How do fish talk

Can Pisces Talk?

Contrary to the saying "mute as a fish" and the assumption of many people, the fascinating underwater inhabitants are anything but quiet. The underwater world is full of noises: fish not only have fine hearing, they also make sounds themselves in order to communicate, to deter or threaten one another. But they are adapted to the living conditions under water and - unlike us humans and many animal species - have no vocal cords and no larynx. So how do they make the noise underwater?

Since the acoustics below and above water are different, noises generated under water can often not be heard on the surface. The sounds of most fish are in a frequency range of around 400 to 800 Hertz - these are sound waves that are also audible to the human ear.

Predatory fish often also generate infrasound sounds - i.e. very low frequencies that are no longer perceptible to humans, or ultrasound - sounds above the human hearing threshold. Hydro-bioacoustics deals with topics like these. Using a hydrophone, an underwater microphone, marine biologists perceive the noises below the surface. The device converts the water-borne sound into an electrical voltage that corresponds to the sound pressure. The mysterious underwater world that seems so "calming" and "quiet" to us is anything but quiet ...

How do the "silent sea creatures" make sounds?

The speed at which sound waves propagate in water is even more than four times faster than in air. Noises are very good underwater and can be heard over great distances. Fish produce sounds in different ways: High frequencies are often caused by the rubbing of bones and teeth against each other. Low sound waves are usually generated with the help of the swim bladder. In the majority of bony fish, this is formed from a protuberance of the foregut and primarily serves to be able to swim without exertion. When you swim upward, gas is released into the swim bladder and it expands. The dead weight is adjusted to that of the water.

Catfish and other fish that live on the bottom do not have such a bubble. Only a few species of fish, like sharks, are an exception: They are not bottom organisms and yet do not have a swim bladder. They therefore constantly need energy in order to generate buoyancy through permanent swimming and not to sink into the depth. A swim bladder, on the other hand, balances the weight by filling with air. Many fish do this by swallowing air. Inhabitants living at great depths fill their swim bladders through veins that are connected to their gills. In addition to swimming, "sounding" is another function of this organ. The sounds are made by fish using the internal or external muscles of the swim bladder.

The language of the fish

The sea creatures make very different sounds in different situations. Piranhas, for example, use their swim bladder to make a drum sound. Angelfish knock when they feel provoked or when they fight rivals. As the name suggests, gurnards make a grunting noise when excited - for example, when you take them out of the water - and the gurnard growls when it feels threatened. Loaches emit a "cracking sound" when hunting. Cichlid females hum to chase away annoying males. Small vendace "rustle" when they eat food together in the choir.

Carp squeak when they eat, and the females also make a drumming sound to lure male perch to spawn for the purpose of reproduction. If perch have found something to eat, they emit a knocking noise. The pike bark to threaten other fish. The call of the Argus fish is a drumming, but as a warning and deterrent it emits grumbling tones. Frying pan catfish growl from rubbing pieces of bone together when frightened. The African knifefish grunts and barks with its mouth open in threat - how exactly this sound is produced is still unclear.

See, hear, smell and taste fish

The sea creatures can - like other animals - talk using spoken language. In addition to their ability to see, most fish also have good hearing and a pronounced sense of smell and taste. Sharks, for example, with the olfactory organ on the side of the snout, can still smell blood in a billion-fold dilution - and can smell their prey from a long way off.

Their hearing sensation also plays an important role on the hunt: the ears of the shark are on both sides of the skull. The predatory fish is particularly interested in low frequencies below 600 Hertz, such as those generated by grunting seals, on their prey campaign. It reacts particularly sensitively to sounds below 100 Hertz, which suggest injured, weak and sick animals and would therefore be easy prey for the shark. Sharks hear low-frequency tones that the human ear can no longer hear. The fine taste buds of the fish are in the palate area. If they find their food "inedible", they sometimes just spit it out again. After a "test bite" they mostly return to the prey, which has been weakened by the loss of blood, in order to then devour it.