Fish are cold-blooded animals that live in water. Most fish have scales on their bodies, use gills to breathe and have fins instead of arms or legs or fingers or toes. And they range enormously in shape and size – from tiny seahorses to huge whale sharks!
But have you ever wondered if and how fish can hear? We have! So, let’s find out more about fish and how they sense the watery world around them…
You might remember from my post about what’s that noise? that sound is made by the vibration of molecules. Often when we think about sound, we think about noises travelling through the air. And us humans hear them when they make our eardrums vibrate, sending messages to our brains.
But the sorts of vibrations that make the sounds we hear can also travel through liquids or solids. And fish are able to sense vibrations in the water using special parts inside their bodies. Different types of fish have different ways to sense these vibrations, these include:
- special hairs called cilia (pronounced ‘sillier’) that send signals to the brain about the vibrations they sense
- swim bladder (a gas-filled sack) inside the body, which helps fish to float at the right depth of water
- special bones called ‘ossicles’ and ‘otoliths’ inside their heads that sense movement
Now, whilst fish don’t talk to each other like we do, being able to ‘hear’ vibrations in the water is an important skill because it allows them to learn about and make sense of the environment in which they live. For example, it helps them to find food and to escape from danger (like bigger fish that want to eat them).