Foxes turning black is a rare but interesting phenomenon in nature. This article will examine the reasons why some foxes undergo this color change. We’ll look at the genetics, biology, and evolutionary advantages behind this trait. Read on to learn the answers to common questions about black foxes.
What Causes a Red Fox to Turn Black?
The red fox (Vulpes vulpes) is the most common and widespread fox species. They have the iconic red-orange fur that people associate with foxes. However, a genetic mutation can cause a red fox to turn black.
This is called melanism. It’s a mutation in the melanocortin 1 receptor (MC1R) gene. The MC1R gene provides instructions for making the protein that controls pigment production. When the gene mutates, it causes the fox to produce more dark pigment, or melanin. This overwhelms the red pigment, causing the fur to turn black.
The mutation is simple dominant. That means a fox only needs one copy of the mutated gene to exhibit black fur. If two black foxes mate, all of their offspring will also be black. About 10% of red foxes carry the gene for melanism. But it’s only expressed in about 1% of the population since both parents need to carry it.
Where Are Black Foxes Found in the Wild?
Black foxes are most common in North America. The highest densities are found in the Appalachian and Ozark mountains. They are also present in small numbers across Canada, Alaska, and the upper Midwest.
In Eurasia, black foxes appear in pockets of Eastern Europe and Russia. Melanism is rarer outside of North America, occurring in an estimated 1 out of every 125,000 red foxes. It seems the genetic mutation first arose in North American foxes. From there, a small number spread to other areas via migration events.
| Location | Black Fox Population Density |
|---|---|
| Appalachian Mountains | 1 in 10 |
| Ozark Mountains | 1 in 10 |
| Eastern Canada | 1 in 100 |
| Alaska | 1 in 100 |
| Upper Midwest U.S. | 1 in 1,000 |
| Eurasia | 1 in 125,000 |
Are Black Foxes a Separate Species?
No, black foxes are not a distinct species from the red fox. They can freely interbreed and produce viable offspring. The only difference is their fur color due to the genetic mutation.
Some people call black foxes the “Silver Fox.” But this is simply a nickname referring to their dark charcoal coats. There are no structural or biological differences between black foxes and red foxes.
At one time, scientists believed black foxes in North America might be a separate species called “Vulpes fulva.” But this was disproven. DNA analysis confirms black foxes are genetically Vulpes vulpes. Their coats are just expressing melanism.
Are Black Foxes Bigger Than Red Foxes?
Sometimes black foxes can appear larger than their red counterparts. But in reality, there is no difference in size between red and black foxes.
The idea that black foxes are larger likely comes from their winter coats. Black foxes are sometimes spotted in winter when their fur is longer and fluffier. The fuller, darker coat against the snow can make them appear bigger. But when you compare a black and red fox of the same age and season, their body size is the same.
Adult red foxes weigh 8 to 15 pounds and stand 15 to 17 inches tall. This is the same for melanistic black foxes. There are no studies that have found bigger body or bone structure in black fox populations. So while winter coats can look larger, red and black fox sizes do not differ.
Do Black Foxes Have Superior Night Vision?
A common myth suggests that black foxes have better night vision than their red counterparts. However, no scientific evidence supports this belief.
In reality, the night vision abilities of black and red foxes are identical. Like most canids, foxes have excellent night vision due to a reflective retina and large pupils that let in more light. While their vision is adapted for dim light, black foxes do not see any better at night than red ones.
The myth may arise from the fact that black fur provides better camouflage at night. Dark pigment could theoretically help black foxes hide from prey in low light. But the visual acuity itself does not differ between color morphs. Both black and red foxes see equally well after dusk.
Are Black Foxes Better Camouflaged for Winter?
It’s true that a black winter coat can provide better camouflage for foxes in certain snowy regions. This helps explain why the black fox mutation has persisted in northern climates.
Snow reflects UV light. Red foxes’ coats absorb UV, making them stand out against the white background. But black fur absorbs less UV and blends into the snow. This can provide an adaptive advantage during winter months in northern areas.
That said, red foxes are still quite successful in snowy areas. Their populations thrive across Canada, Alaska, and other northern regions. Black fur only appears to give a slight camouflage edge in certain conditions. Both color morphs use the snow cleverly to hunt prey and avoid predators.
Do Black Foxes Have an Advantage Hunting at Night?
As we discussed earlier, black foxes do not actually have superior night vision compared to their red cousins. But some believe their dark fur helps camouflage them when hunting nocturnal prey such as rodents. However, there is no evidence that melanistic foxes have higher hunting success rates after dusk.
In fact, one study found that red foxes in Canada altered their hunting schedule to target more diurnal prey in winter. This was believed to mitigate any disadvantage their coat color had at night. This shows how adaptable red foxes are even without black fur.
Overall, both black and red foxes are skilled nocturnal predators. While dark pigment could theoretically help camouflage at night, no data shows black foxes get more prey in low light conditions. More research is needed to compare their nighttime hunting success.
How Did the Black Fox Mutation Originate?
The genetic mutation causing melanism likely first appeared in North America over 200 years ago. Scientists traced the origin to a single ancestral fox sometime in the 1700s or 1800s.
The mutation was likely random and spontaneous rather than the result of environmental pressures. Mutations happen often during DNA replication, and by chance this particular one occurred in the fox MC1R gene. It proved advantageous and was selected for, spreading through fox populations.
Once the mutation arose, black foxes remained concentrated in certain areas of North America. Only a handful spread to Europe and Asia. The frequency of black foxes is much lower outside North America. But as migration events continue, black fox genes can disperse to new areas over time.
Are Black Foxes Rare and Endangered?
Black foxes are rarer than their red counterparts, but they are not considered endangered. Their populations appear stable, especially in certain U.S. regions where the melanism gene is well established.
There could be some concern that interbreeding with imported red foxes may reduce black fox numbers in the Eastern U.S. But overall, the black fox remains common enough that it is not a conservation priority.
However, Russia has classified its small black fox population as endangered. Logging and fur trapping in the 20th century greatly reduced their numbers. Outside of North America, black foxes are quite rare. These small populations would be at higher risk if hunting or habitat loss increased.
Do Black Foxes Have Better Fur for Coats?
In the fur trade, black fox pelts are considered more valuable than red fox. The extreme rarity of black foxes increased their desirability for fur clothing.
Some also believe black fox fur is more lustrous and silky. This is influenced by genetics, not just color. Farmed silver foxes bred for fur are descended from the black color mutation but now exhibit a broad range of coat colors.
Wild black foxes still represent a prize for trappers and furriers. But there is no objective evidence their fur differs significantly in quality, softness, or insulation from typical red foxes. Yet the novelty and scarcity of black fur still commands higher prices.
Conclusion
While not a distinct species, the rare black fox is a unique morphe of the red fox. The genetic mutation for melanism provides camouflage advantages in certain environments, leading it to become established in North American and some Eurasian fox populations.
Despite myths around eyesight and hunting, black fox biology itself does not differ from red foxes. But the rarity and beauty of their dark pelts will continue to fascinate both scientists and fur enthusiasts alike. With stable populations, the black fox will likely persist as an elusive and revered creature.