In cute animal videos, one of the most fascinating traits is of the animals bring able to move their ears. Dogs, cats, monkeys – nearly all animals that humans interact with can move both their ears. Several theories have been stated about why animals do so. Due to the flapped nature of their ears, ventilation in their ears is an issue. Thus, they move their ears. Secondly, a dog or related species such as wolves, get alert in the face of danger by erecting their ears. Other mammals use the trait to pinpoint a location, especially during hunting.
One might wonder that animals so closely related to humans (in a biological sense, all the animals listed above are MAMMALS, including humans) have such an ability, isn’t it odd that humans do not? Well, as it turns out, there is a rare bunch of people who voluntarily move their ears. These individuals, called ‘ear wigglers’ constitute only 10 to 20% of the population.
Do humans need to wiggle their ears?
No, humans do not need to wiggle their ears. Through years of evolution, from being cave-dwellers to living in skyscrapers, from having to hunt for food to being served food on a silver platter, humans have vastly deviated from animalistic instincts.
Mainly, since humans do not encounter situations which would require them to hunt for food, wiggling ears is not a trait of use. Thus, those who can wiggle their ears possess a VESTIGIAL trait. A vestigial trait or part is defined as a remnant of a body part (such as the tailbone) or a trait (such as ear wiggling) which was probably beneficial to our evolutionary ancestor but plays no crucial role in our bodies now.
For apes and monkeys, our evolutionary cousins, ear wiggling is also a way to express facially. The movement of the ears helps them create a variety of facial expressions. One can assume that the ancient human species used this trait for several roles, none of which are required now. Since evolution has minimized EYEBROW RIDGES in humans, we use our eyebrows to make facial expressing, thus making the need for ear wiggling redundant.
How can ears be wiggled?
The movement of any part of the body is a result of MUSCLES. Muscles engage in CONTRACTION and RELAXATION, thereby propelling the movement of the various parts. Following this logic, ear wiggling is also controlled by muscles in the ear. The control over the ears muscles depends on whether someone can move them. But a large population cannot.
There are three EXTRINSIC (external) muscles of the ear that carry out this function. The three AURICULARIS muscles – AURICULARIS SUPERIOR, AURICULARIS POSTERIOR, and AURICULARIS POSTERIOR – control the external CARTILAGEOUS part of the ear called AURICLE. When the auricularis muscles are active, the auricle is moved backward and forward. The appearance of this action is termed wiggling. A small portion of people who have control over these three muscles can voluntarily and evidently wiggle their ears.
Why can only some people wiggle their ears?
Most scientists attribute a genetic disposition behind this trait. However, the inheritance pattern – how it is passed and who is more prone to getting the trait – is unclear. Still, active genes for control over the muscles have conclusively decided to be the determinant.
Various studies have denoted the trait a DOMINANT or RECESSIVE trait, but there are more factors in this too. Some ear wigglers believe they had ‘learned’ the trait. Popular traits that can be learnt is the ability to raise a brow or touch the tongue to a nose. Both these traits clearly have tricks which can be used to perform these. But such a decision on ear wiggling has not been taken yet. A logical explanation can be that people with a genetic predisposition can learn to wiggle their ears.
Whether or not people can learn to move their ears, or whether it is genetic, we have no biological need to do so. Some websites have instructions by which the trait can be adopted, and if it works, it can be a fun thing to do. If not, we are not missing out on anything.
The control over the auricularis muscles was said to be lost millions of years ago. A mutation in the gene (or a set of genes) caused this trait to disappear in the majority of the population. Several mutations occur in the human body, but not all exhibit themselves as clearly as that of ear wiggling. Chances are that the trait will never diminish and will always exist in a portion of the population. If humans ever need to possess hearing of such precision, this minority will flourish. Until then, it can only be perceived as a party trick.