Young crested porcupines are born with open eyes, incisors, and soft spines that harden a week later.
At birth or shortly afterward, the young crested porcupine’s eyes are open and incisors are completely broken through. The body is covered with short hair, and the back spines are still soft with individual sensing bristles projecting far beyond the spines. Newborns weigh about 1,000 grams or 2.2 pounds, only 3-5% of the mother’s body weight, yet they leave the den for the first time after only one week, at which time the spines begin to harden.
Young crested porcupines begin to feed on solid food between two and three weeks, and the five white stripes found on their side start to disappear at four weeks.
Crested porcupine individuals usually reach adult weight at one to two years and are usually sexually mature just before then.