Sharing the same natural environment with many animal species we tend to automatically assume that they perceive this environment in the same way we do, see the same landscapes and objects and hear the same familiar sounds we associate with mundane places. However, such a belief proves to be erroneous because though almost all animals have organs that can be identified as eyes, ears, noses, etc., they also function differently from similar human organs. Comparing the sense of hearing in birds and humans demonstrates that although there are some similarities in the way they function there are also multiple significant differences that emerged out of different environments, needs, and ways of living bird and human hearing have evolved from. This paper will analyze the hearing sense in pigeons and humans, reviewing the specifics in biological mechanics behind hearing, sensitivity thresholds, as well as functions hearing serves in lives of pigeons and humans.
Both pigeons and humans have ears and possess the ability to hear and differentiate between different sounds. Yet, the structure of human and pigeon ears is quite different which results in substantial differences in the way hearing functions. Unlike humans, pigeons do not have a visible outer ear located in the top part of the head and used to accumulate sound from the environment and transfer it to the inner ear. Instead of outer ears, pigeons rely on small holes located under the feathers on their head to identify the sound. In the case of birds’ avian hearing, the sound travels directly down the auditory canal to the eardrum when the vibrations from the outer environment are transformed into sound. A similar process takes place in the human ear as well. Both in humans and in pigeons, from the eardrum, the sound travels to the inner ear with the help of ossicles bones that serve to transfer the sound. Human ears have 3 ossicle bones while pigeons rely only on one of them for performing this function (Beason, 2004). Once the sound reaches the inner ear, it gets encoded into a nervous system signal which is then interpreted by the brain. The inner ear in birds in filled with fluid and apart from encoding the auditory information serves the function of maintaining equilibrium. In pigeons, the sound reaches the brain as encoded information about the frequency which can be interpreted by the brain similar process takes place in the human ear, though the structure of human ear is somewhat more complex with more canals and other elements (Carpenter, & Huffman, 2013).
The differences in biological structure, living environments, and functionality needs account for significant differences in sensitivity of pigeon and human ears. Human ears hear and recognize sounds in a wide range from 20Hz to 20 kHz sound wavelength with a wide range of sound intensity (volume). Yet, the human ear is most sensitive to sounds between 2 and 5 kHz and operates best with sounds within these limits. This range of sound frequency allows people to identify human voices and numerous other sounds that are essential for effective orientation and survival. The frequency ranges recognize by pigeons and humans have a slight overlap with pigeons recognizing sound frequencies ranging from as low as sounds below 20Hz (infrasound) and up to 10kHz. They are most sensitive to the sounds between 2 and 10kHz, meaning that human ear is better adapted to recognizing higher frequency sounds while pigeons cannot do this because their ears are located very closely together (Beason, 2004). At the same time, pigeons are known to recognize very low-frequency sounds that are inaccessible to humans. In terms of loudness, pigeons prove to have less sensitive ears and are likely not to hear mild sounds that the recognizable by humans. Yet, both humans and pigeons may experience ear damage resulting out of exposure to very loud sounds. One major difference, however, is that pigeons are capable of recovering the sensitivity of their ears while humans are not (Beason, 2004).
The fact that pigeons are capable of recognizing very low frequencies of sound unavailable to humans constitutes a major difference in the way pigeons and humans hear. This capability allows pigeons to be highly effective in navigation and in planning their activities. Namely, research shows that they use infrasound waves emitted by major natural objects like seas and mountains to home on when flying. They also use seismic waves to navigate their routes. Further, they can recognize low-frequency sounds associated with various weather-related phenomena like thunderstorms to know when they are about to come and to protect themselves from potential hazards associated with them (Yodlowski, Kreithen, & Keeton, 2012).
Assessing the key functions fulfilled by hearing in pigeons, orientation, maintaining safety, and communication with other pigeons come to the front. Most importantly, hearing is used for orienting their movements and navigating pigeons’ routes when flying. Sensitivity to low frequency serves them well in navigating the way. Secondly, hearing allows pigeons to protect themselves from numerous hazards in their living environment as hearing the predator getting closer or the approaching car is important for saving their lives. Lastly, they use hearing to communicate messages to other pigeons. For instance, male pigeons may use voice and singing to attract mates.
The function hearing serves in humans are somewhat different. Assisting people in communication with other is perhaps the primary function served by hearing as the way human life is structured makes it inevitably social. Humans also use hearing for protection and ensuring personal safety as loud unexpected noises one hears often indicate the proximity of potential hazards. Lastly, people do use hearing for orientation but not to the same extent as pigeons do as it merely complements other senses for making sense of the space one is in whereas for pigeons hearing appears to be the main orientation tool.
- Beason, R.C. (2004). What Can Birds Hear? USDA National Wildlife Research Center – Staff Publications, 78, 92-96.
- Carpenter, S. & Huffman, K. (2013). Visualizing Psychology, Third Edition, Hoboken, NJ: Wiley & Sons, Inc.
- Yodlowski, M.L., Kreithen, M.L., & Keeton, W.T. (2012, November 8). Pigeons Seeing with Sound: the Perception of Infrasound. Retrieved from https://cerebrovortex.com/2012/11/08/pigeons-seeing-with-sound-the-perception-of-infrasound/.