Belugas are small white whales known as the "canaries of the sea" for the wide range of vocal sounds they make. They produce an impressive collection of clicks, chirrups, squeaks, whistles and bleats.
As the BBC points out, belugas make all these sounds despite having no vocal cords. Instead they "speak" through nasal sacs located around their blowhole.
These Arctic whales are also known for the distinctive rounded structure on the top of their forehead. Called a "melon," the bulbous structure is just in front of the whale's blowhole.
While these whales are talking through their noses, they're able to direct those sounds using their melons. Belugas wiggle their melons to focus sounds in specific directions. During whale vocalizations, researchers have watched melons changed shape, reports Whale and Dolphin Conservation.
The squishy blob is also believed to be key in helping with ecolocation "clicks," the echoing calls that some animals use to help find and identify objects. According to the Georgia Aquarium, the melon focuses and projects echolocation signals through the water.
Because the melon is made of lipids or fatty tissue, it's flexible and can change shape. That allows the beluga to make different facial expressions, reports the World Wildlife Fund.
All toothed whales (not baleen whales) have melons, but only the beluga's melon is squishy with the ability to change shapes.