decrease the risk of predation. Beaver canals can be over 0.5 km in length. Beavers build canals by pushing through soil and vegetation using their forelimbs. It has been hypothesized that beavers' canals are not only transportation routes to extend foraging, but also an extension of their "central place" around the lodge and/or food cache. A 2012 study of beavers' mark on the landscape found that cut stumps were negatively related to distance from beaver canals, but not to the central body of water. This finding suggested that beavers may consider the canals to be part of their "central place" as far as foraging activity is concerned. Social behavior Communication is highly developed in beaver, including scent marking, vocalization, and tail slapping. Beaver deposit castoreum on piles of debris and mud called scent mounds, which are usually placed on or near lodges, dams, and trails less than a meter from water. Over 100 of such mounds can be constructed within one territory. Beaver colonies with close neighbors constructed more "scent mounds" than did isolated colonies, and the number of scent mounds at each active lodge is correlated with the distance to the nearest occupied lodge. Although seven vocal sounds have been described for beaver, most zoologists recognize only three: a whine, hiss, and growl. Vocalizations and tail slapping may be used to beg for food, signal to family members to warn of predators, or to drive away or elicit a response from predators. Beavers usually mate for life, forming familial colonies. Beaver "kits" are born precocious and with a developed coat. The young beaver "kits" typically remain with their parents up to two years. Kits express some adult behaviors, but require a long period in the family to develop their dam construction skills, and other abilities required for independent life. Diet Beavers are herbivorous generalists with sophisticated foraging preferences. Beavers consume a mix of herbaceous and woody plants, which varies considerably in both composition and species diversity by region and season. They prefer aspen and other poplars, but also take birch, maple, willow, alder, black cherry, red oak, beech, ash, hornbeam, and occasionally pine and spruce. They also eat cattails, water lilies, and other aquatic vegetation, especially in the early spring. Contrary to widespread belief, they do not eat fish. Beavers select food based on taste, coarse physical shape, and odor. Beavers feed on wood, bark, cambium, branches, twigs, roots,