Crested porcupines have hollow quills on their tail that sound kind of like a hiss. If an animal any size gets quills in it and doesn't get help soon it has a high chance of dying. Once quills have been used they will be replaced and they will grow to full length in 4 to 6 months. The quills' barb tipped ends have little scales. Once the quill is in the animal, it spreads out making it even harder to remove.
Porcupines have poor vision, good ears and nose.
Fishers are weasels and they are about the same size as a big house cat. If forest rangers think porcupines are killing too many trees they will release some fishers in that area. One porcupine was known for using thin branches as elevators. Heights don't come even close to scaring them. Porcupines might not be the fastest rodents but they are agile for their size, weight, and bulk.