The two teeth continuously grow through out the course of the porcupines life. They are not anti-social, however. Porcupines do interact with other animals. During cold winter months, porcupines exist entirely on twigs and bark. A traditional courtship ritual involves the male squeaking out a mating call.
Females respond with a call of their own.
Nose rubbing begins as the female and the male approach each other. One to two baby porcupines are born in each litter after a 7-month gestation period. The young have soft quills, fine hair, and closed eyes. Eyes open within the first 10 days of life, and as the young's quills harden, they begin to forage for food. Those in captivity have a life expectancy of 9-11 years.