivity that is ten times more sensitive than humans. They can see objects from 70-100 feet away. Depending on whether the shark is a bottom feeder or surface feeder, they may have extremely good eyesight or very poor eyesight. Researchers have found that Lemon sharks can detect colors and that they prefer bright shiny colors.
Two highly developed senses are hearing and smell. In tests on sharks in captivity, one drop of blood could be detected in 2,000 gallons of water. In the ocean sharks can smell blood from many miles. In addition, many sharks are attracted to the scent of chemicals in the gut and can be found at sewage outfalls. Another interesting feature of a sharks sense of smell is their ability to smell directionally. When a smell enters their nostrils, the scent enters the nostril first that is in the direction of the scent. Their hearing is received, unfiltered directly from the hole in their head to the inner ear. Sounds with a very low frequency are heard easily from as much a . 6 miles away.
Sharks have two senses that humans do not share. These senses give the shark an advantage as a predator and provide it with the ability to detect injured animals from a great distance. First, the head of the shark contains Ampullae of Lorenzine. These are small ampules that are electroreceptors. All animals, including humans emit an electromagnetic field. When injured, the electromagnetic field changes slightly. The receptors detect this change from several miles away and attracts the shark to the prey.
The Lateral Line is also unique to the shark. These tubes look a lot like an ear canal with tiny hairs along the length of each tube. They run along both sides of the shark and end in the brain. The Lateral Line is able to detect vibrations in the water from ten feet away and senses frequencies of 25-50Hz. If there is splashing or distress in the water, the shark can sense it with their Lateral Line.
When all of the sharks senses are combined they create a perfect method for a fish that spends most of its life hunting for prey that is hiding or moving in a vast ocean.
In her studies of sharks one aspect that has always fascinated Pam Golding is sharks senses.
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