How does a dolphin echolocate?
Delphinus delphis, also known as the "saddleback" or
"common dolphins." Photo by William A. Watkins.
Courtesy of Woods Hole Oceanographic Institution.

How does a dolphin echolocate?

Dolphins and other toothed whales locate food and other objects in the ocean through echolocation. In echolocating, they produce short broad-spectrum burst-pulses that sound to us like "clicks." These "clicks" are reflected from objects of interest to the whale and provide information to the whale on food sources.

Marine mammals must channel these clicks to accurately locate object. This channelling is aided by fat deposits located in the brain case of toothed whales. In sperm whales, these can weigh many tons. This fat deposit in other toothed whales, called the melon, is smaller. Another large fat deposit, located in the lower jaw, is strategically placed behind an area of the jaw where the bone is very thin. This deposit is similar in composition and extends up to the middle ear region.

When the animal creates the "clicking" echolocation sounds, they are focused in a directional beam by the melon. The echos that are reflected from food sources are received at the "acoustic window" area in the lower jaw. From there, the acoustic information is transmitted to the middle ear, and ultimately to the brain for interpretation.

And then, it's time to eat!

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