The thickness of their pelts varies according to the region they live in. Wolves usually live in packs from 5 to 8 members, but can be as small as 2 or 3 or as large as 15 to 20. They are the only ones in the pack who breed, having one litter a year. Babies are born in the spring. Litter size can range from 1 to 14 pups with 4 to 6 being the average size.
Pure wolves breed once a year, in the wintertime, and have their babies in the spring.
Neither the male or the female is fertile in the summertime, and the male testicles become quite small in the summer. Lower percentage wolf hybrids can breed at anytime throughout the year, much like a dog. The month of October starts the breeding season. The female starts releasing estrogen in her urine which the male wolf detects. He, in turn, starts producing testosterone which starts enlarging his testicles.