Unveiling the Mystique of the Cat's鸳鸯Eye Phenomenon

The Enigma of the Cat's OddEyed Charm

ODD EYE: The Phenomenon of Heterochromia

The word "odd" in English refers to odd numbers, but in the context of cats or dogs, it describes a unique condition where one of the eyes has a different colored iris. This condition is known as heterochromia. Despite the term "syndrome" included, it is not a disease but rather a description of the eye's color variation, commonly known as "mismatched eyes" or "split eyes" in everyday language.

DoubleEyed Oddity as a Sign of Fortune

    In ancient Japan, cats with one golden eye and one blue eye were called "kinme" and "ginme," and they were considered symbols of good fortune. In Thailand, the original home of the Siamese cat, such cats were referred to as "diamondeyed." Due to their rarity, when people encountered these cats, they were revered as omens of luck and held in high regard.

    Heterochromia, when applied to humans, can be a sign of a medical condition. It may be caused by genetic factors, or it could result from diseases or injuries that damage the iris.

Which Cat Breeds Are Prone to Mismatched Eyes?

    Mismatched eyes are more common in white cats or those with predominantly white fur. Purebred Turkish Van cats, Angora cats, and Japanese Bobtail cats are also more likely to exhibit this trait. Japanese Bobtails, in particular, often have blue eyes or heterochromia, with some even displaying a tricolor pattern with blue eyes. Breeders sometimes selectively breed to increase the likelihood of producing offspring with heterochromia.

Genetic Factors Behind White Fur and Blue Eyes

    Why do blueeyed white cats tend to have hearing impairments? While Siamese and Himalayan cats also have blue eyes, they do not suffer from hearing issues. Hearing impairments are more prevalent in white cats with blue eyes, which is partly due to genetics.

    White cats with white fur can generally be categorized into two types:

    White Gene (W Gene)

    The first type is a dominant gene that can override all other genes responsible for determining a cat's coat color, effectively covering them all. This gene is known as the genetic marker.

    Piebald Gene

    The other type involves cats with white patches, such as calico or tortoiseshell cats, where white fur appears in specific areas due to the piebald gene at play.

    The white gene (W gene) is believed to influence both eye color and hearing. The W gene lacks melanocytes, and the absence of these cells affects the cat's eye color, resulting in blue eyes. Blue eyes are not simply blue because the eyes are blue; they appear blue because of the lack of melanocytes.

Hearing Impairment: A Consequence of Malformed Cochlear Sensors

    Hearing impairments are caused by incomplete development of the sensors in the cochlea. These sensors, like melanocytes, are derived from the same cells. The W gene's influence on melanocytes can affect the development of sensory organs, leading to hearing impairments.

    The formation of fur color, eye color, and hearing is all related to melanocytes. Therefore, the extent to which the W gene affects melanocytes determines whether a cat's eyes will be blue and whether they will suffer from deafness.

    White cats with blue eyes have a 60% to 80% chance of experiencing hearing impairments, while nonblueeyed white cats have a 10% to 20% chance. For heterochromic cats with one blue eye, there is a 30% to 40% chance that the blueeyed side will have hearing impairments. Some white cats with blue eyes may have normal hearing in their youth but experience a decline in hearing by the age of 5 to 6.

    Many researchers believe that the blue eyes and hearing impairments in cats are determined by more complex genetic factors. Thus, the world of cats is filled with mysteries, and it's possible that new genetic factors influencing eye color will be discovered in the future.

    White cats with blue eyes, lacking melanocytes, may find direct sunlight uncomfortable. If you have such a cat at home, be sure to take note. If your cat has hearing impairments, there's no need to worry too much in its familiar environment, but be cautious not to startle it by touching it while it's sleeping. Instead, walk slightly heavier when passing by to let it feel the vibration, helping it get used to you communicating with it in this manner.