Innovative studies have revealed the evolutionary path of cat eye colors, illuminating an unexpected origin responsible for their impressive diversity.
In a revolutionary study, researchers thoroughly recorded the eye shades of modern cats and used advanced computer simulations to map the evolutionary path of these colors throughout the cat lineage. Their analysis led to a surprising discovery: the ancestor of all cats likely had gray and brown eyes, with gray acting as a stepping stone for the development of other pigments.
Interestingly, the closest relatives of today’s cats, including Prionodon, hyenas, and genets, mainly have brown eyes, suggesting a common ancestry marked by this specific eye color. However, a significant change happened with the emergence of the Felidae family millions of years ago, resulting in the wide range of eye colors seen in cats today.
The evolution of cat eye colors presents an intriguing narrative. “Suddenly, you witness a burst of eye color diversity. You see blue, green, and yellow, among others,” commented the main researcher, Julius Tabin, a PhD student at Harvard University (USA).
Tabin and his associate carefully cataloged the eye pigmentation of over 40 cat species, using online images for their analysis. They then combined this data with existing knowledge of the evolutionary ties among living and extinct cats, using statistical models to predict the eye color of early felines, as reported by LiveScience.
Excluding selectively bred house cats, current observations identify five main eye colors within the Felidae family: brown, gray, yellow, green, and blue. Interestingly, some species like Amur leopards, rusty-spotted cats, South African wildcats, and lynx exhibit a wide range of eye colors, highlighting the complexity of feline eye genetics.
The coloration of cat eyes is controlled by the interaction of two primary pigments, eumelanin and pheomelanin. Brown eyes have high levels of eumelanin, while yellow eyes have high concentrations of pheomelanin. Gray eyes, however, have moderate amounts of both pigments, allowing them to transition between different shades. Blue and green eyes, on the other hand, have reduced levels of both pigments.
While the emergence of gray eyes can be traced back to a lucky mutation in the common ancestor of all cats, the origins of other eye colors are still unknown. Despite thorough research, scientists have not yet found clear links between eye color and external factors such as physical characteristics, behaviors, or environment. Some theorize that mate choice could be a key factor in the variety of eye colors, mirroring similar processes seen in human populations.
As the study awaits peer review, experts outside the research team have suggested alternative theories. Evolutionary geneticist Shu-Jin Luo proposes that eye color might be a “byproduct” of selective pressures favoring fur color, while evolutionary biologist Rosalyn Price-Waldman suggests that eye colors might evolve randomly, as long as they do not disadvantage the cats.
The results of this revolutionary study provide unparalleled understanding into the evolution of cat eye colors, illuminating the complex processes that have formed these enchanting features.
Image credit: Shutterstock
