Why does a cat appear white? - briefly
A cat appears white due to the specific pigmentation of its fur and the unique structure of its hairs. The combination of these factors reflects light in such a way that our eyes perceive the cat as white.
Why does a cat appear white? - in detail
The appearance of a cat as white is determined by several factors, primarily related to its genetics and the structure of its fur.
Firstly, it is important to understand that true white cats are relatively rare. Most cats perceived as white are actually diluted versions of other colors. This dilution is due to a specific gene known as the "D" or "dilute" gene. When this gene is present in two copies (DD), it causes the cat's fur to appear lighter and more washed out, often giving the impression of whiteness.
However, there are indeed cats that carry a unique genetic trait specifically for white coloration. This trait is associated with the "W" or "white spotting" gene, which has several variations: W (dominant white), w^c (chinchilla white), and w^s (extreme white spotting). When these genes are present in homozygous form (WW, w^cw^c, or w^sw^s), they can result in a cat with a predominantly white coat.
Moreover, the pattern of white fur on a cat's body is influenced by another gene called "S" or "piebald spotting." This gene determines where the white spots appear and how extensive they are. In conjunction with the W gene, the S gene can create various patterns such as bicolor (white with another color) and van (a mostly white cat with a colored patch on the head).
It is also worth noting that albinism, a condition caused by the absence of melanin production, can result in a cat appearing white. However, true albino cats are extremely rare and often have distinctive features such as pink or blue eyes and sensitive skin prone to sunburn.
In summary, a cat's appearance as white is largely governed by its genetic makeup, particularly the presence of dilution genes (D) and white spotting genes (W). The S gene further influences the pattern of white fur, leading to various coat configurations that can give the impression of whiteness. Understanding these genetic factors provides insight into the complex interplay that determines a cat's coloration.