John McKinnan, age 9, of Winnipeg, Manitoba, Canada, for his question:

When does a porcupine grow his quills?

The baby porcupine is born with his quills already growing in his coat. ¬But his new born quills are soft and pliable, somewhat like pieces of bendable plastic. At first they are no use for spiking his enemies. However, they grow stronger with every day. At the end of about two weeks, the youngster's quills are hard and sharp and stiff enough to jab into the flesh of his enemies. After about a year, when he reaches his full size, the porcupine of the Canadian woods will be armed with about 30,000 prickly quills.

A newly born porcupine is a whopping baby. He may weigh more than a pound and measure more than afoot. He is bigger than a baby black bear. And the youngster is wide awake, even from his first day. At the age of two days he can climb trees. For about ten days he feeds on mother's milk. Then he learns to nibble his own bark and buds and leafy greenery.