by Linda Rahm, art by Brian Biggs
Dolphins listen for an echo to tell them the location of things in their watery world. And not just location. They can also sense size, shape, and texture. With echolocation, a dolphin can know that there is a three-inch steel ball 100 yards away, or that a single teaspoon of water is being dropped into its tank.
Here's how it works. From a place on the dolphin's head called the “melon,” it sends out rapid, ultrasonic clicking sounds—up to 700 clicks per second—in a focused beam of sound that echoes back when it encounters an object. Like a bat or a submarine, the dolphin is using a form of sonar, or “SOund NAvigation and Ranging.”
Echolocation is so powerful that it lets dolphins “see through” things. They can detect a “mystery object” inside a box underwater and later match it with an object they see above water.
Echolocation helps dolphins find prey hiding under rocks. Some researchers think that the high-speed sound waves may even stun the fish!
- A system or device like radar that uses reflected sound waves for detecting and locating underwater objects.
- A sound frequency that cannot be heard by the human ear.
- What is echolocation? Why do dolphins use echolocation?
[anno: Echolocation is a series of clicks sent out by a dolphin from an area of its head called the “melon.” The sounds bounce off an object. The dolphin can tell an object's size, shape, texture, and distance by using echolocation.]
- Do you think echolocation would work as well in the air? Why or why not?
[anno: Echolocation would not work as well in the air because sound travels faster in the water than in the air.]