In Alaska’s Cook Inlet, belugas swim in turbid water that resembles liquid mud. It’s impossible to see just a metre below the surface and yet belugas manage to hunt here. How do they spot their prey in this mud? Like most toothed whales, they use echolocation.
Toothed whales have the ability to emit sounds that reflect off objects and organisms around them. These sounds, which travel very quickly through the water, bounce around virtually everywhere. By retrieving the echoes of these sounds, the animals get enough information to see without having to rely on their eyes.
This type of biological sonar allows toothed whales to navigate and hunt in dark waters where visibility is quite poor. This tracking system is so accurate that dolphins in an aquarium can distinguish objects the size of a corn kernel 15 metres away!
Echolocation takes place in two stages: first, the animal emits sounds and then it analyzes them. The sounds originate in the whale’s head and are concentrated in the melon, the bulge on its forehead.
When the sound strikes an object, it returns to the animal through sound-conducting tissue in the lower jaw. From there, it travels to the inner ear (whales have no external ear!), where it completes its journey. The brain then processes the information.
Last updated: July 2019
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