Can crabs hear?

Yes, crabs can hear, but not like we do. Crabs and all other crustaceans lack ears like ours, because they are invertebrates and so do not have the bones and cartilage that would be needed. So you cannot point to one part of a crab and say, ‘That is an ear.’ Also, because crabs often live under the water they have a different need for ‘hearing’ than we do. But there are some similarities.


Illustration: Jo Taylor / Source: Museum Victoria

When we hear a noise we are essentially listening to sound waves, which are changes in air pressure. Crustaceans do a similar thing, but they ‘hear’ changes in water pressure around them. Instead of ears they have tiny (microscopic) hairs all over their hard shell, and particularly on their antennae. There are several different types of hairs, each connected to a nerve connected to the nervous system.

One type of hair responds to physical stimuli such as water movement, vibration or touch. These hairs are called mechanoreceptors and they respond to a stimulus by sending a message to the nervous system. Some of the mechanoreceptors respond particularly to vibration or changes in water pressure – these are the ‘hearing hairs’. A different type of hair is sensitive to chemicals in the water, and these are the ‘smelling hairs’.

But even with these hearing hairs, crustaceans hear differently from humans. If you play soft music to a crab, for example, the crab might or might not change its behaviour. But if you jumped up and down near a crab it would be much more likely to respond – usually by trying to escape from the source of the vibration. So crustaceans are often more responsive to vibration rather than noise – and that is how they hear.

Comments (5)

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nick 8 April, 2010 05:22
thnx very much this helped alot
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laurent 24 May, 2010 10:45
thnx this information is helping me with my information report
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Fran 16 February, 2011 04:41
Really Helpful for my Science hw :)
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me 22 March, 2011 09:41
Yeah umm that helped :D
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Susan 5 January, 2012 14:45
This info was very useful. We just visited the Aquarium in Gatlinburg, TN and they play LOUD music in the crab tank to get them to move their antennas to the beat of the music. This was pure torture for those enclosed sea creatures that have to lived with this all their life just to get tourists to "laugh". If you all visit there, tell those stupid Hillbillys they are wrong to torment animals ! !
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