Visibility underwater is often limited, especially when the water is murky. That’s why aquatic animals need to “see” in a different way. While fish can perceive vibrations in the water, dolphins have specialized in navigating and detecting prey through echolocation.
This system relies on producing a sound that, originating from the animal and traveling at high speed (water conducts sound 4 to 5 times faster than air), bounces off the object to be detected and returns to the dolphin, providing information about that object.
Dolphins produce sound in a complex structure located beneath their blowhole (the opening through which they breathe), and the sound passes through the dolphin’s forehead via a fatty organ known as the “melon,” which projects the sound forward.
Upon returning, the sound is captured by the teeth of the lower jaw, which absorb the sound vibrations and transfer them to the mandible bone, from where they travel to the middle ear through a channel of fatty tissue.
These animals can locate, through sound, objects the size of a tennis ball up to 120 meters away and detect objects at close range the size of a shotgun pellet.
This incredible ability is due to the dolphin’s brain emitting around 700 sound signals per second, while the human brain has an analytical capacity of only 20 to 30 signals per second.
That’s why when diving with dolphins, the human ear picks up a series of clicks and chirps that together sound like a rusty hinge.
However, the dolphin can distinguish the subtle variations in the signal, obtaining vital information for the animal.
A dolphin can differentiate between a copper plate and an aluminum plate, even if they are painted the same color, and can distinguish between a hollow tube and a solid one.
These data on the consistency of objects are crucial when it comes to biting into them. Dolphins can also use these sounds to stun or scare their prey, causing a shoal to remain compact, facilitating their actions. It is believed that this sound is also the basis of a sophisticated communication system.
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