LIFE IS AN ECHO
Below the surface light vanishes, colours disappear and the deeper we go, the less we see. And as we go blind, a world of sounds opens up to us, a perfectly tuned concert of all frequencies and imaginable noises .
But what is sound?
Sound is a form of energy made by vibrations. If we speak, we create such vibrations - or so-called acoustic waves. And as words leave our mouth, we therefore cause movements in the air molecules surrounding us. These molecules will bump into the next molecules and so forth, causing them to vibrate as well and transmit our words until they're received by our conversation partner (or whoever is listening). The receiver's outer ears transmit these vibrations to the inner ear and only then our brain interprets the signal and we actual "hear" (and therewith understand) what has been said.
If you now look at an image of a whale or dolphin, you'll quickly realise they actually don't have an outer ear like us or other landbase mammals - yet, they're capable of hearing way more and better than us!
How do cetaceans hear then?
Cetaceans are divided into two groups - toothed whales and baleen whales.
Toothed whales can echolocate. Dolphins for example emit high-pitched chirps or clicks in a rapid burst. These sound pulses bounce off any possible object that's in the path or direction the pulses were emitted. By listening to the echoes that return to the sender (in this case the dolphins), the animals are able to map their surrounding, navigate it and even locate prey.
Over all, toothed whales are mostly using high-pitched sounds to communicate, pinpoint prey or get around.
Now that whales and dolphins don't have an external ear like us, they instead receive sound pulses (the acoustic waves) through fat bodies that are embedded in their lower jaw, which then transmit the sound waves into the inner ear. The animal's brain is now able to picture what is around and memorises the area and all that's going on within it.
But what about the baleen whales?
Keep following our news feed and find out in our next post!
- Sarah
