It is an able swimmer. When disturbed it will stamp its forefeet, growl and gnash its teeth. The quills on the tail may be shaken to produce a rattling sound. Hollow, cone shaped rattle cupules near the end of the tail amplify the sound. The porcupine then turns his back and rushes backward to impale the intruder.
Newborns have a longitudinal band of black hair along the back.
A pattern of 5 longitudinal stripes along the sides will disappear in approximately 4 weeks. The soft quills, which harden in a few days, may be white near the shoulders. The young are born with eyes open and the incisor teeth through the gums. There may be 2 litters per year. Lifespan 10-15 years.