Birth - When pups are born, they weigh approximately one pound. They are blind, deaf, and darkly furred with small ears, rounded heads, and little to no sense of smell. They cannot regulate their own body temperature. Motor skills involve a slow crawl mainly with the front legs only, sucking, and licking. They possess a good sense of balance, taste, and touch. Vocal sounds include whining and yelping. A nursing pup will feed four or five times a day for periods of three to five minutes. On average females will gain 2.6lbs. and males 3.3lbs. per week over the next fourteen weeks. This time is known as the "period of maximal growth."

2 weeks - The eyes first open and are blue at 11-15 days. Vision is poor and pups are not able to perceive forms until weeks later. Milk incisors grow in by 15 days and small pieces of meat regurgitated by adults are able to be eaten. Pups should begin to stand, walk, growl, and chew, as well as make their first high-pitched attempts at howling.

3 weeks - Pups begin to explore outside the den, romping and playing near the entrance. Hearing begins to develop. At 27 days the ears begin to raise and at 31 days the ears are mostly erect. The tips are still floppy. Canines and premolar teeth grow in.

4 weeks - Pups weigh in at 5-6lbs. Adult hair begins to grow in around the nose and eyes. Bodies begin to take on adult conformation though the head and feet are disproportionately large. High-pitched howls are gaining strength in volume. The mother may go off for hours on end to hunt, leaving the pups with a sitter. Dominance and play fighting begin with a pup hierarchy slowly being established.

5 weeks - Gradual process of weaning officially begins. Pups can follow adults up to one mile from the den.

8 weeks - Body conformation further developes, though the head and feet are still disproportionately large.

8-10 weeks - Pups can move freely from the den and a rendezvous site; Weaning is complete, with pups feeding on food provided by adults. Adult hair becomes apparent on the body.

8-16 weeks - Eyes gradually change from blue to the natural eye color.

12 weeks - Pups begin to accompany adults on hunting trips. They do not remain for the entirety of the hunt. After a short while they will return to rendezvous site by themselves.

3.5 months - The "period of rapid growth (14-27 weeks)" begins. Pups will gain approximately 1.3lbs. per week for the next three months.

4-6 months - Milk teeth are replaced.

6 months - Pups begin to accompany adults on longer hunts. A pup’s appearance is now nearly indistinguishable from an adult’s.

7 months - The "period of slow growth (27-51 weeks)" begins. Female pups will gain approximately .07lbs. per week. Male pups will gain approximately .4lbs. per week. Pups begin to travel with pack, spending less time at the dens or rendezvous site.

7-8 months - Pups actively begin hunting.

1 year - End of skeletal growth.

22 months - Sexual maturity.