Reproduction Beaver usually live in family units consisting of the older mated pairs, young from the previous year, and young from the current season called kits. Breeding season takes place in late January or February in most states. Young from the previous year are about 22 months of age at this time and they are evicted from the colony to relocate and seek mates of their own. The gestation period of beaver is 107 days and the adult male and kits usually take up a temporary residence in a bank den while the new litter is being born in April, May or June. The birthing process may take several days, and 3 to 5 kits are a typical litter size.
Beaver kits are fully furred when born, their eyes are open, and the incisor teeth are visible.
Newborn beaver kits take to the water easily, and they might be swimming before they are one day old. Most adult beaver are monogamous, and stay with their mate throughout life. Habits Beaver require deep water for protection from their enemies, and they alter the landscape a great deal with dam building and flooding. Dams can be hundreds of feet in length, and vary in height from only a few feet to 7 or 8 feet, and even higher at times. Permanent lodges are often constructed by piling layer after layer of sticks into a large conical form above the waterline.