Eye color. Much is made of it, but a majority of fanciers have no idea why their breed’s eye color is defined in the breed standard. Other than the cosmetics being the dark eye is considered by most as attractive, many breeders just “do as they are told.”

The majority of breed standards demand dark eyes. In truth, for the greater number of our working, hunting breeds, this dark eye color is at odds with nature. There is no greater cultivator, progenitor than Mother Nature. Repeatedly throughout her creations, we find wild animals with light color eyes, predator, and prey alike. Why then do we humans selectively breed and require dark eyes for the better part of our dogs? For basic aesthetic purposes as humans selected for the more pleasant dark eye than the ‘bird of prey’ color, this being amber to yellow. Such light iris color most likely was unattractive but unsettling to our breed forebears, as it was reminiscent of a predator instead of a companion.

Some claim that dark irises permit our dogs to function more efficiently than light, yellow or amber. This is incompatible with Mother Nature. Consider the Lion, an unrivaled predator whose environment is Sub-Saharan Africa, with its savannas and grasslands. This predator’s eye color is golden or amber whose vision is comparable to a human during the daylight hours but has exceptional night-vision. Both the Cheetah and the Tiger irises are golden or yellow with the Cheetah having poor night vision and the Tiger’s approximately six times better than humans. Note that the development level of night-vision depends on the number of the photoreceptor (rod cells) the animal has and has nothing to do with the color of the iris. Further, wildlife biologists state that fur markings under these predators’ eyes aid their hunting vision, indicating whether they are nocturnal, crepuscular or daylight hunters. What of the Wolf, the only ancestor of the canine species whose eye color is typically gold, some amber or light brown and is often seen in hues of yellow, even gray? Even the Eagle, a bird of prey has a pale yellow iris. All these examples have not been disadvantaged with light eyes while performing their function in order to survive.

Selective breeding and aesthetics have had a great influence on the modern breeds. The long-standing preference for dark eyes may already have had lasting repercussions. Such breeding may cause severe selective pressure -- selecting for dark eyes may carry a recessive mutant gene from the trait, along with a dominant normal gene that masked its effects. Such heterozygous dogs would be hidden carriers, unaffected by the mutation themselves but capable of passing it on to later generations. This should be especially concerning amongst breeds with limited genetic diversity.

Insofar as eye setting, frequently referred to as eye shape, incorrect settings can have injurious implications for many breeds. For example, the ideal Rhodesian Ridgeback eye is round, however never protruding as this can be damaging to the hound in his place of origin. The African Bush consists of Buffalo Thorn, Sickle Bush, and other sharp, thorny fauna which could injure and blind a dog whose eyes are bulging. The English Setter eye set specifies that the eye is neither deep set or protruding with the lids tightly fitted so as not to expose the haw. The Golden Retriever eye shape is to be medium-large with close-fitting rims as well and imparts a kind and pleasant demeanor. On the latter, slanting, narrow, triangular, squinty eyes detract from, moreover modify this expression causing the dog to appear mean. As in the Ridgeback, a prominent eye in both English Setters and Golden Retrievers can easily be injured by the brush and picker bush terrain in which these dogs hunt. Particularly at risk are exposed haws that catch debris causing eye infections or more serious, long-term damage.

Eye setting or shape is necessary for the majority of our working dogs. Regarding iris color, Mother Nature knows best, and we should recognize that tinkering with her work has consequences. We must face facts; the eyes have it.

This article was first published on the Canine Chronicle website.Short URL: http://caninechronicle.com/?p=36254