How many pups are born in a pack each year?
A mature female wolf comes into estrus once a year. Thus, a breeding pair produces one litter of pups each spring, but in areas of high prey abundance more than one female in a pack may give birth. An average litter size for gray and red wolves is 4 to 6, but sometimes fewer pups are born and sometimes more. Several or all may die if food is not readily available for the fast-growing youngsters. Additionally, other predators and diseases such as distemper and canine parvovirus may kill young pups.