Science of Hearing IV ( Hearing in Vertebrates)

Hearing in Reptiles and Amphibians

How do snakes hear?

Reptiles are the vertebrates living in borrows, or on the trees. Snakes are reptiles living in borrow. Snakes do not have ears outside the head. They do not have ear openings or eardrums. But they have the inner ear, inside the head. Vibrations caused by a person or animal walking by the side of the snake will pass from earth to its body. Snakes can feel vibrations from the ground. The vibrations pass through the skin and muscles of the snake to a bone connected to its inner ear. The brain recognises the sound heard by the inner ear.

Snakes can also hear noises or vibrations that travel through the air. Snakes do not have eardrums. Their skins, muscles, and bones carry the sound waves to the inner ears. In this way, snakes can hear sound carried by the air.

How do frogs hear?

Amphibians live both on land and in water. Amphibians hear very well. They can even hear the sounds which humans cannot. The ears of the frog are  located on the sides of the head. The ears are in the shape of small circles covered with membrane. This membrane is the eardrum. Sound waves spreading in air or in water cause it to vibrate; the membrane, in turn, transmits the signal through the auditory ossicle to the inner ear, where the auditory receptors are located. From the inner ear, neural impulses are transmitted to the brain where the auditory picture of the environment is formed and the sound is recognised.

 In the case of limbless amphibians tunnelling in wet and warm soil of the tropics have "seismic" hearing and perceive vibration of the ground by the lower jaw. The sound is transmitted to the inner ear by the skull bones.