Illinois is home to two fox species, the red fox and the gray fox, and you would think telling the difference between the two would be pretty simple just based on their common names. 

That's a safe assumption a lot of the time, but some confusion can arise on the rare occasions when red foxes don't have their trademark rusty red color. While most red foxes are, in fact red, several other color variations are possible. They can sometimes be a silvery gray color, black or a cross between red and silver, a color morph known as cross fox, according to the National Park Service. 

But no matter what color a red fox is, there is one easy to way to know if a fox is a red fox. Simply look at its tail. A red fox will have white fur at the end of its tail, no matter what color the rest of their fur is, according to the National Wildlife Federation. Gray foxes will never have a white tip on their tail. Instead, the tips of their tails are always black. 

Gray foxes typically have gray backs, sides and heads, and their legs, belly and chest are a reddish-brown color. Red foxes have white fur on their chest and belly, and their lower legs are typically blackish.

While the color of the tip of their tail is the easiest way to definitely distinguish between these two fox species, there are other differences as well. For starters, gray foxes are slightly smaller than red foxes, with red foxes generally weighing between 10 pounds and 30 pounds and gray foxes weighing between 5 pounds and 20 pounds, according to Animal Diversity Web. Red foxes also have longer legs, a leaner body and bigger feet than gray foxes. Finally, the shape of their eyes can be a distinguishing factor. Red foxes' eyes are more slit shaped, while gray foxes' are more rounded.

Both the red fox and the gray fox live across Illinois, but red foxes are more common in northern Illinois while gray foxes are most common in the southern part of the state and along the Mississippi and Illinois rivers, according to Wildlife Illinois. Red foxes can thrive in a wide variety of habitats, including urban ad suburban ares, forested areas, grasslands and agricultural lands. Gray foxes, on the other hand, generally prefer to live in and near deciduous forests. 

The preferred forest habitat for gray foxes allows them to have one skill that red foxes don't have. Gray foxes are good at climbing trees, Wildlife Illinois reports. They can climb trees both to hunt and escape danger, and they even sometimes rest or sleep in trees. 

Both red foxes and gray foxes are omnivores, and both eat a lot of rodents, Animal Diversity Web reports. They also eat birds, insects and invertebrates as well as fruit. In Illinois, both foxes have few predators. Their main predator is the coyote, although bobcats and even eagles and great horned owls have been known to hunt foxes. 

Although red foxes and gray foxes share many traits and behaviors, they are not that closely related and are only distant cousins, the National Wildlife Federation reports. While both belong to the Canidae family, the red fox and gray fox do not belong to the same genus. This can be differentiated in their scientific names. The scientific name of the red fox is Vulpes vulpes, and it belongs to the Vulpes genus, while the scientific name of the gray fox is Urocyon cinereoargenteus, placing it in the Urocyon genus. 

While red foxes and gray foxes are the most well-known and wide-ranging fox species in North America, there are a few other foxes, including the Arctic fox, kit fox, swift fox and island gray fox. Arctic foxes live in the tundra in the far northern reaches of North America, while kit foxes, the smallest North American fox species, can be found in the southwestern United States as well as northern and central Mexico. Swift foxes live in the grasslands of the northern Great Plains, while island gray foxes live only on some of the Channel Islands off the coast of California.