In fall, they prefer woody items. Their winter food is stored underwater near the lodge. Beavers live in families that include an adult pair and one to three years worth of offspring. The kits are born in late spring and can swim within a few hours. Due to their small size and dense fur, they are too buoyant to submerge and are unable to swim out of the underwater entrance to the lodge.
Beavers actively scent mark with castoreum and secretions from their anal glands.
This produces an odor that is musty and pungent. The dam is built across a stream using mud, stones and sticks. They keep adding to the structure, which may reach over 330 feet long and 10 feet high. The entire family helps to build the dam, but the adult female is the most active participant. A canal is also built which aids the beaver in remaining in the water while moving between ponds or going to feeding areas.