No, only the Arctic fox undergoes an annual color change.
its turns grey
Grey, of course.
Not generally. By and large, fox squirrels remain "red," black squirrels remain sable, and gray squirrels remain gray no matter what the season.
The color of a fennec fox is light brown
You can't. The color of a cauldron is gray and it will stay gray.
The gray fox is classified as Urocyon cinereoargenteus.
There you go! 100% Gray Fox! The gray fox is the only species of fox that I know can climb trees. What you are looking at above is a Gray Foxes Summer pelt, until winter arrives it become much more fluffy. Maybe you might contact your local zoo and ask about it, do some research on google, real-life, or ask wildlife directories. I'll maybe update this answer later...
The answer is the Arctic fox. In summer, the Arctic fox's coat is brown or gray, but it turns white in winter to blend in with the snow for camouflage while hunting. This seasonal color change is known as "moulting."
the gray fox is primarily noctrnal
No. All elephants are gray. However, digital elephants can change color.
Adding gray to a color desaturates it, making it appear less vibrant and more muted. The more gray that is added, the closer the color becomes to a neutral gray itself.
You can change the saturation of a color by adjusting the amount of gray that is mixed with the color. A higher percentage of gray will decrease the saturation, while a lower percentage of gray will increase the saturation. You can do this using image editing software or by changing the color values manually.