Question

Which one of the following animals can hear infrasound?
A. rhinoceros
B. bat
C. dog
D. honeybee

Answer 1

Hint: Infrasound is also called infrasonic sound. Infrasonic sound waves are those sound waves that have frequencies less than 5 Hz. A human ear cannot hear this sound. Very few animals are known to hear and produce infrasonic sound.

Complete step by step answer:
Let us first understand what is infrasound. Infrasound is also called infrasonic sound waves.
When talking about different sounds waves, we classify them according to their frequencies. Now what is frequency? Sound waves are formed by the continuous compression and rarefaction of air. When one complete compression and one rarefaction is completed, it is called one cycle. Frequency is the number of cycles that take place in one unit of time. The unit of frequency is or hertz (Hz).
If 5 complete compressions and 5 rarefactions take place in one unit of time then the frequency of the sound wave is 5 Hz.
Infrasonic sound waves are those waves of sound that have a frequency less than 20 Hz.
Now why are these sound waves classified as infrasonic sound waves? It is because a human ear can hear a sound wave of frequency lying between 20 Hz and 20000 Hz. Therefore, if the sound waves entering our ears have frequency less than 5 hz, then we will not be able to hear the sound. Hence, we call the sound with frequency less than 5 Hz as infrasound.
However, it is found that some animals have the ability to hear infrasonic sounds. Some of the animals that are known to hear infrasonic sounds are elephants, rhinoceros and hippopotamus.

Hence, the correct option is A.

Additional Information
These animals communicate by producing infrasonic sounds. The advantage of infrasonic sound waves is that they travel longer distances. This is because low frequency waves have long wavelengths and hence, there is less scattering of the waves by trees and hills.
Disasters like earthquakes produce infrasonic sounds. Hence, these animals can hear the earth’s vibrations and can save their lives before the disaster.

Note:
Out of the given options, dogs and bats hear ultrasonic sound waves. Ultrasonic sound waves are those sound waves that have frequencies higher than 20000 Hz. Since these waves have very high frequency, they travel short distances.