Foxes come in a variety of coat colors and patterns, but most people are familiar with the common red fox with its distinctive rusty red fur. While red is the most common fox eye color, some foxes actually do have blue eyes! In this article, we’ll take a look at what causes blue eyes in foxes and which fox species can have this rare eye color.
What Causes Blue Eyes in Foxes
Eye color in foxes, like in humans and other animals, is determined by genetics. The main gene involved is the melanocortin 1 receptor (MC1R) gene which controls how much of the dark pigment melanin is produced in the iris of the eye. The less melanin, the lighter the eye color.
The most common fox eye color is amber or light brown. This is caused by a moderate amount of melanin. Albino foxes lack melanin entirely, so their eyes appear pink or red. The rarer blue or dark gray fox eye color is caused by a mutation in the MC1R gene that limits melanin production in the iris.
Fox Species with Blue Eyes
While not unheard of, blue eyes are quite uncommon in foxes. Here are a few of the fox species in which they have been observed:
Arctic Fox
The Arctic fox has a lighter colored coat to blend in with snowy Arctic environments. Their thick fur is usually white or grayish-brown in the summer. In the winter, their fur turns completely white except for a black tip at the end of their tail.
While amber/brown eyes are still the most common, Arctic foxes are one of the fox species most likely to have blue eyes. Up to 10% of individuals may have blue eyes due to reduced melanin. The blue eye color allows more light to enter the eye in the dim Arctic environment.
Red Fox
The familiar red fox can sometimes be born with blue eyes as well, though it is less common than in Arctic foxes. The mutation responsible for blue eyes likely arose in red foxes first before being passed on to other fox species through hybridization thousands of years ago.
Today, less than 1% of red foxes have blue eyes. However, the percentage was likely higher when blue eyes first appeared as a new mutation and before spreading to other species diluting the frequency.
Gray Fox
The gray fox of North America gets its name from the salt-and-pepper gray fur covering most of its body. The gray fox is not as adapted for cold climates as the Arctic fox and has more reddish fur on its sides, neck, legs, and underside.
Gray foxes with blue eyes can on very rare occasions be found. Overall, the eye color of the gray fox mirrors that of the red fox with most having light brown or amber eyes.
Kit Fox
The kit fox is a small desert fox found in arid habitats of western North America. Its fur is pale gray or yellowish-gray. This species has the largest ears relative to body size of any canid species.
While primarily having amber/brown eyes, kit foxes will sometimes have pale grayish-blue eyes. Overall, blue eyes appear to be more common in kit foxes than red foxes, but less common than Arctic foxes.
Swift Fox
Closely related to the kit fox is the swift fox of the Great Plains region of North America. It has similar coloring of pale gray or yellowish fur.
Like the kit fox, the swift fox usually has light brown eyes, but occasionally blue eyes will be seen. Overall incidence of blue eyes is low but comparable to the kit fox.
Are Blue Eyes Beneficial for Foxes?
The benefit of blue eyes for foxes isn’t entirely clear. In humans, there is no known beneficial effect of blue eyes except perhaps increased sensitivity to changes in ambient light levels. Similar light sensitivity may help foxes like the Arctic fox in the dim light of the Arctic winter.
However, foxes with blue eyes are sometimes more sensitive to bright light due to decreased melanin. One hypothesis is that the blue eye color mutation originally arose as a side effect of a different beneficial genetic mutation that ended up spreading through fox populations.
Fox Eye Color Frequency
Here is a table summarizing the typical frequency of different eye colors in fox species:
| Species | Amber/Brown | Blue |
|---|---|---|
| Red fox | 99% | Less than 1% |
| Arctic fox | 90% | Up to 10% |
| Gray fox | 99% | Less than 1% |
| Kit fox | 90% | 10% |
| Swift fox | 90% | 10% |
Conclusion
While most foxes have amber or brown eyes, some species like the Arctic fox and kit fox do occasionally have striking blue eyes. This is caused by reduced melanin production, resulting in less pigmentation in the iris.
The blue eye color mutation likely arose first in red foxes before spreading to other species through interbreeding. Blue eyes can potentially provide increased light sensitivity, but may also come with drawbacks like photophobia. Overall, the brilliant blue fox eye color remains a rare but beautiful sight in nature.
