New Delhi: Squid hair could help scientists better understand how human hearing works and how it fails. These tiny sensory cells found across a squid’s body work in a surprisingly similar way to the cells that allow humans to hear.
In a recent study published in Current Biology, researchers at the Case Western Reserve University in Ohio found that squids have hundreds of hair cells spread all over their body. Hair cells are sensory cells that respond to movement. In humans, these cells are found deep within the inner ear, inside a snail-shaped organ called the cochlea.
These findings could help researchers understand hearing loss because damage to these cells affects hearing. Unlike the hair cells in the human inner ear, which are difficult to access, squid hair cells are found on the creature’s body, making them easier to study.
“Often, when a child is born deaf or a hearing person loses their hearing, it is the hair bundle that has been damaged. So, studying the squid’s hair bundle holds promise for understanding how hearing loss occurs,” lead author Brian McDermott, associate professor at the Case Western Reserve School of Medicine, said in a statement.
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How hair detect sound
When sounds enter our ear the vibrations reach the cochlea where thousands of hair cells are nudged into movement. This mechanical movement is then converted into signals that travel through the nervous system to the brain which interprets them as sounds. The hair cells themselves are of different heights and respond to different frequencies.
What scientists have discovered now is that squids have similar hair cells which are arranged in lines across their body. In squids these cells are a part of the sensory system that helps them detect movement and vibrations in the water around them.
“Squid are cephalopods with a diverse population of hair cells on the surface of their bodies, which may yield insights not only into how these fascinating animals detect water movement to survive, but also into how hearing and deafness occur in humans,” McDermott added.
To find these cells, researchers used a light-sheet microscopy, a method that shines a laser through a squid to then build a 3D image of the creature’s structure. Along with discovering the hair cells, researchers also found that, like in humans, squids too had hair cells of differing lengths which respond differently to movements of water.
Other sea creatures such as fish and octopuses too have such hair on their bodies. Much of their survival depends on being able to sense different frequencies of water movement. Researchers believe that their skin acts like the human ear. These similarities are likely to give scientists a new way of studying and understanding one of the most delicate parts of our auditory system.