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Dolphins have an unique tool that is used for hunting and also communication. This tool is known as echolocation. Echolocation is better known as dolphin sonar. By listening to the echoes of the sound they produce, dolphins can locate objects and fish with remarkable success. This is termed as the dolphin’s x-ray vision. A dolphin is able to create an acoustical picture of its environment using the pulses of ultrasonic sound which bounce off objects.
Many Navy experiments have involved dolphins. There have been experiments with captive bottlenose dolphins in which suction cups were placed over the dolphin’s eyes, the dolphin was still able to echolocate to make its way to the target. The navy uses hydrophones (underwater amplifying devices) and they picked up that echolocation, which sounded like a bunch of clicks or squeaking sounds. These clicks are beyond the realm of human hearing. In experiments dolphins were able pick up minute objects with their echolocation with remarkable accuracy.
How do Dolphins do this? The answer to that question has a lot of different theories and ideas. Scientists today still ponder the correct answer to that question. Some believe that the dolphin’s echolocation key is held in its lower jaw. In experiments where a soundproof hood was placed over the jaw, dolphins had a tough time echolocating. Other scientists claim that the ear canals, even though drastically reduced in dolphins, hold the key to echolocation.
By sending out clicks, an echolocating dolphin can learn about its surroundings by measuring how long echoes take to come back. A dolphin can differentiate between the densities of objects. What is amazing is that they can tell the difference between different species of fish. Talk about being able to pick your dinner.
Dolphins appear to use echolocation as a primary tool in hunting. Not only can echolocation be used in the detection and tracking of prey, researchers speculate that the echolocation sound beam can stun a fish. It is thought that dolphins stun large schools of fish with the sound beams and then make the attack.
It is not certain if dolphins echolocate constantly. It is perhaps thought that once they echolocate and learn their way around, they navigate based on past echolocation. This is probably true because dolphins increasingly get caught in fish nets. Echolocation beams are not without limitation. They are narrow and directed forward. A dolphin’s vision may pick up where its echolocating abilities have left off. One thing to consider is how dolphins are able to make these sounds since they lack vocal cords. The dolphin’s nose is located on top of its head and within it houses a chamber in which sound is produced. The sound is conducted out of the melon. The melon is the located at the top of the dolphin’s head. The melon focuses the sound so that they are emitted in a narrow beam.
Echolocation is still a mystery. It evolved to make dolphins adept at hunting and communicating. It provides dolphins with an abstract sense of sight within their watery world. About a dozen species of dolphins and whales possess nothing similar to the echolocation of dolphins, but it is not sure if they used echoes from low frequency sounds. Bats also have this ability to echolocate and is thought that they use it primarily as a navigation tool.
Echolocation is still a mystery that will take several experiments to further unravel. Think of what it would be like to possess this somewhat mystical ability. We would never have to use our eyesight and we would still know what was up ahead.
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