While there are two known species of white squirrels in Asia, there aren’t any in North America, so if you’ve spotted an all-white or mostly white squirrel in the wild here, you’ve seen something quite rare. But to understand why, some background is in order.

Most of the white squirrels seen in North America are genetic color variants of the eastern grey squirrel.

For some of these eastern grey squirrels, their unique coats are caused by albinism, a congenital disorder characterized by little or no production of melanin. This lack of melanin makes the albino animal’s eyes appear pink or red, the color of its blood vessels.

However, squirrels with completely white coats and dark eyes are likely leucistic.

Leucism involves a partial loss of pigmentation and it’s often mistaken for albinism, but while leucistic animals have white, pale or patchy coloration, their eye color is unaffected.

But then there are the white squirrels that aren’t albino or leucistic.

“Still rarer seems to be the type of coat pattern we have here in Brevard, North Carolina. The coat is mostly white but there is a distinctive (gray) head patch and dorsal stripe that broadens in the shoulder region,” writes Robert Glesener, research director of the White Squirrel Research Institute. “There is some evidence that this pattern is inherited.”

An albino eastern grey squirrel in Olney, Illinois. Tony Campbell/Shutterstock

Where Can You See Them?

Eastern grey squirrels are a common species, so you could technically spot a white squirrel anywhere in the animal’s native range.

The squirrels inhabit the eastern and midwestern U.S. and the eastern provinces of Canada, but certain cities and towns are known for their large population of white squirrels, including Brevard, North Carolina; Marionville, Missouri; Olney, Illinois; Kenton, Tennessee; and Exeter, Ontario.

But your odds of seeing a white squirrel are higher in Brevard. Glesener’s research has found that almost one in three of the city’s squirrels has white fur, meaning it has the highest percent white of any known squirrel colony.

In many of the places where white squirrels thrive, their colonies can be traced back to pet white squirrels that were released or escaped into the wild.

In the case of Brevard’s white squirrels, a local resident received a pair of white squirrels — which had escaped from a Florida carnival — as a gift in 1949. Eventually, one of these squirrels made another jailbreak and began breeding in the wild.

A white squirrel peeks out from behind a tree at Brevard College in Brevard, North Carolina. Laura Moss/MNN

Why Do They Flourish in Certain Areas?

Albinism can often be a detriment to an animal’s survival.

"Their rate of survival is virtually zero,” says Chad Staples, a curator at Featherdale Wildlife Park. "Predators easily pick them out of a group. Families and social groups can exclude them because to every other member, they look foreign."

So why do squirrels with white fur thrive in certain areas?

First of all, there’s some evidence that in some circumstances, white coloration could be advantageous because predators may not identify an all-white creature as prey.

Secondly, locations with large populations of white squirrels tend to be cities and towns where predators are limited.

However, the biggest factor that contributes to the squirrels’ survival is that they often receive some degree of protection from residents.

While eastern grey squirrels are often considered pests, white ones can become prized and even celebrated. In many places, the squirrels are a draw for visitors, bringing in steady tourism money.

“We’ve had people come all the way from Indonesia, from Australia. Many people come from London, just to see the squirrels,” Clint Wise, owner of Marionville, Indiana’s White Squirrel Hollow Bed and Breakfast, told Rural Missouri.

In Brevard, white squirrels are so prized that in 1986, the city council passed an ordinance establishing a sanctuary for the animals, and today they’re celebrated at the annual White Squirrel Festival.

When locals value white squirrels over their gray counterparts, they select against the animals’ normal coloration, and after a few generations, genes for white fur become more common, allowing white squirrels to flourish.