I found that I couldn't put these books down and I read them cover to cover in one sitting.  I'll be on the lookout for more books with Porcupine in the title after reading these two.

In To The Porcupine Cave
And Other Odysseys
Adventures of an Occasional Naturalist
by Willian W. Warner
published by National Geographic Society
ISBN 0-7922-7688-4

There's a Porcupine in My Outhouse
Misadventures of a Mountain Man Wannabe
by Michael J. Tougias
published by Capital Books
ISBN 1-931868-62-X