Only Mammals Have Ears?
Yes, only mammals have this characteristic. When I refer to ears, I mean the whole external structure of our ear, this part is called auricle. Not all of them, but most mammals have it, just look at them when you leave your house!
A vast majority of terrestrial mammals do have these external ears, called auricle or Pinna. Firstly, there are many adaptations that different species have in order to have better hearing. This provides the ability to perceive danger, even when you’re not looking in that direction.
The ability to hear is therefore very important for the survival of individuals and species. For more social species, such as primates and some bird species, sound is used as a means of contact between them. They can warn the flock of danger, socialize and talk to each other. This is just the basic function of the auricle.
But hearing is not the only function of the ears, the auricles can also serve as thermoregulators, as is the case with elephants. In their case, they can flap their ears to cool their entire body, as well as their blood vessels. By flapping their ears, they can release the extra heat that their bodies possess, in order to relieve the heat in the summer months.
In addition to this function in elephants, the ears are also fantastic for balance in humans. The vestibular system with its 3 fluid-filled loops allows our body and head to balance and move in relation to our surroundings.
These are some of the functions of the ears. But the auricle also has its own specific functions, clearly serving to protect the inner part from damage.
Structure Of The Auricle
The orientation and structure of the pinna are believed to aid in recognizing where the sound comes from, if it comes from the front or from the back, as well as other planes by reflecting waves onto the tympanic membrane. This is interpreted by the brain to determine the orientation and recognize better its surroundings, this is called the Pinna Filtering Effect theory.
Furthermore, the structure of the pinna evolved to enhance the sensitivity of sounds of some particular frequency, like the frequency that the human voice produces. So, scientists speculate that this favored the development in human speech.1
It’s worth noting that not all mammal species have auricles. The greatest examples are marine mammals: neither whales nor dolphins have auricles. This is due to the fact that for the marine environment, having external ears is not favorable. For example, having no pinna makes the organism more hydrodynamic, which makes them swim faster and evade predators.
The ossicles in our ear canal make mammals‘ hearing something special, adapted to survive in any environment. It’s worth noting that many non-mammalian animals have excellent hearing abilities, with different adaptations to ours. Evolution brought this characteristic to mammals as they evolved, and as it was a vital characteristic for all mammals, it has remained so to this day, as it contributes to the survival and reproduction of mammals.
Thank you for reading. If you’re curious and want to learn more, go to the “articles” section or click on the sidebar on the right. Every week there are new articles published and new curiosities, stay tuned! Subscribing to our Newsletter will notify you when a new article drops.
Read Next