Eye color in dogs, like in many other species, is determined by genetics. Most dogs have brown eyes simply because the gene that codes for this color is dominant in many breeds. Specifically, brown eye color is due to the presence of pigments called melanin in the iris, which is the colored part of the eye.

However, there are several eye colors that dogs can have, including blue, green, and even heterochromia, where each eye is a different color. These variations are due to different genetic combinations and may be more common in certain breeds or specific bloodlines.

Human preference

In addition to genetics, human preference can also play a role in selectively breeding dogs with certain eye colors. For example, in some breeds, such as the Siberian Husky, blue eyes are highly prized and may be selected for by breeders, increasing the frequency of this trait in the population of these breeds.

Additionally, human preference can influence the perception of the beauty or attractiveness of certain canine eye colors. People may have different tastes and aesthetic preferences, which can influence which characteristics are considered most desirable in a dog, including eye color.

Between evolution and breed standards

Dog eye color can be influenced by both natural evolution and artificial selection by humans to meet desired breed standards.

1. **Natural Evolution**: Over the course of evolution, dog characteristics, including eye color, may have been shaped by natural selective pressures. For example, eye color may have provided adaptive advantages in different environments, such as camouflage or protection from bright sunlight.

2. **Artificial Selection**: For thousands of years, humans have bred dogs to serve specific purposes, such as work, companionship, or competition. During this selective breeding process, humans may have favored certain traits, including eye color, according to established breed standards. This can lead to the prevalence of certain eye colors in certain breeds, due to both human preference and breeder selection criteria.

Therefore, dog eye color is the result of a complex interaction between natural evolution and human influence through selective breeding.