Why is it so important for Billy to capture Mister Ringtail?

Billy is trying to teach his coon dogs to hunt, and he needs Mister Ringtail's hyde to do so.

IT SEEMS THAT THE WORRIES AND WANTS OF A YOUNG BOY never cease. Now that I had my pups another obstacle had cropped up. This one looked absolutely impossible. I had to have a coonskin so I could train them. With my three little traps and a bulldogged determination, I set out to trap Mister Ringtail. For three solid weeks I practically lived on the river. I tried every trick I knew. It was no use. I just couldn't catch the wiley old coons.

In desperation I went to my grandfather. He smiled as he listened to my tale of woe. "Well, we'll have to do something about that," he said. "To train those dogs right, you'll need that coon hide, that's for sure. Now you watch the store while I go over to my tool shed. I'll be right back."