Beaver reproduction and social behavior
In north America the female adult beaver will come into estrus from November to March. This is dependent on north-south latitudes with beavers in colder climates breeding January to March and the warmer southern beavers November to December. With a one time 10 to 12 hour estrus period the beaver may come into estrus again two weeks later if the female beaver is not fertilized. The female is sexually active after 1 1/2 to 2 1/2 years old. The norther latitudes breeding is later and happens into the third winter season. Beavers in south latitudes may breed before 1 1/2 years. Newborn kits are born between February to June and weigh 1/2 to 1 1/2 pounds (230 to 680 g) each and about 5 inches (12 cm) long. They are covered in fur and have a small slightly curved tail. Their eyes are partially open and within an hour the kits begin nurse feeding. The average size litter is 3 to 4 young and its possible for beavers to have as many as 9 kits.
By the time kits are yearlings 70 to 80 percent die from disease or predators. The mother beaver will produce milk for 2 to 3 months. The yearlings will be eating solid food from 1 month onwards. Kits would have started nibbling leafy branches brought in to the lodge by the male beaver, then they start to forage for themselves, always watching and mimicking their elders. The kits learn to swim within 24 hours even though they stay in the lodge until two months old they will of swam in the escape hole water. Yearling beaver are about half their adult weight 20 - 25 pounds.
The parents will have spent much valved time rearing their offspring most likely this is because to survive beavers need to learn many life skills. For this to happen the beaver has very high social behavior skills that evolved over time, this knits the family closer using various ways of communication. Most common is the whine. Kits use whining to get attention for feeding mostly and other social times like grooming and playing. Tail slapping by the beaver is an alarm warning to other members in the area that predators or some kind of danger is close by. Tail slapping is followed with a warning dive completed in one movement then coming back to the surface to view the danger. This action is brought on by a careful use of other senses. The smell and keen hearing weigh up a situation to a point the beaver discomfort level sends out a message of tail slapping that can be heard above and below the water.
The use of scent mounds leaves messages for any beaver that may enter the territory. By leaving an odor the beavers use these aromas for communicating who and what is within the area, including discriminating between the sexes. Beavers share in helping each other to carry out work on lodges, dams and food caching. They show an excellent capacity in getting along living so close to each other in a confined space. Through winter they avoid serious fights, making the young the center of attention. Beavers have evolved a high order of social behavior. If there is a dispute beavers stand up in front of each other in shallow water and start a shoving or wrestling match using the forepaws they push and go should to shoulder until the winner holds his ground and the loser is pushed into deeper water. After the dispute beavers show no sign of submissiveness seen in wolf packs and other mammals.