Red fox have a single annual litter. Litter size may vary, with litters in excess of 15 young documented. Most litters average 4 to 5 pups, also known as kits.
Pups weigh about three or four ounces at birth. They are born blind and helpless, but mature quickly. By the time they are 9 days old, their eyes are completely open. Weaning begins when the pups are 4 to 5 weeks old.
Pups will stay within the den for the first month of their lives. Red fox may move their pups once or more throughout the early months of life, particularly if the existing den is disturbed. Once the pups reach 4 to 5 weeks of age, they will start emerging from the den, often playing near the den entrance.
When the pups are approximately 8 to 12 weeks old, they begin to accompany the adults on hunting forays. By time the pups are 16-20 weeks old, they start fending for themselves. Typically pups will remain relatively close to the den for the first several weeks of independence, with most juveniles dispersing in the fall.